Ethylene Glycol (Antifreeze) Poisoning

Ethylene Glycol (Antifreeze) Poisoning – An Overview

  • Results from ingesting substances containing ethylene glycol (such as antifreeze)
  • Common in small animals (such as dogs)
  • Highest fatality rate of all poisons
  • Higher likelihood of pet having ethylene glycol (antifreeze) poisoning in colder areas, where antifreeze use is more common

Signalment/Description of Pet

Mean Age and Range

  • Any age is susceptible
  • Mean—3 years of age

Signs/Observed Changes in Pet

  • Signs are dependent on the amount of ethylene glycol (antifreeze) ingested
  • Almost always sudden (acute)
  • Signs caused by ethylene glycol itself and its toxic metabolites (frequently fatal); “metabolites” are substances produced by the body’s chemical processes as it breaks down the ethylene glycol
  • Early signs—seen from 30 minutes to 12 hours after ingestion of ethylene glycol in dogs; nausea and vomiting; mild to severe depression; wobbly, incoordinated or “drunken” appearing gait or movement (known as “ataxia”) and knuckling; twitching muscles; short, rapid movements of the eyeball (known as “nystagmus”); head tremors; decreased withdrawal reflexes and righting ability; increased urination (known as “polyuria”) and increased thirst (known as “polydipsia”)
  • Dogs—with increasing depression, the pet drinks less but increased urination (polyuria) continues, resulting in dehydration; central nervous system signs lessen transiently after approximately 12 hours, but return later
  • Production of only small amounts of urine (known as “oliguria”) often develop in dogs 36–72 hours after ingestion of ethylene glycol (antifreeze);lack of production of urine (known as “anuria”) is seen 72–96 hours after ingestion of ethylene glycol—if untreated
  • May note severely low body temperature (known as “severe hypothermia”)
  • Severe sluggishness (lethargy) or coma
  • Seizures
  • Lack of appetite (known as “anorexia”)
  • Vomiting
  • Oral ulcers
  • Salivation or drooling
  • Kidneys—often swollen and painful

Causes

  • Ingestion of ethylene glycol, the principal component (95%) of most antifreeze solutions

Risk Factors

  • Access to ethylene glycol—widespread availability; somewhat pleasant taste; small minimum lethal dose (in other words, ingestion of a small amount can kill a pet); lack of public awareness of toxicity of ethylene glycol–containing antifreeze

Treatment

Health Care

  • Dogs—usually outpatient if presented to veterinarian under 5 hours from the time of ingestion and treated with fomepizole; inpatient if presented to veterinarian more than 5 hours after the time of ingestion for intravenous fluids to correct dehydration, increase blood flow to the tissues, and promote production of urine (known as “diuresis”)
  • Goals—prevent absorption of ethylene glycol into the body; increase excretion or removal of ethylene glycol from the body; prevent chemical processing (metabolism) of ethylene glycol by the body to toxic compounds
  • Induction of vomiting and flushing of the stomach (known as “gastric lavage”) with administration of activated charcoal are not recommended, unless they can be performed in the first 30 minutes following ingestion, due to the rapid absorption of ethylene glycol
  • Intravenous fluids—correct dehydration, increase blood flow to the tissues, and promote production of urine (diuresis); accompanied by administration of bicarbonate (given slowly intravenously) to correct metabolic acidosis (condition in which the pH of the body is too low)
  • If the pet develops excess levels of urea and other nitrogenous waste products in the blood (known as “uremia” or “azotemia”) and kidney failure characterized by production of small amounts of urine (oliguria) in dogs—most of the ethylene glycol has been metabolized; little benefit from treatment specifically designed for ethylene glycol poisoning; correct fluid, electrolyte, and acid–base disorders; promote production of urine (diuresis); medications to induce production and elimination of urine (known as “diuretics”; particularly mannitol) may help; peritoneal dialysis (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) may be useful; may need extended treatment (several weeks) before kidney function is reestablished

Activity

  • Avoid stress and excitement as these could make nervous system signs (hyperreflexia or seizures) worse

Diet

  • Suddenly (acutely) affected pet—do not feed
  • Recovering or convalescent pet—bland diet for several days to allow recovery from gastrointestinal problems

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.

