Urinary Tract Obstruction

Urinary Tract Obstruction

  • Restricted flow of urine at any point in the urinary tract, from the kidneys to the external urethral orifice (the opening through which urine passes during urination)
  • The urinary tract consists of the kidneys, the ureters (the tubes running from the kidneys to the bladder), the urinary bladder (that collects urine and stores it until the pet urinates), and the urethra (the tube from the bladder to the outside, through which urine flows out of the body)

Signalment/Description of Pet

Predominant Sex

  • More common in males than in females

Signs/Observed Changes in the Pet

  • Abnormal frequent passage of urine (known as “pollakiuria”)—common
  • Straining with slow, painful discharge of urine (known as “stranguria”)
  • Reduced velocity or caliber of the urine stream or no urine flow during efforts to empty the bladder (voiding efforts)
  • Obvious blood in the urine (known as “gross hematuria”)
  • Signs of excess levels of urea and other nitrogenous waste products in the blood (known as “uremia” or “azotemia”) that develop when urinary tract obstruction is complete (or nearly complete): sluggishness (lethargy), dull attitude, reduced appetite, and vomiting
  • Excessive urine in the bladder (causing an overly large or tense/turgid bladder) or inappropriate retained urine (urine remains after voiding efforts); distension of the urinary bladder can be felt during physical examination
  • Occasionally, an enlarged kidney or kidneys may be felt during physical examination in an pet with long-term (chronic) partial blockage or obstruction of the ureter(s), especially when the lesion involves only one side; the ureter is the tube running from the kidney to the bladder
  • Signs of severely excessive levels of urea and other nitrogenous waste products in the blood (uremia or azotemia)—dehydration; weakness; low body temperature (known as “hypothermia”); low heart rate (known as “bradycardia”) with moderately increased levels of potassium in the blood (known as “hyperkalemia”); high rate of shallow respirations; stupor or coma; seizures occurring terminally; rapid heart rate (known as “tachycardia”) resulting from irregular heartbeats induced by severely increased levels of potassium in the blood (hyperkalemia)
  • Signs of rupture or perforation of the urinary tract—leakage of urine into the abdomen causes abdominal pain and distension; leakage of urine into tissues around the urethra (the tube from the bladder to the outside, through which urine flows out of the body) causes pain and swelling in the pelvis or in the tissue between the anus and vulva in the female or anus and scrotum in the male, depending on the site of the urethral injury; fever

Causes

Intraluminal Causes

  • Blockage or obstruction involving the inner, open space of the tubular ureters and urethra
  • Solid or semisolid structures including urinary tract stones (uroliths); accumulations of minerals and inflammatory materials in a matrix (known as “urethral plugs”) in cats; blood clots; and sloughed tissue fragments
  • Most common site—the urethra (the tube from the bladder to the outside, through which urine flows out of the body)
  • Urinary tract stones (urolithiasis)
  • Accumulations of minerals and inflammatory materials in a matrix (urethral plugs)—most common cause in male cats

Intramural Causes

  • Blockage or obstruction involving the wall of a hollow organ, such as the bladder
  • Tumors or cancer of the bladder neck (the junction between the bladder and the urethra) or urethra (the tube from the bladder to the outside, through which urine flows out of the body)
  • Nodular inflammatory lesions, characterized by the presence of pus (known as “pyogranulomatous inflammatory lesions”) in the urethra
  • Scar tissue (known as “fibrosis”) at a site of prior injury or inflammation can cause narrowing (stricture or stenosis), which may impede urine flow or may be a site where debris becomes lodged within the lumen (the inner open space of the ureter [the tube from the kidney to the bladder] or urethra [the tube from the bladder to the outside, through which urine flows out of the body])
  • Fluid buildup (known as “edema”), bleeding, or spasm of muscular components can occur at sites of blockage or obstruction involving the inner, open space of the tubular ureters or urethra (intraluminal obstruction), and contribute to persistent or recurrent obstruction to urinary flow after removal of the intraluminal blockage; tissue changes might develop because of injury inflicted by the obstructing material, by the manipulations used to remove the obstructing material, or both
  • Ruptures, lacerations, and punctures—usually caused by traumatic incidents

Miscellaneous Causes

  • Displacement of the urinary bladder into a perineal hernia; a perineal hernia develops when the muscles supporting the rectum weaken and separate, allowing the rectum and/or bladder to slide under the skin and causing swelling in the area of the anus
  • Nervous system disorders

Risk Factors

  • Urinary tract stones (urolithiasis), particularly in males
  • Feline lower urinary tract disease (FLUTD), particularly in males

Treatment

Health Care

  • Complete urinary tract obstruction is a medical emergency that can be life-threatening; treatment usually should be started immediately
  • Partial urinary tract obstruction—not necessarily an emergency, but these pets may be at risk for developing complete obstruction; may cause irreversible urinary tract damage, if not treated promptly
  • Treat as an inpatient until the pet’s ability to urinate adequately has been restored
  • Treatment has three major components: (1) combating the problems associated with excess levels of urea and other nitrogenous waste products in the blood that build up due to the urinary tract obstruction (known as “post-renal uremia”)—problems include dehydration; low body temperature (hypothermia); accumulation of acidic compounds in the body (known as “acidosis”); increased levels of potassium in the blood (hyperkalemia); (2) restoring and maintaining an open pathway for urine outflow; and (3) implementing specific treatment for the underlying cause of urine retention and urinary tract obstruction
  • Give fluid therapy to pets with dehydration or with excessive levels of urea and other nitrogenous waste products in the blood (uremia or azotemia)
  • When substantial generalized (systemic) problems exist, start fluid administration and other supportive measures first, before relieving the blockage or obstruction; careful decompression by tapping the bladder to remove urine (known as “cystocentesis”) will relieve pressure on the bladder and may be performed before anesthesia and catheterization

Surgery

  • Surgery is required sometimes
  • Urinary diversion by tube cystostomy is useful in selected cases; tube cystostomy is surgical placement of a catheter from the bladder and exiting through the abdominal wall to allow urine to be removed from the body, thus bypassing blockage of the urethra

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Procedures for relief of blockage or obstruction often require, or are facilitated by, giving sedatives or anesthetics; generally isoflurane is the anesthetic of choice; however, a variety of other anesthetics or sedatives can give satisfactory results

Follow-Up Care

Patient Monitoring

  • Assess urine production and hydration status frequently, and adjust fluid administration rate accordingly
  • Verify ability to urinate adequately or periodically use urinary catheterization to combat urine retention
  • If catheter insertion requires repeated use of sedatives or anesthetics or is unduly traumatic, indwelling catheterization with closed drainage is appropriate; however, frequent brief urethral catheterization may be a better choice, if the catheter can be inserted easily on a repeated basis
  • When the electrocardiogram (ECG) indicates changes in the heart rhythm that potentially are life-threatening, use continuous monitoring to guide treatment and evaluate response

Possible Complications

  • Death
  • Injury to the urinary tract, while trying to relieve obstruction
  • Low levels of potassium in the blood (hypokalemia) during post-obstruction diuresis (a condition in which the body produces large volumes of urine after a urinary tract blockage has been relieved)
  • Recurrence of obstruction

Expected Course and Prognosis

  • Long-term management and prognosis depend on the cause of the blockage or obstruction

Key Points

  • Urinary tract obstruction is restricted flow of urine at any point in the urinary tract, from the kidneys to the external urethral orifice, the opening through which urine passes during urination
  • Complete urinary tract obstruction is a medical emergency that can be life-threatening; treatment should be started immediately
  • Partial urinary tract obstruction—not necessarily an emergency, but these pets may be at risk for developing complete obstruction; may cause irreversible urinary tract damage, if not treated promptly
  • Long-term management and prognosis depend on the cause of the blockage or obstruction

Kidney Failure

Kidney Failure – Sudden (Acute) Uremia

  • “Uremia” is the medical term for excessive levels of urea and other nitrogenous waste products in the blood (it is also known as “azotemia”)
  • Sudden (acute) uremia is a clinical syndrome characterized by sudden onset of kidney failure; urea and other nitrogenous waste products build up, leading to clinical signs
  • It is potentially reversible, if diagnosed quickly and treated aggressively
  • The kidney filters the blood and removes various waste products from the body as it produces urine; the kidney is involved in maintaining the normal fluid volume of the body; each kidney is composed of thousands of nephrons (the functional units of the kidney, each consisting of the glomerulus [a tuft of blood capillaries—the “blood filter”] and a series of tubes and ducts, through which the filtered fluid flows, as urine is produced)

Signalment/Description of Pet

Mean Age and Range

  • Peak incidence —6–8 years of age
  • Older pets at greater risk

Signs/Observed Changes in the Pet

  • Sudden onset of lack of appetite (known as “anorexia”); listlessness; depression; vomiting (with or without the presence of blood); diarrhea (with or without the presence of blood); bad breath (known as “halitosis”); wobbly, incoordinated or “drunken” appearing gait or movement (known as “ataxia”); seizures; and production of only small amounts of urine (known as “oliguria”)/or no urine (known as “anuria”) or increased volume of urine (known as “polyuria”)
  • Observed poison or drug exposure; recent medical or surgical conditions
  • Normal body condition and hair coat; dehydration (or overhydration due to administration of fluids); ulcers in the mouth; inflammation of the tongue (known as “glossitis”) and death of tissues of the tongue; low body temperature (known as “hypothermia”) or fever; rapid breathing (known as “tachypnea”); slow heart rate (known as “bradycardia”); inability to feel the urinary bladder during physical examination; and enlarged, painful, firm kidneys

