Kidney Failure in Pets

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 for Kidney Failure in Animals

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 for pets Kidney Failure

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 for Kidney Failure in pets

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