  • Fomepizole (4-methyl pyrazole; Antizol-Vet®)
  • Ethanol, propylene glycol, and 1,3-butanediol—effectively inhibit ethylene glycol metabolism; may cause central nervous system depression; even in early stages of ethylene glycol (antifreeze) poisoning, requires hospitalization for approximately 3 days; constant intravenous (IV) infusion (ethanol and fluids); continuous monitoring for breathing and acid–base status

Follow-Up Care

Patient Monitoring

  • Bloodwork to monitor the kidneys (such as blood urea nitrogen [BUN]), acid–base status, and urine output—monitored daily for the first few days
  • Monitor urine pH to determine response to treatment

Preventions and Avoidance

  • Increasing awareness of the toxicity of ethylene glycol (found in most brands of antifreeze)—help prevent exposure; earlier treatment of pets
  • Use new antifreeze products, containing propylene glycol (relatively non-toxic)

Possible Complications

  • Without excess levels of urea and other nitrogenous waste products in the blood (azotemia)—usually no complications
  • Urine concentrating ability—may be impaired with excess levels of urea and other nitrogenous waste products in the blood (azotemia); pets recover
  • Death

Expected Course and Prognosis

  • Untreated—kidney failure characterized by the production of only small amounts of urine (oliguria) is seen in dogs at 36–72 hours after ingestion of ethylene glycol; lack of production of urine (anuria) is seen by 72–96 hours following ingestion
  • Dogs treated less than 5 hours following ingestion of ethylene glycol—prognosis is excellent with fomepizole treatment
  • Dogs treated up to 8 hours following ingestion of ethylene glycol—most recover
  • Dogs treated up to 36 hours following ingestion of ethylene glycol—may benefit from prevention of the body’s chemical processing (metabolizing) of any remaining ethylene glycol
  • If a large quantity of ethylene glycol is ingested, prognosis is poor, unless treated within 4 hours of ingestion
  • Pets with excess levels of urea and other nitrogenous waste products in the blood (azotemia) and kidney failure characterized by the production of only small amounts of urine (oliguria)—prognosis poor; almost all of the ethylene glycol will have been chemically processed by the body (metabolized) to toxic metabolites

Key Points

  • Ethylene glycol poisoning results from ingesting substances containing ethylene glycol (such as antifreeze)
  • Signs are dependent on the amount of ethylene glycol ingested
  • Ethylene glycol is readily available in many brands of antifreeze; it has a somewhat pleasant taste that attracts pets to ingest it; ethylene glycol has a small minimum lethal dose (in other words, ingestion of a small amount can kill a pet)
  • The public needs to be aware of toxicity of ethylene glycol–containing antifreeze; people should take precautions to safeguard their pets and other pets from potential sources of ethylene glycol

Chocolate Poisoning

Chocolate Poisoning – An Overview

  • Sudden (acute) gastrointestinal, nervous system, and heart problems caused by excessive intake of chemicals (known as methylxanthine alkaloids, such as theobromine and caffeine) present in chocolate and cocoa bean hulls, used for mulch
  • Dogs are poisoned most frequently based on their non-selective appetite, their access to chocolate or chocolate-containing products, and their ability to consume large amounts of chocolate
  • Other species may be affected, but they have a more limited access to chocolate and cocoa bean hull mulch than dogs; cocoa bean hulls may be a source of poisoning in horses and poultry
  • Theobromine is the chemical that is in the highest concentration of methylxanthines in chocolate products and in cocoa bean hull mulch; caffeine is in a much lower concentration in these products
  • Theobromine has a longer half-life in dogs than in people, meaning that it stays in the dog’s body for a longer time period than it does in people
  • Cocoa bean hull mulch is an increasingly popular product for using around gardens; it is composed of the shells (or hulls) of the cocoa bean and is produced during processing of the bean for chocolate