Causes

  • Shock; trauma; blood clots (known as “thromboembolism”); heat stroke; excessive narrowing of the blood vessels (known as “vasoconstriction,” such as following the administration of nonsteroidal anti-inflammatory drugs [NSAIDs]); adrenal gland insufficiency; excessive enlargement or dilation of blood vessels (known as “vasodilation,” such as following the administration of angiotensin-converting enzyme [ACE] inhibitors or medications to decrease blood pressure [known as “antihypertensive drugs”]); prolonged anesthesia; heart failure

Compounds/Medications That Are Toxic to the Kidneys

  • Ethylene glycol (found in antifreeze); antibiotics (aminoglycosides); antifungal medications (amphotericin B); chemotherapeutic agents (such as cisplatin and doxorubicin); nonsteroidal anti-inflammatory drugs; radiographic contrast agents; heavy metals (such as lead, mercury, arsenic, thallium); insect or snake venom; calcium; grape or raisin ingestion; and lily ingestion (cats)

Generalized Disease Affecting the Kidneys

  • Infectious disease (such as leptospirosis or Lyme disease); immune-mediated disease (such as inflammation and accompanying dysfunction of glomeruli [plural of glomerulus] of the kidney [known as “glomerulonephritis”] and inflammation of the arteries [known as “arteritis”]); inflammation of the pancreas (known as “pancreatitis”); generalized disease caused by the spread of bacteria in the blood (known as “septicemia” or “blood poisoning”); blood-clotting disorder (known as “disseminated intravascular coagulopathy” or DIC); liver failure; heat stroke; blood transfusion reactions; bacterial inflammation/infection of the lining of the heart (known as “bacterial endocarditis”); bacterial infection/inflammation of the kidney (known as “pyelonephritis”); and cancer (such as lymphoma; “lymphoma” is a type of cancer that develops from lymphoid tissue, including lymphocytes, a type of white blood cell formed in lymphatic tissues throughout the body)
  • Blockage or obstruction of one or both ureters (the tubes running from the kidneys to the bladder) in cats

 

Risk Factors

  • Preexisting long-term (chronic) kidney disease; dehydration; generalized bacterial infection (known as “sepsis”); low blood volume (known as “hypovolemia”); low blood pressure (known as “hypotension”); advanced age; coexistent disease; low levels of sodium in the blood (known as “hyponatremia”); low levels of potassium in the blood (known as “hypokalemia”); low levels of calcium in the blood (known as “hypocalcemia”); and acidosis (a condition in which levels of acid are increased in the blood)
  • Medications (such as the diuretic, furosemide; nonsteroidal anti-inflammatory drugs; angiotensin-converting enzyme [ACE] inhibitors; antibiotics [aminoglycosides]); prolonged anesthesia; acidifying diets; trauma; multiple organ disease; and high environmental temperature

Treatment

Health Care

  • Inpatient management; eliminate inciting causes; discontinue kidney toxic drugs; establish and maintain circulation and blood flow; treat life-threatening fluid imbalances, biochemical abnormalities, and uremic toxicities
  • If a poison is the likely cause of sudden (acute) uremia and kidney failure, follow appropriate treatment for the specific poison (treatment may include inducing vomiting, flushing of the stomach [known as “gastric lavage”], and administering activated charcoal and specific antidotes); early hemodialysis (procedure to remove waste products from the blood) can eliminate poisons
  • Low blood volume (hypovolemia) or dehydration—correct estimated fluid deficits with normal (0.9%) saline or balanced fluids within 2–4 hours; blood losses may be replaced by blood transfusion; once the pet is hydrated, ongoing fluid requirements are provided; avoid overhydration
  • High blood volume (known as “hypervolemia”) or overhydration—stop fluid administration and eliminate excess fluid by treatment with medications to remove excess fluid from the body (known as “diuretics”) or dialysis (procedure to remove waste products from the body)

Diet

  • Restrict intake of food and water by mouth until vomiting subsides
  • Fat and protein stores will be consumed by the body while pet is not eating (anorexia); resting energy requirements must be provided by 3–5 days, using moderately protein-restricted diets or feeding special solutions formulated to control excessive levels of urea and other nitrogenous waste products in the blood (uremia or azotemia) and supply caloric requirements
  • Nutrition may be provided by intravenous feeding (known as “parenteral nutrition”) in vomiting pets
  • Tube feeding may be provided for pets that are not eating (anorexia) and are not vomiting—caloric and protein requirements may be supplied by using kidney diets that have been liquefied in a kitchen-type blender, special liquid diets, or formulated diets

Surgery

  • Surgical incision into the bladder (known as “cystotomy”) to flush (known as “lavage”) and remove inflamed tissue (known as “debridement”) the lining of the bladder mucosa is not recommended
  • Surgical opening of the urethra (known as “perineal urethrostomy”) to minimize recurrent blockage of the urethra (urethral obstruction) should be considered only when the obstructive disease is localized to the area of the urethra within the penis (known as the “penile urethra”) by contrast x-rays (radiographs) of the urethra

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

Inadequate Urine Production

  • Ensure the pet has normal blood volume
  • Administer medications to remove excess fluid from the body (diuretics), such as mannitol or furosemide (alternative or subsequent to mannitol)
  • If diuretic treatments fail to induce increased production of urine within 4–6 hours, consider dialysis (procedure to remove waste products from the body)

Acid-Base Disorders

  • Bicarbonate

Vomiting

  • No food or water (nothing by mouth) until vomiting subsides
  • Reduce stomach-acid production—famotidine or ranitidine or omeprazole
  • Medication to protect the lining of the stomach (known as a “mucosal protectant”)—sucralfate
  • Medications to control nausea and/or vomiting (known as “antiemetics”)—metoclopramide, ondansetron, or dolasetron

Peritoneal Dialysis or Hemodialysis

  • ”Peritoneal dialysis” is a type of dialysis in which fluids are put into the abdomen and the lining of the abdomen (known as the “peritoneum”) acts as a filter to remove waste products from the blood—after a certain amount of time, the fluids and waste products are removed from the abdomen; “hemodialysis” is a procedure to remove waste products from the blood
  • Dialysis can stabilize the pet until kidney function is restored or until corrective surgery is performed; without dialysis, most pets that produce only small amounts of urine (oliguria) die before kidney repair can occur

Follow-Up Care

Patient Monitoring

  • Fluid, electrolyte, and acid–base balances; body weight; blood pressure; urine output; and clinical status—monitor daily

Preventions and Avoidance

  • Anticipate the potential for sudden (acute) kidney injury in aged pets or those with generalized (systemic) disease, generalized bacterial infection (sepsis), trauma, receiving kidney toxic drugs, multiple organ failure, or those undergoing prolonged anesthesia
  • Maintenance of hydration, mild saline volume expansion, and administration of mannitol may be preventive
  • Monitor urine production and increased levels of urea and other nitrogenous waster products (azotemia) in high-risk pets

Possible Complications

  • Seizures; coma; irregular heartbeats (known as “cardiac arrhythmias”); increased blood pressure (hypertension); congestive heart failure; fluid buildup in the lungs (known as “pulmonary edema”); inflammation of the lungs due to the presence of urea and other nitrogenous waste products (known as “uremic pneumonitis”); aspiration pneumonia; bleeding in the gastrointestinal tract; shock due to low blood volume; generalized bacterial infection (sepsis); stopping of the heart and breathing (known as “cardiopulmonary arrest”); and death

Expected Course and Prognosis

  • Prognosis depends on cause, extent of damage, coexistent diseases, and multiple organ involvement
  • Infectious and obstructive causes have a better prognosis for recovery than toxic causes

Key Points

  • Poor prognosis for complete recovery
  • Potential for complications of treatment (such as fluid overload, generalized bacterial infection [sepsis], and multiple organ failure)
  • Prolonged hospitalization and treatment is expensive
  • Alternatives to conventional medical management are available; they include peritoneal dialysis or hemodialysis (procedures to remove waste products from the blood) and kidney transplantation
  • Leptospirosis has zoonotic potential; “zoonoses” are diseases that can be passed from animals to people

Seizures in Cats

Seizures in Cats (Convulsions, Status Epilepticus)

  • “Seizures” are periods of uncontrolled electrical activity in the brain (also known as “convulsions”); “status epilepticus” is repeated or prolonged seizure activity
  • “Epilepsy”—disorder characterized by recurring seizures that originate from the brain
  • “Idiopathic epilepsy”—epilepsy of unknown cause; syndrome that involves only epilepsy, with no demonstrable underlying brain lesion or other nervous system signs; rare in cats
  • “Symptomatic epilepsy”—epileptic seizures are the result of identifiable, structural brain lesions; frequent in cats
  • “Probably symptomatic epilepsy”—symptomatic epilepsy is suspected, but a lesion cannot be demonstrated; frequent in cats
  • Cluster seizures—more than one seizure in 24 hours
  • Status epilepticus—continuous seizure activity, or seizures repeated at brief intervals without complete recovery between seizures; status epilepticus can be localized (known as “focal” status epilepticus) or generalized (known as “generalized status epilepticus”)—generalized status epilepticus is a life-threatening medical emergency