Signalment/Description of Pet

  • Small dogs—may be more at risk (amount of chocolate available compared to dog’s body weight)
  • Puppies and young dogs—may be more likely to ingest large amounts of unusual foods, such as chocolate or chocolate-containing foods, or cocoa bean hull mulch

Signs/Observed Changes in Pet

  • Signs are seen after recent chocolate or cocoa bean hull ingestion (family may find evidence of chewed containers or remnants of packaging from chocolate or chocolate-containing products
  • Vomiting and diarrhea—often the first reported signs; occur 2–4 hours after ingestion
  • Early restlessness and increased activity or nervousness
  • Frequent urination (known as “polyuria”)—may result from diuretic action of chemicals in chocolate
  • Blood in the urine (known as “hematuria”)—occasional sign
  • Advanced signs—stiffness; excitement; seizures
  • Increased body temperature (known as “hyperthermia”)
  • Exaggerated reflexes (known as “hyperreflexia”)
  • Muscle rigidity
  • Dilated pupils (known as “mydriasis”)
  • Rapid breathing (known as “tachypnea”)
  • Rapid heart rate (known as “tachycardia”)—heart rate may reach 200 beats per minute or more
  • Irregular heartbeats (known as “arrhythmias”)
  • High blood pressure (known as “hypertension”)
  • Increased thirst (known as “polydipsia”)
  • Death—12–48 hours after ingestion

Causes

  • Usually some form of processed chocolate (used for baking and candies, such as milk chocolate)—contain high concentrations of theobromine and caffeine
  • Dogs—eating cocoa bean hulls used as garden mulch

Risk Factors

  • Dogs—most commonly affected because they consume large amounts of many foods quickly
  • Chocolate—highly palatable or tasty and attractive; often readily available and unprotected in homes and kitchens, especially around the holidays when chocolate products and candies are common
  • Use of cocoa bean hull mulch in the garden

Treatment

Health Care

  • Describe the type of chocolate and amount of exposure to your veterinarian; take your pet to a veterinary hospital as a potential poisoning emergency
  • Fluid therapy—prevent dehydration and promote production of urine; correct electrolyte disturbances caused by vomiting, as necessary
  • Control seizures
  • Detoxification (if not having seizures or seizures are controlled)—your veterinarian may induce vomiting (known as “emesis”), flush the stomach with fluids (known as “gastric lavage”), and administer activated charcoal
  • Control overheating (hyperthermia)
  • Treat rapid heart rate (tachycardia)
  • Allow pet to urinate frequently or catheterize the bladder to remove urine to reduce the possibility of the methylxanthines being reabsorbed into the body from the urine

Activity

  • Avoid stress and excitement as these could make nervous system signs (hyperreflexia or seizures) worse

Diet

  • Suddenly (acutely) affected pet—do not feed
  • Recovering or convalescent pet—bland diet for several days to allow recovery from gastrointestinal problems

Surgery

  • Rarely, a solid mass or hard lump of chocolate could form, which must be removed surgically

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.

  • Induce vomiting (emesis)—only if the pet is not having seizures—apomorphine, syrup of ipecac, or 3% hydrogen peroxide
  • Flush the stomach (gastric lavage)—only before onset of vomiting and other clinical signs or vomiting has been controlled, if drugs to induce vomiting are not effective, seizures are controlled, and an endotracheal tube is in place
  • Once vomiting is controlled—activated charcoal to attract and keep the remaining alkaloids in the gastrointestinal tract
  • Osmotic cathartic—sodium sulfate or sorbitol 70% promotes gastrointestinal elimination of chocolate
  • Hyperactivity and seizures—controlled with diazepam
  • Ventricular rapid heart rate (known as “tachycardia”) in dogs—lidocaine (without epinephrine)
  • Serious abnormal heart rhythms (arrhythmias) that persist after medical treatment—metoprolol or propranolol; metoprolol preferred but may be difficult to obtain; may use oral therapy once the pet is stable; monitor electrocardiogram (ECG) and watch for hypotension (a possible complication to this treatment)
  • In rare cases of slow heart rate (known as “bradycardia”)—atropine
  • Control may be obtained with methocarbamol
  • If response to diazepam inadequate—consider phenobarbital
  • For refractory seizures—pentobarbital; “refractory seizures” are seizures that do not respond or are not controlled with treatment

Follow-Up Care

Patient Monitoring

  • Electrocardiogram (ECG) to evaluate and monitor abnormal heart rhythms or irregular heartbeats (arrhythmias)
  • Watch for mild to moderate kidney disease (known as “nephrosis”) in recovering pets

Preventions and Avoidance

  • Chocolate is among the 20 most common poisonings reported in recent literature, by small animal veterinary practices, animal poison control centers, and human poison control centersKeep chocolate in a secure location, out of reach of pets
  • Do not use cocoa bean hull mulch in areas accessible to pets

Possible Complications

  • Pregnant pet—risk for abnormal development of fetus leading to birth defects of newborns
  • Nursing pets—overstimulation of nervous system in nursing newborns

Expected Course and Prognosis

  • Expected course—12–36 hours, depending on dosage of chocolate and effectiveness of decontamination and treatment
  • Successfully treated pets—usually recover completely
  • Prognosis—good if oral decontamination occurs within 2–4 hours of ingestion; guarded with advanced signs of seizures and irregular heartbeats (arrhythmias)

Key Points

  • Chocolate ingestion is hazardous to pets; if you suspect your pet has eaten chocolate, chocolate-containing products, or cocoa bean hull mulch, contact your veterinarian immediately
  • Describe the type of chocolate and amount of exposure to your veterinarian; take your pet to a veterinary hospital as a potential poisoning emergency
  • Chocolate is among the 20 most common poisonings reported in recent literature by small animal veterinary practices, animal poison control centers, and human poison control centers
  • Keep chocolate in a secure location, out of reach of pets
  • Be especially careful around holidays when chocolate products and candies are readily available
  • Do not use cocoa bean hull mulch in areas accessible to pets

Anticoagulant Rodenticide Poisoning

Anticoagulant Rodenticide Poisoning – An Overview

  • An “anticoagulant” is something that prevents blood from clotting; a “rodenticide” is a product that kills rodents (such as mice and rats)—commonly known as “rat bait”
  • Blood-clotting disorder (known as a “coagulopathy”) caused by reduced vitamin K1–dependent clotting factors in the circulation after exposure to anticoagulant rodenticides
  • “Clotting factors” are components in the blood involved in the clotting process—the clotting factors are identified by Roman numerals I through XIII

Signalment/Description of Pet

Mean Age and Range

  • Younger pets may be more likely to ingest rat bait than older pets

Signs/Observed Changes in Pet

  • Difficulty breathing (known as “dyspnea”) and exercise intolerance
  • Bleeding
  • Localized mass of blood in a tissue or organ (known as a “hematoma”)—often along the lower areas of the body (known as the “ventrum”) and at sites where intravenous catheters were placed or blood was drawn (known as “venipuncture sites”); may have multiple hematomas
  • Muffled heart or lung sounds
  • Pale gums and moist tissues of the body (known as “mucous membranes”)
  • Sluggishness (lethargy)
  • >Depression

Causes

  • Exposure to anticoagulant rodenticide products (rat bait)
  • First-generation coumarin anticoagulants (such as warfarin, pindone)—have been largely replaced by more potent second-generation anticoagulants
  • Second-generation anticoagulants (such as brodifacoum, bromadiolone, diphacinone, and chlorophacinone)—are generally more toxic and some persist longer in the animal’s body than first-generation agents
  • Difenthialone (D-Cease Mouse and Rat Bait Pellets)—highly toxic to mice and rats; less toxic to dogs than are brodifacoum, bromadiolone, chlorophacinone, and warfarin