Signalment/Description of Pet

Species

  • Cats

Signs/Observed Changes in the Pet

  • Localized (focal) seizures with/without secondary generalization are the most frequent—movements of facial muscles predominate, such as twitches of eyelids, whiskers and ears; it may be associated with whole body trembling/shaking, leg motions, hair standing up (known as “piloerection”), dilated pupils, frantic running, and colliding with objects
  • Generalized tonic-clonic motor seizures—symmetrical sustained, repetitive (known as “tonic-clonic”) contractions of leg muscles on both sides of the body and movement of the head up toward the back; often associated with salivation, urination, and defecation—by the time of admission to a veterinary hospital, the gross motor activity may have stopped, but twitching of the lids and body/limb jerks still may be present
  • Injury is frequent—biting of tongue, torn nails or claws
  • Mental status, reflexes, and menace response may be abnormal
  • Other signs and physical examination findings vary, based on underlying cause of the seizures and the severity of the seizures

Causes

  • Pattern of seizures (such as age at onset of seizure activity, type and frequency of seizures) is the most important factor in determining possible causes

Extracranial Cause (Disorder Outside of the Head, Leading to Seizure Activity)

  • Metabolic disorder—low blood glucose or sugar (known as “hypoglycemia”), such as from insulin overdose; low calcium levels in the blood (known as “hypocalcemia”) following surgery to remove the thyroid gland (known as “thyroidectomy”); high blood pressure (known as “hypertension”) secondary to kidney transplant; nervous system disorder caused by accumulation of ammonia in the system due to inability of the liver to rid the body of ammonia (known as “hepatic encephalopathy”)
  • Poisons

Intracranial Cause (Disorder Inside of the Head, Leading to Seizure Activity)

  • Anatomic or structural disorder—congenital (present at birth) malformation
  • Metabolic disorder—storage diseases (inherited metabolic diseases in which harmful levels of materials accumulate in the body’s cells and tissues)
  • Tumors or cancer—meningioma, glioma, lymphoma
  • Inflammatory infectious disease—viral diseases (such as feline infectious peritonitis [FIP]), toxoplasmosis, cryptococcosis
  • Trauma
  • Poisons—insecticides (such as organochlorines, pyrethrins and pyrethroids); chemotherapy drug, chlorambucil, used in lymphoma treatment
  • Blood vessel or circulatory disorders—red blood cell (RBC) count above the normal ranges, characterized by the uncontrolled, but orderly production of excessive numbers of mature red blood cells by the bone marrow (known as “polycythemia vera”) leading to sludging of the blood (known as “hyperviscosity”); a disorder characterized by lack of blood flow to part of the brain, caused by migration of Cuterebra larva (known as “feline ischemic encephalopathy secondary to Cuterebra larva”)

Risk Factors

  • Any brain lesion
  • Treatment with chlorambucil, a chemotherapy drug
  • Kidney failure
  • Diabetes mellitus (“sugar diabetes”)

Treatment

Health Care

  • Outpatient—isolated recurrent seizures in an otherwise healthy pet
  • Inpatient—cluster seizures (more than one seizure in 24 hours) and status epilepticus (repeated or prolonged seizure activity)
  • Constant medical supervision
  • An intravenous (IV) catheter will be established to allow for drug and fluid administration
  • Blood should be drawn for rapid measurement of blood gases, glucose, calcium, and levels of antiseizure drugs (also known as “anticonvulsants”), if pet has been on anticonvulsants
  • Carefully cool the body, if the cat has an elevated body temperature (known as “hyperthermia”)

Surgery

  • Surgical opening of the skull (known as a “craniotomy”)—surgical removal of tumor or cancer (meningioma or other accessible mass)

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Seizure type and frequency determine therapeutic approach

Isolated Recurrent Generalized Seizures

  • Medications to control seizures (known as “antiepileptic drugs” or “anticonvulsants”)—phenobarbital, diazepam
  • Levetiracetam—may be given in combination with phenobarbital
  • Initiate medication gradually to avoid overt sedation; follow the directions for medications as directed by your pet’s veterinarian

Convulsive Cluster Seizures (More than One Seizure in 24 Hours) and Status Epilepticus (Repeated or Prolonged Seizure Activity)

  • Treat cluster seizures and generalized status epilepticus early
  • Medications to control seizures (antiepileptic drugs or anticonvulsants)—phenobarbital, diazepam; choice and method of administration of medication based on status of seizure activity at time of presentation to the animal hospital

Persistent Seizures

  • Propofol (an anesthetic drug) administered at doses below those needed to induce anesthesia

Other Medications

  • Dexamethasone—a steroid to improve fluid buildup (known as “edema”) in the brain secondary to status epilepticus (repeated or prolonged seizure activity) and to treat the primary cause, if generalized (systemic) infectious disease is not suspected
  • Gabapentin to help control seizures
  • Zonisamide to help control seizures

Follow-Up Care

Patient Monitoring

  • Bloodwork (complete blood count [CBC], serum biochemistry profile) prior to initiating treatment, 4–6 weeks after starting phenobarbital, and repeat every 6–12 months
  • Bloodwork (creatine kinase [CK]) to evaluate muscle damage and subtle on-going seizure activity
  • Measure phenobarbital serum level 2 weeks after initiation of treatment; dosage may be changed, based on blood test results; re-measure phenobarbital serum levels periodically until therapeutic range is reached
  • Bloodwork (liver enzymes) 3–5 days after starting treatment with diazepam

Possible Complications

  • Side effects of phenobarbital—low platelet count (known as “thrombocytopenia”), low white blood cell count (known as “neutropenia”), itchiness (known as “pruritus”), or swollen feet; “platelets” and “thrombocytes” are names for the normal cell fragments that originate in the bone marrow and travel in the blood as it circulates through the body; platelets act to “plug” tears in the blood vessels and to stop bleeding
  • Diazepam may cause sudden death of liver cells (known as “acute hepatic necrosis”)
  • Cardiovascular and respiratory collapse from over dose during treatment for status epilepticus (repeated or prolonged seizure activity)

Expected Course and Prognosis

  • Depends on the underlying cause and response to treatment
  • Cats with “probably symptomatic epilepsy” have a good long-term prognosis
  • Cats can recover despite episode of severe cluster seizures (more than one seizure in 24 hours) and generalized status epilepticus (repeated or prolonged seizure activity)

Key Points

  • Treat cluster seizures (more than one seizure in 24 hours) and generalized status epilepticus (repeated or prolonged seizure activity) early
  • Antiepileptic (anticonvulsant) treatment in symptomatic epilepsy may not help until the primary cause is addressed
  • Keep a seizure calendar noting date, time, severity, and length of seizures

Mast-cell Tumors

Mast-Cell Tumors in Cats

  • Cancerous (known as “malignant”) round cell tumor; round cell tumors are made up of cells that appear round or oval on microscopic examination; mast-cell tumors are one type of round cell tumor
  • Tumor arising from mast cells
  • “Cutaneous” refers to the skin
  • Mast cells are connective tissue cells that contain very dark granules; the granules contain various chemicals, including histamine; they are involved in immune reactions and inflammation; mast cells can be found in various tissues throughout the body
  • Differentiation is a determination of how much a particular tumor cell looks like a normal cell; the more differentiated, the more like the normal cell
  • Mast-cell tumors of the skin in cats are classified as “compact” (more benign behavior) or “diffuse” (more undifferentiated and aggressive)
  • Mast-cell tumors also may be found in the tissue immediately beneath the skin (that is, the subcutis), spleen, liver, and intestines
  • Mast-cell tumors are the most common tumor found in the spleen of cats
  • Mast-cell tumors can release histamine, leading to the development of hives, reddening of the skin (known as “erythema”), bleeding and bruising, which can be seen around the tumor

Genetics

  • Increased likelihood of developing mast-cell tumors is seen in certain breeds, indicating that a genetic likelihood exists

Signalment/Description of Pet

Species

  • Dogs
  • Cats

Breed Predilections

  • Cats—Siamese

Mean Age and Range

  • Cats—middle-aged, 8–9 years of age for mast-cell tumors affecting the skin (known as “cutaneous mastocytoma”) and older cats for mast-cell tumors found in the intestines or spleen
  • Cats—histiocytic form of mast-cell tumors of the skin (cutaneous mast-cell tumor) occurs in young cats, mean age of 2.4 years

Predominant Sex

  • Cats—male Siamese

Signs/Observed Changes in the Pet

  • Depend on the location and grade of the tumor

Cats

  • Lack of appetite (known as “anorexia”)—most common complaint with mast-cell tumor of the spleen
  • Vomiting and diarrhea—may occur secondary to mast-cell tumors of the spleen or gastrointestinal tract
  • Long-term (chronic) weight loss
  • Sluggishness (lethargy)
  • Mast-cell tumor of the spleen—enlarged spleen (splenomegaly)
  • Intestinal mast-cell tumor—firm, segmental thickenings of the small intestinal wall; spread (metastasis) to the mesenteric lymph nodes, spleen, liver, and (rarely) lungs

Causes

  • Genetic mutation has been identified in up to 30% of mast-cell tumors

Risk Factors

  • Hereditary
  • Certain breeds of dogs and cats are more likely to develop mast-cell tumors (see “Breed Predilections”)

Treatment

Health Care

Cats

  • Surgery—treatment of choice for mast-cell tumors of the skin; only narrow margins around the removed tumor are necessary, as the majority of tumors do not regrow following narrow surgical margin tumor removal
  • Surgical removal of the spleen (known as “splenectomy”)—treatment of choice for mast-cell tumors of the spleen; splenectomy is recommended in cats with large tumor burden in the abdomen, despite spread of the cancer (metastasis)

Activity

  • Limit activity for pets with heavy tumor burden (such as cats with mast-cell tumors of the intestines or spleen)

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

Cats

  • Lomustine
  • Vinblastine

Cats

  • Symptomatic treatment—Benadryl; famotidine or other histamine-blocking (H2) agents; omeprazole and sucralfate should be considered for any dog or cat with gross mast-cell disease

Follow-Up Care

Patient Monitoring

  • Evaluate any new masses microscopically
  • Evaluate regional lymph nodes at regular intervals to detect spread (metastasis)
  • Check complete blood count (CBC) at regular intervals, if the pet is receiving chemotherapy
  • Check liver enzymes on serum biochemistry profile, if the pet is on certain chemotherapy drug protocols (such as lomustine therapy)

Cats

  • Abdominal, including mast-cell tumor involving the intestine or spleen—abdominal ultrasound every 3 months for 1 year

Possible Complications

  • Low white blood cell count (known as “leucopenia”) due to suppression of the bone marrow (known as “myelosuppression”) secondary to chemotherapy
  • Liver toxicity (known as “hepatotoxicity”)

Expected Course and Prognosis

  • complete surgical removal (excision) of low-grade mast-cell tumors in most locations is curative
  • Complete surgical removal (excision) of high-grade mast-cell tumors or those located in areas associated with a poor prognosis (mucocutaneous junctions [areas where skin and moist tissues of the body come together; for example, the lips]), possibly inguinal regions) often require chemotherapy; median survival times averages approximately 11–12 months
  • Incomplete surgical removal (excision) of a low-grade mast-cell tumor may require additional local therapy with another surgery (often cured) or radiation therapy (85% disease-free at 3 years)
  • Incomplete surgical removal (excision) of a high-grade mast-cell tumor requires additional local therapy, in addition to chemotherapy; median survival times range from 6 to 12 months
  • Spread of the cancer to lymph nodes in the area of the tumor (regional metastasis) should be treated with surgical removal (excision) of the affected lymph node(s) at the time of the primary tumor removal; chemotherapy is necessary; median survival times are typically less than 9 months
  • Spread of the cancer to lymph nodes located away from the tumor or other organs (known as “distant metastasis”) often is treated with chemotherapy or ancillary therapies alone with a median survival of 4 months or less

Key Points

  • All new masses should be evaluated by a veterinarian
  • Fine-needle aspiration and microscopic examination should be performed as soon as possible on any new mass
  • Surgical removal (excision) should be done as soon as possible on any new mast-cell tumor

Mammary Gland Tumors

Mammary Gland Tumors in Cats (Breast Tumors)

  • Cancerous (malignant) and benign tumors of the breast (mammary glands) in cats
  • “Mammary” refers to a breast or mammary gland
  • The mammary glands produce milk to feed newborn kittens; they are located in two rows that extend from the chest to the inguinal area; the nipples indicate the location of the mammary glands
  • Most cancerous (malignant) breast tumors in cats are carcinomas; benign breast tumors in cats include adenomas, fibroadenomas, and papillomas
  • Spread to the lungs (known as “pulmonary metastasis”) is seen in up to 70% of cats with breast cancer

Genetics

  • The high number of Siamese with breast tumors suggests a genetic component; however, specific genes have not been identified to date

Signalment/Description of Pet

Species

  • Cats; breast (mammary gland) tumors are the third most common type of tumor seen in cats

Breed Predilections

  • Domestic shorthair and longhair cats are affected most commonly, but this likely reflects the popularity of these breeds, rather than a true increased likelihood of developing breast tumors as compared to other cat breeds
  • Siamese have twice the risk of developing breast tumors than other cat breeds

Mean Age and Range

  • Mean—10–12 years of age
  • Range—9 months–23 years of age (although most cats are greater than 5 years of age)
  • Siamese tend to develop breast tumors at a younger age and the incidence begins to plateau around 9 years of age

Predominant Sex

  • Females predominate
  • While being intact (that is, capable of reproducing) increases the risk of breast tumors, most cats diagnosed with breast tumors are spayed females
  • 1–5% of breast cancer (mammary carcinoma) occur in male cats

Signs/Observed Changes in the Pet

  • Masses in the breast tissue; masses may be soft or firm; smaller masses often are freely moveable, whereas larger masses may adhere to the underlying abdominal wall
  • Overlying skin can be intact, but frequently is ulcerated
  • Associated nipple may be inflamed, with discharge of clear fluid
  • Any or all glands may be involved; the caudal two glands (near the rear legs) are affected more commonly than the other glands; left and right sides are affected with equal frequency
  • Approximately 50% of affected pets have multiple gland involvement
  • Infiltrated lymphatic vessels—may appear as subcutaneous (that is, under the skin), linear, beaded chains
  • Cats with advanced metastatic disease may have general signs of illness (such as sluggishness [lethargy], lack of appetite [known as “anorexia”], difficulty breathing [known as “dyspnea”])
  • Cats with inflammatory carcinoma may have severe ulceration; reddening of the skin (known as “erythema”); pain; fluid buildup in the ventral abdomen and pelvic limbs (fluid buildup known as “edema”)

Causes

  • Unknown

Risk Factors

  • Compared to intact female cats (those cats capable of reproducing), cats spayed at less than 6 months of age are 11 times less likely to develop breast cancer (mammary carcinoma) and those spayed between 6 and 12 months of age are 7 times less likely to develop breast cancer
  • Genetic—Siamese
  • Administration of progestins (such as medroxyprogesterone acetate)—increased risk of benign and malignant breast tumor development in female and male cats
  • Number of litters a mother cat (known as a “queen”) has not been shown to affect breast tumor development

Treatment

Health Care

  • Surgery is recommended for cats with tumors confined to the breast tissue, with or without involvement of the nearby lymph nodes (known as “regional lymph-node involvement”)
  • Post-operative chemotherapy is recommended after the cat has recovered from surgery
  • Chemotherapy can be used as the only treatment for cats that have tumors that cannot be removed surgically (so-called “inoperable tumors”), have distant spread of the cancer (metastasis), or both
  • Radiation therapy can be considered to improve local control after surgery or to control inoperable tumors and improve the pet’s condition, but not to cure (known as “palliative treatment”)
  • Palliative treatment is recommended for cats with nonoperable tumors or significant metastasis, or when surgery and chemotherapy are declined

Surgery

  • Radical mastectomy of the affected mammary (breast) chain is recommended; this significantly reduces the risk of local tumor recurrence, as well as recurrence in lymph vessels running through the breast tissueTumors in both mammary chains—perform two radical mastectomies, one on each chain (known as “bilateral radical mastectomies), timed usually 2–4 weeks apart
  • Survival time may be increased with bilateral radical mastectomy; however, some studies suggest that unilateral (that is, one-sided) radical mastectomy may be sufficient to effectively control local disease in some pets
  • In cats with advanced metastatic disease, local mastectomy to control signs and improve the pet’s condition, but not to cure (palliative treatment) can be considered to remove an ulcerated or infected tumor

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Chemotherapy—doxorubicin alone or in combination with cyclophosphamideOther chemotherapeutic agents (mitoxantrone, carboplatin, and docetaxel) might have activity
  • Consult with a veterinary oncologist for current chemotherapy recommendations
  • Pain relievers (known as “analgesics”) and antibiotics should be considered for cats with tumors that are painful, ulcerated, or both
  • No available immune response modifier (known as an “immunomodulator,” such as levamisole, bacterial vaccines, and liposomal muramyl peptide) has shown effectiveness
  • Tamoxifen and other selective estrogen receptor modulators have not been evaluated for safety and effectiveness

Follow-Up Care

Patient Monitoring

  • Thorough physical examination—conducted monthly for the first 3 months and then every 2–3 months thereafter; emphasis on checking previous incision line(s), remaining mammary glands, and regional lymph nodes
  • Chest x-rays (radiographs)—three-view radiographs taken every 2 months, to check for spread of the cancer (metastasis) into the lungs

Preventions and Avoidance

  • Spay (ovariohysterectomy)—compared to intact female cats (those cats capable of reproducing), cats spayed at less than 6 months of age are 11 times less likely to develop breast cancer (mammary carcinoma) and those spayed between 6 and 12 months of age are 7 times less likely to develop breast cancer; no obvious protective effect when cats are spayed at greater than 12 months of age