Risk Factors

  • Use of anticoagulant rodenticides
  • Anticoagulant rodenticide poisoning may be slightly more likely in the spring and fall, when rodenticide products are used
  • Small doses over several days more dangerous than a single large dose; either type of exposure may cause bleeding problems
  • Secondary poisoning by consumption of poisoned rodents—unlikely

Treatment

Health Care

  • Inpatient—sudden (acute) crisis
  • Outpatient—consider once the blood-clotting disorder (coagulopathy) is stabilized
  • Fresh whole blood or plasma transfusion—may be required if pet is bleeding; provides immediate access to vitamin K1–dependent clotting factors; whole blood may be preferred with severely low red blood cell count (known as “severe anemia”) from sudden (acute) or long-term (chronic) blood loss

Activity

  • Confine the pet during the early stages; activity enhances blood loss/li>

Diet

  • No recognized effect

Surgery

  • Procedure to tap the chest (known as “thoracocentesis”)—may be important for removing free blood in the space between the chest wall and lungs (known as the “pleural space”), which causes difficulty breathing (dyspnea) and breathing failure
  • Must correct blood-clotting disorder (coagulopathy) before surgery

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

  • Vitamin K1—administered by mouth, as directed by your pet’s veterinarian; length of treatment depends on the specific anticoagulant rodenticide product to which the pet was exposed; feeding of a small amount of fat, such as canned dog food, helps absorption of vitamin K1

Follow-Up Care

Patient Monitoring

  • Blood tests (activated clotting time [ACT] and prothrombin time [PT]) to evaluate clotting status—assess effectiveness of therapy; monitoring continued 3–5 days after discontinuation of vitamin K1 treatment

Preventions and Avoidance

  • Do not allow pets to have access to anticoagulant rodenticides (rat bait)

Possible Complications

  • Secondary bacterial pneumonia after bleeding into the lungs
  • Bleeding into or around the brain (known as “intracranial hemorrhage”), leading to nervous system signs (such as stupor or coma)
  • Bleeding into the joints (known as “intra-articular hemorrhage”), leading to lameness
  • Death

Expected Course and Prognosis

  • If the pet survives the first 48 hours of sudden (acute) blood-clotting disorder (coagulopathy)—prognosis improves

Key Points

  • Anticoagulant rodenticide (rat bait) poisoning is a common problem—many rodent baits are sold over the counter and widely used in homes
  • Reexposure of the pet to anticoagulant rodenticides could be a serious problem
  • Do not allow pets to have access to anticoagulant rodenticides

Acetaminophen Toxicity

Acetaminophen Toxicity – An Overview

  • Results from owners overdosing the pet with over-the-counter medications containing acetaminophen, a medication intended to control pain or fever in humans

Signalment/Description of Pet

  • Young and small dogs – greater risk from owner-given single-dose acetaminophen medications

Signs/Observed Changes in Pet

  • May develop 1–4 hours after dosing
  • Progressive depression
  • Rapid breathing
  • Darkened mucous membranes (moist tissues of body, such as gums)
  • Drooling (salivation)
  • Vomiting
  • Abdominal pain
  • Rapid breathing (known as “tachypnea”) and bluish discoloration of skin and moist tissues of body (known as “cyanosis”) due to a abnormal compound (methemoglobin) in the blood (condition known as “methemoglobinemia”) that disrupts the ability of the red blood cells to carry oxygen to the body
  • Fluid buildup (edema)—face, paws, and possibly forelimbs; after several hours
  • Chocolate-colored urine due to the presence of blood in the urine (known as “hematuria”) and the presence of methemoglobin in the urine (known as “methemoglobinuria”);
  • Death

Causes

  • Acetaminophen overdosing

Risk Factors

  • Nutritional deficiencies of glucose and/or sulfate
  • Simultaneous administration of other glutathione-depressing drugs