Possible Complications

  • Fluid buildup in the space between the lungs and chest wall (known as “pleural effusion”); life-threatening difficulty breathing (difficulty breathing is known as “dyspnea”)
  • Chemotherapy—reduction of bone-marrow activity (known as “myelosuppression”), resulting in low numbers of red blood cells, white blood cells, and/or platelets; lack of appetite (known as “anorexia”)

Expected Course and Prognosis

  • Most cats die from local recurrence of breast cancer, spread of their cancer (metastasis), or both
  • Tumor size is strongly predictive of prognosis; median survival with tumor diameter greater than 3 cm is 4–6 months after surgery (1–2 months in male cats); median survival with tumor diameter of 2–3 cm, is 1–2 years (5–6 months in male cats); median survival with tumor diameter less than 2 cm is approximately 4.5 years (14 months in male cats)
  • Radical mastectomy significantly reduces the risk for local tumor recurrence; the impact on survival is not as consistent because of the high rate of spread (metastasis) associated with breast cancer in cats
  • For cats with advanced-stage disease treated with chemotherapy alone, response rates are around 50%, with survival times of 6–12 months for cats that have a response to treatment and less than 6 months for cats that do not respond to chemotherapy

Key Points

  • Early detection and aggressive treatment of breast (mammary gland) tumors in cats is very important
  • Many affected pets have advanced disease when first presented for examination by the veterinarian
  • Spay (ovariohysterectomy) at an early age (prior to 6 months) in non-breeding cats has a significant protective effect
  • Given the possible genetic contribution to this disease, particularly in Siamese cats, breeding affected cats is not recommended

Lymphoma

Lymphoma in Cats – Overview

  • Lymphocytes are a type of white blood cell that are formed in lymphatic tissues throughout the body; lymphocytes normally are involved in the immune process
  • Lymphoma is cancer (malignancy) of lymphocytes that usually involves lymph nodes or other lymphatic tissue of the body, but may involve other organs of the body (such as the liver or kidneys)
  • Lymphoma in cats is found in various anatomic locations in the body, including the mediastinum (known as the “mediastinal form of lymphoma”)—the mediastinum is the center portion of the chest that contains the heart and other organs (except for the lungs); the gastrointestinal tract (known as the “alimentary form of lymphoma”); the kidneys (known as the “kidney or renal form of lymphoma”); multiple organs/tissues throughout the body (known as the “multicentric form of lymphoma”); and the spinal cord (known as the “spinal form of lymphoma”)

Signalment/Description of Pet

Species

  • Cats

Breed Predilections

  • Siamese and other Oriental breeds may be more likely to have lymphoma than other cat breeds

Mean Age and Range

  • Mean age of feline leukemia virus (FeLV)-positive cats with lymphoma—3 years
  • Mean age of FeLV-negative cats with lymphoma—7 years
  • Median age of cats with localized lymphoma, outside of the lymph nodes—13 years
  • Most cats with Hodgkin’s-like lymphoma are older than 6 years of age

Signs/Observed Changes in the Pet

  • Depend on anatomic form
  • Mediastinal form (located in the center of the chest)—open-mouthed breathing; coughing; regurgitation; lack of appetite (known as “anorexia”); weight loss; the front part of the chest is very firm and resistant to gentle compression during physical examination
  • Alimentary form (located in the gastrointestinal tract)—lack of appetite (anorexia); weight loss; sluggishness (lethargy); vomiting; constipation; diarrhea; black, tarry stools, due to the presence of digested blood (known as “melena”); frank blood in the stool; thickened intestines or abdominal masses
  • Kidney or renal form—consistent with kidney failure (such as vomiting; lack of appetite [anorexia]; increased thirst [known as “polydipsia”]; increased urination [known as “polyuria”]; and sluggishness [lethargy]); large, irregular kidneys
  • Nasal form (located in the nose or nasal passages)—discharge from the nose (known as “nasal discharge”) or bleeding in the nose and nasal passages (known as “epistaxis” or a “nosebleed”); facial deformity; abnormalities of the eyes; excessive tearing (known as “epiphora”); abnormal breathing sounds; sneezing; lack of appetite (anorexia)
  • Multicentric form (located in multiple organs/tissues throughout the body)—possibly none in early stages; lack of appetite (anorexia), weight loss, and depression with progression of disease; enlargement of lymph nodes throughout the body
  • Spinal form—quickly progressing weakness to partial paralysis in rear legs (known as “posterior paresis”)
  • Cutaneous (skin) lymphoma—itchiness (known as “pruritus); bleeding (hemorrhage); or masses on the skin accompanied by hair loss (hair loss known as “alopecia”)
  • All forms—fever; dehydration; depression; extreme weight loss with muscle wasting (known as “cachexia”) in some pets

Causes

  • Feline leukemia virus infection—pets inconsistently test positive during illness (for example, 85% are positive with the mediastinal form, 45% with the kidney form, 20% with the multicentric form, and 15% with the alimentary (intestinal) forms of lymphoma test positive on FeLV test); older cats with lymphoma are usually FeLV negative, while younger cats are usually FeLV positive

Risk Factors

  • Feline leukemia virus exposure
  • Exposure to environmental tobacco smoke

Treatment

Health Care

  • Outpatient, whenever possible
  • Supportive medical care, if needed depending on clinical signs
  • Fluid therapy, appetite stimulants, and other treatments based on clinical signs
  • Radiation therapy—may be used for localized lymphoma; relapses outside the radiation field are not uncommon
  • Consult a veterinary oncologist for chemotherapy doses, schedules, and to help assess best option(s) for treatment

Activity

  • Normal

Diet

  • No change in most cases; may require dietary change if cat has kidney failure
  • Can add omega-3 (n-3) fatty acids (fish oil origin) to the diet

Surgery

  • To relieve intestinal blockages or obstructions, repair “holes” in the intestinal tract (known as “perforations”) that develop secondarily to the presence of the tumor and to surgically remove individual tumors
  • To obtain biopsy specimens for microscopic examination

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Chemotherapy—used in a combination or sequential protocol; some protocols have induction and maintenance periods
  • Many variations of similar combination chemotherapy exist; they all have similar effectiveness
  • Low-grade intestinal lymphoma can respond to oral chlorambucil and prednisone

Follow-Up Care

Patient Monitoring

  • Physical examination, complete blood count (CBC), and platelet count—before each weekly chemotherapy treatment and one week after each time a new drug is administered, of if concerned about low blood cell counts
  • X-rays (radiographs) or advanced imaging—as necessary, depending on location of primary tumor

Preventions and Avoidance

  • Avoid exposure to or breeding feline leukemia virus–positive cats

Possible Complications

  • Low white blood cell counts (known as “leukopenia”)
  • Generalized bacterial infection (sepsis)
  • Lack of appetite (anorexia)

Expected Course and Prognosis

  • Depends on initial response to chemotherapy, anatomic type, feline leukemia virus status, and tumor burden; overall response rate is 50–70% to treatment
  • Median survival with prednisone alone—1.5–2 months
  • Median survival with combination chemotherapy (COP or CHOP)—6–9 months
  • Mediastinal form (located in the center of the chest)—about 10% of affected pets with live more than 2 years
  • Median survival with alimentary form (located in the gastrointestinal tract)—8 months
  • Median survival with peripheral multicentric form (located in multiple organs/tissues: “peripheral” refers to tissues away from the center of the body)—23.5 months
  • Median survival with kidney form—if FeLV-negative, 11.5 months; if FeLV-positive, 6.5 months
  • Median survival with nasal form—1.5–2.5 years with radiation and chemotherapy; chemotherapy may not improve survival over radiation alone
  • Cats with Hodgkin’s-like lymphoma can do well for extended periods of time (months to years), even without treatment

Key Points

  • A treatment protocol should be established that fits the pet and the owner’s lifestyle
  • Side effects of chemotherapy are treatable and should be addressed promptly
  • Goal is to induce remission and achieve a good quality of life for pets for as long as possible
  • More than 80% of pet owners are pleased with their cat’s quality of life during chemotherapy

Inflammation of the Pancreas (Pancreatitis) in Cats

Inflammation of the Pancreas (Pancreatitis) in Cats – Overview

  • The pancreas is an organ of the body, located near the upper small intestine; the pancreas produces insulin to regulate blood sugar and produces digestive enzymes involved in digestion of starches, fats, and proteins in the animal’s diet; the digestive enzymes are delivered to the upper small intestine through the pancreatic duct
  • “Pancreatitis” is inflammation of the pancreas
  • Sudden (acute) pancreatitis—inflammation of the pancreas that occurs abruptly, with little or no permanent damage to the pancreas
  • Long-term (chronic) pancreatitis—continuing inflammation of the pancreas that is accompanied by irreversible damage to the pancreas
  • “Edematous pancreatitis” is characterized by fluid buildup in the interstitium (small spaces between tissues or parts of the pancreas) and mild inflammation with neutrophils and lymphocytes (two types of white-blood cells); the pet generally recovers rapidly
  • “Necrotizing pancreatitis” is inflammation of the pancreas characterized by bleeding (hemorrhage) and areas of death of tissues (known as “necrosis,” thus the name “necrotizing pancreatitis”); it usually is a severe and prolonged disease and many affected pets die