Treatment

Health Care

  • With methemoglobinemia (abnormal compound [methemoglobin] in the blood that disrupts the ability of the red blood cells to carry oxygen to the body)—must evaluate promptly; inpatient care
  • With dark or bloody urine or yellowish discoloration of skin and moist tissues of the body (known as “jaundice” or “icterus”)—inpatient care
  • Gentle handling—imperative for clinically affected pets
  • The veterinarian will induce vomiting (known as “emesis”) and may perform flushing of the stomach (known as “gastric lavage”)—useful within 4–6 hours of ingestion of acetaminophen
  • Low red blood cell count (known as “anemia”), blood in the urine (hematuria), or presence of hemoglobin in the urine (known as “hemoglobinuria”)—may require whole blood transfusion
  • Fluid therapy to maintain hydration and electrolyte balance
  • Drinking water should be available at all times

Activity

  • Restricted

Diet

  • Food—offered 24 hours after initiation of treatment

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

  • Activated charcoal—administered immediately after the veterinarian has induced vomiting or flushed the stomach (gastric lavage) and after vomiting is controlled; activated charcoal is used to attract and keep the remaining acetaminophen in the gastrointestinal tract
  • N-acetylcysteine (Mucomyst®) is administered; considered to be an antidote for acetaminophen toxicity
  • Other sulfur donor drugs—if N-acetylcysteine not available; sodium sulfate
  • 1% methylene blue solution—combats methemoglobinemia without inducing red blood cell destruction (known as a “hemolytic crisis”)
  • Ascorbic acid—slowly reduces methemoglobinemia

Follow-Up Care

Patient Monitoring

  • Continual clinical monitoring of methemoglobinemia (abnormal compound [methemoglobin] in the blood that disrupts the ability of the red blood cells to carry oxygen to the body)
  • Serum liver enzyme activities to monitor liver damage
  • Blood glutathione level—provide evidence of the effectiveness of therapy

Preventions and Avoidance

  • Give careful attention to acetaminophen dose; acetaminophen should only be given to dogs under a veterinarian’s supervision

Possible Complications

  • Liver damage and resulting scarring (fibrosis)—may compromise long-term liver function in recovered pets

Expected Course and Prognosis

  • Rapidly progressive methemoglobinemia (abnormal compound [methemoglobin] in the blood that disrupts the ability of the red blood cells to carry oxygen to the body)—serious sign
  • Methemoglobin concentrations greater than 50%—grave prognosis
  • Progressively rising serum liver enzymes 12–24 hours after ingestion—serious concern
  • Expect clinical signs to persist 12–48 hours; death owing to methemoglobinemia possible at any time
  • Receiving prompt treatment that reverses methemoglobinemia and prevents excessive liver damage may recover fully
  • Death as a result of liver damage may occur in a few days

Key Points

  • Acetaminophen should only be given to dogs under a veterinarian’s supervision
  • Considerably less frequent in dogs
  • Treatment in clinically affected pets may be prolonged and expensive
  • Pets with liver injury may require prolonged and costly management

False Pregnancy

False Pregnancy – An Overview

  • Display of maternal behavior and physical signs of pregnancy 2–3 months after “heat” or “estrus” by a non-pregnant bitch
  • Physical, hormonal, and behavioral changes following an unsuccessful mating or spontaneous ovulation in the queen; “ovulation” is the release of the egg from the ovary
  • A female dog is a “bitch”
  • False pregnancy also known as “pseudopregnancy,” “phantom pregnancy,” or “pseudocyesis”

Signalment/Description of Pet

Breed Predilections

  • None

Mean Age and Range

  • Any age

Predominant Sex

  • Female
  • Non-pregnant bitches that were in heat or estrus 2–3 months earlier and that are experiencing a decline in serum progesterone concentration; “progesterone” is the female hormone that supports and maintains pregnancy in a pregnant pet—it normally remains high in non-pregnant bitches for several weeks following their heat or estrous cycles