Breed Predilections

  • Siamese (cat)

Mean Age and Range

  • Mean age for sudden (acute) pancreatitis in cats is 7.3 years

Signs/Observed Changes in the Pet

  • Dogs—predominantly gastrointestinal tract signs (such as vomiting, diarrhea)
  • Cats—vague, non-specific signs that generally do not localize problem to the pancreas
  • Sluggishness (lethargy), depression, lack of appetite (known as “anorexia”)—common in dogs and cats
  • Vomiting—common in dogs, less common in cats
  • Diarrhea—more frequently seen in dogs than in cats
  • Weight loss—common in cats
  • Dogs may exhibit abdominal pain
  • Yellowish discoloration to gums and moist tissues of the body (known as “jaundice” or “icterus”)—common in dogs and cats
  • Dehydration—common; due to gastrointestinal losses of fluid
  • Mass lesions may be felt during physical examination in both dogs and cats.
  • Fever—common in dogs; both fever and low body temperature (known as “hypothermia”) reported in cats
  • Less common systemic abnormalities include severe breathing difficulties (known as “respiratory distress”), bleeding disorders, and irregular heartbeats (known as “cardiac arrhythmias”)

Causes

  • Usually unknown; possibilities include the following:
  • Nutritional factors (such as an increase in lipoprotein [complexes of lipid and protein] concentration in the blood [known as “hyperlipoproteinemia”])
  • Pancreatic trauma or lack of blood flow (known as “ischemia”) to the pancreas
  • Duodenal reflux (a condition in which contents in the upper small intestine [duodenum] move backward)
  • Drugs or toxins
  • Pancreatic duct blockage or obstruction
  • High levels of calcium in the blood (known as “hypercalcemia”)
  • Infectious diseases—toxoplasmosis, feline infectious peritonitis (FIP)
  • Extension of inflammation from the liver and bile duct system or intestines in the cat

Risk Factors

  • Breed—dog: miniature schnauzer, miniature poodle, cocker spaniel; cat: Siamese
  • Obesity in dogs
  • Another disease (such as sugar diabetes [diabetes mellitus]; increased levels of steroids produced by the adrenal glands [known as “hyperadrenocorticism” or “Cushing’s syndrome”]; long-term [chronic] kidney failure, and cancer) in dogs
  • Recent administration of certain drugs
  • Liver (hepatic) or gastrointestinal tract inflammation in cats

Treatment
Health Care

  • Inpatient medical management
  • Aggressive intravenous (IV) fluid therapy
  • Fluid therapy goals—correct low circulating blood volume (known as “hypovolemia”) and maintain pancreatic circulation
  • A balanced electrolyte solution (such as lactated Ringer’s solution [LRS]) is the first-choice for providing hydration
  • May need colloids; colloids are fluids that contain larger molecules that stay within the circulating blood to help maintain circulating blood volume, examples are dextran and hetastarch
  • Following replacement of fluid deficits, give additional fluids to match maintenance requirements and ongoing losses
  • Potassium chloride (KCl) supplementation usually needed, because potassium is lost from the body in the vomit

Activity

  • Restrict

Diet

  • Continue to feed by mouth, unless vomiting is difficult to control; feeding maintains the integrity of the intestinal lining and minimizes bacterial invasion from the intestines and into the body
  • Pets with intermittent vomiting should be treated with drugs to control nausea and vomiting (known as “antiemetics”), such as metoclopramide or phenothiazines
  • Tube feeding into the jejunum (the middle section of the small intestine) allows feeding into the intestines (known as “enteral feeding”), while allowing the pancreas to rest
  • Withhold all food and water by mouth (known as “NPO”) in pets with persistent vomiting for the shortest time possible; when no vomiting has occurred for 4–6 hours, offer small volumes of water; if tolerated, begin small, frequent feedings of a carbohydrate (such as boiled rice); gradually introduce a protein source of high biologic value (such as cottage cheese or lean meat)
  • Avoid high-protein and high-fat diets
  • Pets needing extended time without food and water by mouth (NPO) may require tube feeding into the jejunum or intravenous feeding (known as “total parenteral nutrition”)

Surgery

  • May need surgery to remove localized accumulations of fluid (known as “pseudocysts”), abscesses, or areas of dead (necrotic) tissue seen with necrotizing pancreatitis (inflammation of the pancreas characterized by bleeding and areas of death of tissues)
  • May need surgical exploration of the abdomen and biopsy of the pancreas to confirm pancreatitis and/or to rule out other diseases not involving the pancreas
  • Bile-duct blockage outside of the liver (known as “extrahepatic biliary obstruction”) from pancreatitis requires surgical correction

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Steroids are indicated only for the treatment of shock
  • Drugs that act on the vomiting center of the brain to control nausea and vomiting (known as “centrally acting antiemetics”) are indicated with vomiting that is difficult to control—metoclopramide, chlorpromazine, or prochlorperazine
  • Maropitant (Cerenia)—medication to control nausea and vomiting (antiemetic); useful in controlling sudden (acute) vomiting in dogs
  • Antibiotics, if evidence of sepsis (presence of pus-forming bacteria and their poisons in the blood or tissues)—penicillin G, ampicillin, and enrofloxacin
  • Pain relievers (known as “analgesics”) to relieve abdominal pain, such as buprenorphine

Follow-Up Care
Patient Monitoring

  • Evaluate hydration status closely during first 24 hours of therapy; twice daily check physical examination; body weight; packed cell volume (PCV, a means of measuring the percentage volume of red-blood cells as compared to the fluid volume of blood) and total solids (a quick laboratory test that provides general information on the level of protein in the fluid portion of the blood); and blood urea nitrogen (BUN) and urine output to monitor the kidneys and hydration status
  • Evaluate the effectiveness of fluid therapy after 24 hours, and adjust flow rates and fluid composition accordingly; repeat blood tests (serum biochemistries) to assess electrolyte/acid–base status
  • Repeat plasma enzyme concentrations (pancreatic-lipase immunoreactivity [PLI] assay, a test that determines the levels of lipase, a pancreatic enzyme) after 7 days, to evaluate the status of the inflammation of the pancreas
  • Watch closely for complications involving a variety of organ systems; perform appropriate diagnostic tests as needed
  • Gradually taper fluids down to maintenance requirements, if possible
  • Maintain feeding by mouth or into the jejunum (enteral nutrition)
  • Reassess and correct ongoing low serum cobalamin (Vitamin B12) concentrations

Preventions and Avoidance

  • Weight reduction, if obese
  • Avoid high-fat diets
  • Avoid drugs that may increase the risk of inflammation of the pancreas (pancreatitis)

Possible Complications

  • Failed response to supportive therapy
  • Life-threatening associated conditions

Expected Course and Prognosis

  • Good for most pets with edematous pancreatitis (inflammation of the pancreas characterized by fluid buildup in the interstitium and mild inflammation with neutrophils and lymphocytes [two types of white-blood cells]); these pets usually respond to appropriate symptomatic therapy
  • More guarded to poor for pets with necrotizing pancreatitis (inflammation of the pancreas characterized by bleeding [hemorrhage] and areas of death of tissues [necrosis]) and systemic conditions

Key Points

  • Sudden (acute) pancreatitis—inflammation of the pancreas that occurs abruptly, with little or no permanent damage to the pancreas
  • Long-term (chronic) pancreatitis—continuing inflammation of the pancreas that is accompanied by irreversible damage to the pancreas
  • Need for extended hospitalization
  • Diagnosis and treatment can be expensive
  • Possible complications include lack of response to supportive therapy and life-threatening conditions

Obesity in Cats

Obesity in Cats – Overview

  • An excess of body fat, frequently resulting in adverse health effects
  • Even a moderate excess in body fat can increase incidence of disease (known as “morbidity”) and reduce lifespan

Mean Age and Range

  • All ages, with the greatest prevalence (nearly 50%) in middle-aged cats

Predominant Sex

  • Most common in neutered, indoor pets

Signs/Observed Changes in the Pet

  • Weight gain
  • Exercise intolerance may be reported
  • Excess body fat and high body condition score or BCS (estimate of weight status [under- or overweight] as compared to normal weight)

Causes

  • Obesity is caused by an imbalance between calorie or energy intake and calorie or energy expenditure, with intake exceeding expenditure
  • Neutering, decreased opportunities for activity, and age can reduce expenditure of energy
  • Overfeeding of high calorie foods, frequently alternating foods, and provision of excess treats contribute to excess calorie or energy intake
  • Low levels of thyroid hormone (known as “hypothyroidism”), insulin-secreting tumor (known as an “insulinoma”), or high levels of steroids produced by the adrenal glands (known as “hyperadrenocorticism” or “Cushing’s syndrome”) are infrequent causes of obesity

Treatment
Health Care

  • Weight loss, induced by reducing calorie intake below calorie or energy expenditure
  • Successful weight loss also requires long-term maintenance of the reduced weight
  • Weight loss and maintenance of reduced weight depend on changes in the way the owner feeds and interacts with the pet
  • The owner should assess and monitor the body condition score (estimate of weight status [under- or overweight] as compared to normal weight) of his or her pet; your pet’s veterinarian will provide information on assessing BCS

Activity

  • Calorie or energy restriction results in compensatory decreases in basal energy expenditure or metabolism; increased activity helps compensate for this decrease in metabolism and provides alternate opportunities for owner-pet interactions
  • Leash walking for dogs and trained cats—at least 15 minutes twice daily
  • Activities such as “fetch,” interactive toys for cats, or playing with a laser light
  • Food balls—built to hold treats or kibbles and randomly release them while the dog or cat plays; food used in the ball must be included as part of the daily calorie allowance

Diet

  • Get written instructions regarding specific amounts to provide, using the agreed upon reducing diet (a “cup” of food refers to an 8-oz measuring cup); measure food carefully to ensure appropriate amount is being fed
  • Protein—increased dietary protein facilitates loss of body fat, while minimizing loss of lean body mass (LBM), which is the metabolically active tissue—preserving LBM should help with long-term weight control by maintaining a higher resting energy requirement; protein also stimulates metabolism, increases energy expenditure, and contributes to the feeling of being full or satisfied (known as “satiety”)
  • Fiber—dietary fiber provides little dietary energy, so it helps reduce total calories in the diet; fiber also stimulates intestinal metabolism and energy utilization, and contributes to the feeling of being full or satisfied (satiety)
  • Other dietary factors that may aid in weight management—carnitine, compound necessary for fat metabolism; isoflavones, stimulate energy metabolism and support lean body mass
  • Fat—calorie or energy dense, so low-fat diets are lower in energy
  • Calories should be restricted, without excessive restriction of essential nutrients; a low-calorie therapeutic diet with an increased nutrient-to-calorie ratio is recommended for weight loss
  • Amount fed should target a 1–2% loss in body weight per week; faster weight loss may increase loss of lean body mass and stimulate weight rebound once weight loss is achieved
  • High moisture diets can be used to reduce calories per serving; this approach appears to be more effective for cats versus dogs, as cats tend to control their intake based on volume
  • If the client is not willing to use a therapeutic diet, severe calorie restriction should be avoided; a food diary can be used to record current intake over 3–7 days—subsequently, the pet should be fed 10–20% less than it previously received
  • Treats are often part of the owner-pet bond; complete avoidance of treats is a hurdle to compliance with weight loss programs—instead, offer a “treat allowance” of 10% of the daily calories and use low-calorie treats suitable for dogs or cats, as directed by your pet’s veterinarian

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Dirlotapide (Slentrol, Pfizer Animal Health)—approved only for use in dogs; can cause decreased appetite sufficient to lead to weight loss; use with a diet formulated for weight loss; appetite and weight will rebound after discontinuing dirlotapide; talk to your pet’s veterinarian about a feeding plan to avoid rebound weight gain
  • Mitratapide has a similar mechanism of action; use limited to a single course of treatment

Follow-Up Care
Patient Monitoring

  • Frequent communication is important during the weight management program
  • Telephone call from clinic to the owner to address any minor questions and to reinforce the importance of the program
  • Pet should be weighed in the clinic on a monthly basis; if needed, adjustments in food allowance guidelines should be made at this time
  • Once the pet has achieved an ideal body condition score (estimate of weight status [under- or overweight] as compared to normal weight) guidelines should be provided for weight maintenance; continue to measure food, monitor BCS or body weight, and adjust food allowance as needed to maintain the goal weight

Preventions and Avoidance

  • Monitor food intake, weight, and body condition score (estimate of weight status [under- or overweight] as compared to normal weight) throughout life to prevent weight gain and obesity
  • Maintain a healthy diet and reduce caloric intake if pet starts gaining weight (even small weight gains of 1–2 pounds can be significant in small- and medium-size dogs and in cats)

Possible Complications

  • Obesity leads to increased risk for diseases (such as osteoarthritis, diabetes mellitus) or shortened lifespan

Key Points

  • Obesity leads to increased risk for diseases (such as osteoarthritis, diabetes mellitus) or shortened lifespan
  • Weight loss and maintenance of reduced weight depend on changes in the way the owner feeds and interacts with the pet
  • Monitor food intake, weight, and body condition score (estimate of weight status [under- or overweight] as compared to normal weight) throughout life to prevent weight gain and obesity
  • Maintain a healthy diet and reduce caloric intake if pet starts gaining weight (even small weight gains of 1–2 pounds can be significant in small- and medium-size dogs and in cats)

Megacolon

Megacolon – Overview

  • “Mega-” refers to large or oversized; “colon” is another term for the large intestine
  • “Megacolon” is a condition of persistent, increased large-intestine diameter associated with long-term (chronic) constipation/obstipation and low-to-absent movement of the large intestines (known as “colonic motility”)
  • “Constipation” is infrequent, incomplete, or difficult defecation with passage of hard or dry bowel movement (feces)
  • “Obstipation” is constipation that is difficult to manage or does not respond to medical treatment, caused by prolonged retention of hard, dry bowel movement (feces); defecation is impossible in the pet with obstipation

Breed Predilections

  • Some evidence for increased risk of having megacolon in Manx cats as compared to other cat breeds

Mean Age and Range

  • Acquired (condition that develops sometime later in life/after birth) megacolon—none
  • Idiopathic megacolon (enlarged large intestine of unknown cause)—middle-aged to old cats (mean age, 4.9 years; range, 1–15 years)

Signs/Observed Changes in the Pet

  • Acquired (condition that develops sometime later in life/after birth) megacolon—signs may be sudden (acute) or long-term (chronic)
  • Idiopathic megacolon (enlarged large intestine of unknown cause)—typically a long-term (chronic) or recurrent problem; signs often present for months to years
  • Constipation/obstipation (constipation that is difficult to manage or does not respond to medical treatment)
  • Painful defecation or straining to defecate (known as “tenesmus”) with small or no fecal volume
  • Hard, dry feces
  • Infrequent defecation
  • Small amount of diarrhea (often with mucus) may occur after prolonged painful defecation or straining to defecate (tenesmus)
  • Occasional vomiting, lack of appetite (known as “anorexia”), and/or depression
  • Weight loss
  • Enlarged colon with hard bowel movement (feces) may be detected on physical examination
  • Rectal examination may indicate an underlying (obstructive) cause and confirms the presence of hardened bowel movement in the large intestine (colon) or rectum (condition known as “fecal impaction”)
  • Dehydration
  • Scruffy, unkempt hair coat

Causes

  • Idiopathic megacolon (enlarged large intestine of unknown cause)—cats
  • Mechanical blockage or obstruction of the passage of bowel movement (feces)—pelvic fracture; foreign body or improper diet (especially bones); abnormal narrowing of the colon or rectum (known as a “stricture”); prostate disease; condition in which the muscles supporting the rectum weaken and separate, allowing the rectum and/or bladder to slide under the skin and causing swelling in the area of the anus (known as a “perineal hernia”); cancer; birth defect in which the anus or rectum does not have an opening (known as “anal atresia” or “rectal atresia,” respectively)
  • Causes of difficulty defecating (dyschezia)—disease of the anus and/or rectum (such as inflammation of the anal sacs [known as “anal sacculitis”]; anal sac abscess; one or multiple draining tracts around the anus (known as “perianal fistulae”); inflammation of the lining of the rectum [known as “proctitis”]); trauma (fractured pelvis, fractured limb, dislocated hip, bite wound or laceration in the tissue around the anus, perineal [area between the anus and external genitalia] abscess)
  • Metabolic disorders—low levels of potassium in the blood (known as “hypokalemia”), severe dehydration
  • Various medications—examples include vincristine, barium, antacids, sucralfate, anticholinergics (used as preanesthetics or to treat diarrhea, such as atropine)
  • Nervous system and/or muscular disease—congenital (present at birth) abnormalities of the spine (especially Manx cats); paralysis of the rear legs (known as “paraplegia”); spinal cord disease; intervertebral disk disease; abnormal function of the autonomic nervous system (known as “dysautonomia”); sacral nerve disease; sacral nerve trauma (such as a tail fracture/pull injury); trauma to nerves to the large intestine

Risk Factors

  • Pain involving the rectum and/or anus and conditions (such as pelvic and limb fractures or diseases of the nerves and/or muscles) leading to inability to posture to defecate
  • Prior pelvic fractures
  • Possible association with low physical activity and obesity
  • Perineal hernias; a “perineal hernia” develops when the muscles supporting the rectum weaken and separate, allowing the rectum and/or bladder to slide under the skin and causing swelling in the area of the anus

Treatment
Health Care

  • Inpatient medical management; surgery may be indicated, if recurrent or severe problem
  • Medical treatment—restore normal hydration, followed by anesthesia and manual evacuation of the colon using warm water enemas, water-soluble jelly, and gentle extraction of feces with a gloved finger or sponge forceps
  • Continue long-term therapy at home
  • Most pets require fluids to correct dehydration
  • Continue fluid support until the pet is willing to eat and drink

Activity

  • Encourage activity and exercise
  • Restricted activity indicated in the postoperative period, if surgery is performed

Diet

  • Many pets require a low-residue-producing diet; bulk-forming fiber diets can worsen or lead to recurrence of megacolon
  • A high-fiber diet is occasionally helpful
  • A maintenance-type diet can be supplemented with products such as Metamucil or pumpkin-pie filler