Signs/Observed Changes in Pet

  • Severity variable among individuals and from one occurrence to the next within the same individual
  • Behavior changes—nesting, mothering activity (such as mothering a stuffed toy or unrelated puppies), restlessness, and self-nursing
  • Aggression
  • Sluggishness (lethargy)
  • Abdominal distention (rare) and breast or mammary gland enlargement
  • Weight gain
  • Vomiting, depression, and lack of appetite (known as “anorexia”)
  • Large mammary glands that secrete a clear to milky to brownish fluid

Causes

  • False pregnancy is a normal phenomenon in bitches following ovulation (release of the egg from the ovary)
  • Progesterone and prolactin—drop in progesterone concentration causes prolactin concentration to rise; “progesterone” is the female hormone that supports and maintains pregnancy in a pregnant pet—it normally remains high in non-pregnant bitches for several weeks following heat or estrus; “prolactin” is a hormone that stimulates breast or mammary gland enlargement and milk production (known as “lactation”)
  • Treatment with progestin (substance capable of producing the effects of the female hormone, progesterone) for conditions not related to false pregnancy—may develop signs of false pregnancy after drug withdrawal
  • Surgical removal of the ovaries (known as “oophorectomy” or “ovariectomy”) or the ovaries and uterus (known as “ovariohysterectomy” or “spay”) during the period when progesterone levels are high following heat or estrus—may develop signs of false pregnancy 3–4 days following surgery due to the sudden drop in progesterone
  • Inadequate levels of thyroid hormone (known as “hypothyroidism”) with high thyroid-stimulating hormone (TSH) concentration in the blood, which stimulates prolactin secretion—may note some associated clinical signs

Risk Factors

  • Ovariectomy or ovariohysterectomy or spay performed during the period when progesterone levels are high following heat or estrus
  • Treatment with progestins
  • Not thought to be influenced by previous pregnancy
  • Does not cause susceptibility to other reproductive diseases

Treatment

Health Care

  • Usually no treatment needed—all pregnant, non-pregnant, and false-pregnant ovulating dogs go through a similar stage of high progesterone levels following heat or estrus
  • Outpatient for medical treatment
  • Inpatient—planned surgery
  • Progestins (substances capable of producing the effects of the female hormone, progesterone) and androgens (male hormones) to decrease secretion of prolactin; “prolactin” is a hormone that stimulates breast or mammary gland enlargement and milk production (lactation)
  • Surgical removal of the ovaries and uterus (ovariohysterectomy or spay) during anestrus (the time between heat or estrous cycles)—prevents recurrence
  • Mammary glands—minimize stimuli that promote milk production (lactation); use cold packs applied to the breasts or mammary glands
  • Elizabethan collar—prevent self-nursing or licking; but even rubbing of the collar on the mammary glands may be sufficient to prolong milk production (lactation)

Diet

  • Reduction of food for several days may reduce milk production (lactation)

Surgery

  • Surgical removal of the ovaries and uterus (ovariohysterectomy or spay)—if the bitch or queen is not intended for breeding; recommended during the next anestrus (the time between heat or estrous cycles), when possible

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.

  • Cabergoline (Dostinex)—a prolactin inhibitor; “prolactin” is a hormone that stimulates breast or mammary gland enlargement and milk production (lactation)
  • Bromocriptine (Parlodel)—not approved for veterinary use in the United States and Canada; will reduce milk production (lactation) by 89% and decrease behavioral signs of false pregnancy by 90%
  • Diazepam—medication used to decrease anxiety; short-term treatment for bitches with extreme behavioral signs
  • Mibolerone—to reduce signs of false pregnancy in bitches; should not be used in queens

Follow-Up Care

Patient Monitoring

  • Surgical removal of the ovaries (ovariectomy) or ovaries and uterus (ovariohysterectomy or spay) during anestrus (the time between heat or estrous cycles)—prevents recurrence
  • “Heat” or estrus suppression