Surgery

  • An underlying blockage or obstructive cause requires surgical correction
  • Avoid enema administration/colonic evacuation prior to surgical procedure to remove part of the colon (known as a “subtotal colectomy”)
  • Surgical removal of a section of the colon, with connection of the ends of the remaining sections of the intestines (known as “ileorectal or colorectal resection and anastomosis”)—treatment of choice for idiopathic megacolon (enlarged large intestine of unknown cause) that does not respond to medical management
  • Surgical removal of the colon (known as a “colectomy”) may be required with obstructive megacolon caused by irreversible changes in movement of the large intestines (colonic motility)

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Can improve large intestinal movement (colonic motility) in less severe cases with cisapride, a gastrointestinal prokinetic drug; “gastrointestinal prokinetic drugs” are medications that improve the propulsion of contents through the stomach and intestines
  • Stool softeners (such as lactulose) are recommended in conjunction with cisapride and diet
  • Broad-spectrum antibiotics are recommended prior to emptying the colon and rectum of dry, hard bowel movement (feces) and during the time immediately surrounding surgery, if surgery is elected
  • Docusate sodium can be used as a stool softener in place of lactulose

Follow-Up Care
Patient Monitoring

  • Following surgical removal of part of the large intestine (colon) with connection of the ends of the remaining sections of the intestines (known as “colonic resection and anastomosis”)—for 3–5 days check for signs of splitting open or bursting along the incision line (known as “dehiscence”) and inflammation of the lining to the abdomen (known as “peritonitis”)
  • Clinical deterioration warrants tapping the abdomen (known as “abdominocentesis”) and/or flushing the abdomen (known as “peritoneal lavage”) to detect leakage of intestinal contents through the incision site

Preventions and Avoidance

  • Repair pelvic fractures that narrow the pelvic canal
  • Avoid exposure to foreign bodies and feeding bones

Possible Complications

  • Recurrence or persistence—most common
  • Potential surgical complications include inflammation of the lining of the abdomen (peritonitis), persistent diarrhea, abnormal narrowing of the large intestine (stricture formation), and recurrence of obstipation (constipation that is difficult to manage or does not respond to medical treatment)
  • Abnormal opening or hole in the large intestines (known as a “perforation”)

Expected Course and Prognosis

  • Historically, medical management has been unrewarding
  • Cisapride appears to improve the prognosis with medical management in some pets, but may not suffice in severe or long-standing cases
  • Postoperative diarrhea—expected; typically resolves within 6 weeks (80% of cats with idiopathic megacolon [enlarged large intestine of unknown cause] undergoing surgical removal of part of the colon [subtotal colectomy]), but can persist for several months
  • Surgical removal of part of the colon (subtotal colectomy) is well tolerated by cats; constipation recurrence rates are typically low

Key Points

  • In idiopathic megacolon (enlarged large intestine of unknown cause) or with severe colonic injury, medical treatment often is lifelong and can be frustrating
  • Recurrence is common
  • Surgical removal of part of the colon (subtotal colectomy) is indicated, if medical treatment fails

Chronic Diarrhea in Cats

Chronic Diarrhea in Cats – Overview

  • A change in the frequency, consistency, and volume of bowel movement (feces) for more than 3 weeks or with a pattern of episodic recurrence
  • Can be either small bowel (small intestine) or large bowel (large intestine or colon) diarrhea

Signs/Observed Changes in the Pet

  • Underlying disease process determines clinical signs

Small Bowel Diarrhea (Involves the Small Intestines)

  • Larger volume of bowel movement (feces) than normal
  • Frequency of defecation is mild to moderately above normal (2–4 times per day)
  • Weight loss
  • Increased appetite (known as “polyphagia”) in cases with abnormal digestion or absorption of food (known as “maldigestion” or “malabsorption,” respectively) or increased levels of thyroid hormone (known as “hyperthyroidism”)
  • May have black, tarry stools (due to the presence of digested blood; condition known as “melena”); no mucus or red blood in the bowel movement (presence of red blood in the bowel movement known as “hematochezia”)
  • Little to no evidence of painful defecation or straining to defecate (known as “tenesmus”) or difficulty in defecating (known as “dyschezia”)
  • May have excessive gas formation in the stomach or intestines (known as “flatulence”) and rumbling or gurgling sounds caused by movement of gas in the intestinal tract (known as “borborygmus”)
  • Vomiting—variable
  • Poor body condition with some causes of long-term (chronic) diarrhea
  • Dehydration—variable
  • Thickened intestines, abdominal fluid, and enlarged abdominal lymph nodes may be felt by your pet’s veterinarian

Large Bowel Diarrhea (Involves the Large Intestines or Colon)

  • Smaller volume of bowel movement (feces) per defecation than normal
  • Frequency of defecation significantly higher than normal (greater than 4 times per day)
  • No weight loss
  • Often mucus or red blood in the bowel movement (hematochezia); no evidence of black, tarry stools (melena)
  • Painful defecation or straining to defecate (tenesmus) and urgency to defecate
  • Difficulty defecating (dyschezia) with rectal or lower colonic disease
  • Excessive gas formation in the stomach or intestines (known as “flatulence”) and rumbling or gurgling sounds caused by movement of gas in the intestinal tract (known as “borborygmus”)—variable
  • Vomiting—variable
  • Body condition more typically normal
  • Dehydration—uncommon
  • Thickened intestines may be felt by your pet’s veterinarian

Causes

  • Inflammatory bowel disease (IBD)—various types, including lymphoplasmacytic enterocolitis, granulomatous enteritis, eosinophilic enteritis/hypereosinophilic syndrome, and idiopathic inflammatory colitis
  • Tumor or cancer—lymphoma, adenocarcinoma, mast cell tumor, and polyps
  • Blockage or obstruction of the small or large intestines—tumor or cancer, foreign body, IBD, folding of one segment of the intestine into another segment (known as “intussusception”), and abnormal narrowing of the intestines (known as a “stricture”)
  • Metabolic disorders—increased levels of thyroid hormone (known as “hyperthyroidism”), kidney disease, liver disease, diabetes mellitus (“sugar diabetes”)
  • Poisons
  • Side effect of medications
  • Parasites—Giardia, Toxoplasma, roundworms (Toxocara cati, Toxascaris leonina), hookworms (Ancylostoma), Cryptosporidium, Cystoisospora, Tritrichomonas
  • Bacterial infections—Escherichia coli, Campylobacter, Salmonella, Yersinia, and Clostridium perfringens
  • Viral infections—feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), and feline infectious peritonitis (FIP)
  • Fungal diseases—histoplasmosis, aspergillosis
  • Non-inflammatory causes of abnormal absorption of food (malabsorption)—dilation of the lymphatic vessels (known as “lymphangiectasia”); condition in which a high number of bacteria are found in the upper small intestine (known as “small intestinal bacterial overgrowth”); diarrhea and other signs caused by absence of a long section of small intestine, usually because of surgical removal (condition known as “short-bowel syndrome”); and ulcers in the upper small intestines (known as “duodenal ulcers”)
  • Abnormal digestion of food (maldigestion)—liver disease and syndrome caused by inadequate production and secretion of digestive enzymes by the pancreas (known as “exocrine pancreatic insufficiency”)
  • Diet—dietary sensitivity, dietary indiscretion (that is, eating substances that should not be eaten), and diet changes
  • Congenital (present at birth) anomalies—short colon; condition in which blood vessels allow blood to flow abnormally between the portal vein (vein that normally carries blood from the digestive organs to the liver) and the body circulation without first going through the liver (known as a “portosystemic shunt”)

Risk Factors

  • Dietary changes and feeding poorly digestible or high-fat diet

Treatment
Health Care

  • Often must be specific for the underlying cause to be successful
  • When no definitive diagnosis is possible, treatment with dietary management and metronidazole sometimes results in clinical improvement
  • Fluid therapy for dehydration
  • Correct electrolyte (such as sodium, potassium, chloride) and acid–base imbalances

Diet

  • A lower-fat, novel protein and carbohydrate (a protein and carbohydrate to which the pet has never been exposed) diet or fiber-supplemented diet may be beneficial; feed for 3–4 weeks; may resolve diarrhea due to dietary intolerance or allergy
  • Food should be highly digestible

Surgery

  • Biopsy of the stomach, small intestine, and/or large intestine
  • Exploratory surgery of the abdomen and surgical biopsy

Medications

  • Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive
  • Medications vary, depending on underlying cause

Follow-Up Care
Patient Monitoring

  • Fecal volume and character, frequency of defecation, and body weight
  • Recheck for intestinal parasites

Preventions and Avoidance

  • Depend on underlying cause

Possible Complications

  • Dehydration
  • Poor body condition
  • Fluid buildup in the abdomen (known as “abdominal effusion”) with intestinal cancer (adenocarcinoma)

Expected Course and Prognosis

  • Depend on underlying cause
  • Resolution usually occurs gradually with treatment; if diarrhea does not resolve, consider re-evaluating the diagnosis

Key Points

  • Complete resolution of signs is not always possible, despite a correct diagnosis and proper treatment
  • Some causes of long-term (chronic) diarrhea result in actual changes to the lining of the intestines that may require many months to resolve or that may not resolve.