Expected Course and Prognosis

  • Usually resolves in 2–4 weeks without treatment
  • Treatment with bromocriptine, cabergoline, or mibolerone—may resolve condition in 5–7 days
  • False pregnancy may develop during subsequent heat or estrous cycles
  • False pregnancy does not impact future fertility

Key Points

  • False pregnancy is a normal phenomenon in bitches following ovulation (release of the egg from the ovary)
  • False pregnancies do not impact future fertility
  • Bitches should be evaluated for actual pregnancy before treating for false pregnancy
  • No association has been identified between false pregnancy and reproductive abnormalities
  • Pyometra (inflammation with accumulation of pus in the uterus) can develop in queens following spontaneous ovulation (release of the egg from the ovary)

Pyometra

Pyometra – An Overview

  • Cystic endometrial hyperplasia—hormonally mediated, progressive, abnormal thickening in the lining of the uterus (known as the “endometrium”), characterized by the presence of fluid-filled sacs or cysts
  • Pyometra—develops secondary to cystic endometrial hyperplasia or inflammation of the lining of the uterus (known as “endometritis”); develops when bacteria invade the abnormally thickened lining of the uterus (lining of the uterus known as the “endometrium”) and pus accumulates in the uterus
  • The female dog is a “bitch”

Signalment/Description of Pet

Mean Age and Range

  • Usually greater than 6 years of age
  • Young pets—especially if treated with female hormones (estrogen) or progestogen (any substance capable of producing the effects of the female hormone, progesterone)
  • Usually diagnosed 1–12 weeks after “heat” or “estrus”
  • Accumulation of pus in the uterine stump (known as “pyometra of the uterine stump”) in spayed pets—may develop any time after surgical removal of the ovaries and uterus (known as a “spay” or “ovariohysterectomy”)

Predominant Sex

  • Female only

Signs/Observed Changes in Pet

  • Closed cervix (the “cervix” is the lower part of the uterus that extends into the vagina [the tubular passageway or birth canal, leading from the opening of the vulva to the cervix]; a “closed cervix” is one in which the muscles surrounding the cervix are contracted and the opening into the uterus is “shut” so no pus or discharge can drain from the uterus—signs of generalized (systemic) illness, progressing to signs of generalized disease caused by the spread of bacteria in the blood (known as “septicemia” or “blood poisoning”) and shock
  • Uterus—enlarged with closed cervix (where the pus or discharge cannot drain from the uterus); may not be enlarged with open cervix (where the muscles surrounding the cervix are relaxed, allowing the opening into the uterus to expand and pus or discharge to drain from the uterus, through the vagina and vulva [external genitalia])
  • Discharge from the vulva (external genitalia)—depends if cervix is open or closed; discharge may be bloody or may contain mucus and pus
  • Depression and sluggishness (lethargy)
  • Lack of appetite (known as “anorexia”)
  • Increased urination (known as “polyuria”) and increased thirst (known as “polydipsia”)
  • Vomiting
  • Abdominal distension

Causes

  • repeated exposure of the lining of the uterus (endometrium) to estrogen followed by exposure to progesterone with each “heat” or “estrus” (whether or not the bitch becomes pregnant); this hormonal pattern is unique to the bitch

Treatment

Health Care

  • Inpatient
  • Accumulation of pus in the uterus (pyometra)—life-threatening condition if the cervix is closed (where pus or discharge cannot drain from the uterus)
  • Supportive care—immediate intravenous fluid administration and antibiotics

Surgery

  • Accumulation of pus in the uterus (pyometra), open and closed cervix—surgical removal of the ovaries and uterus (spay or ovariohysterectomy) preferred treatment; long-term (chronic) progressive disease
  • Accumulation of pus in the uterus (pyometra), with a closed cervix (where pus or discharge cannot drain from the uterus)—caution should be used during surgical removal of the ovaries and uterus (spay or ovariohysterectomy); the enlarged uterus may be very fragile
  • Uterine rupture or leakage of pus from the uterine stump—repeated flushing (lavage) of the abdominal cavity with sterile saline

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.

Antibiotics

  • Initial antibiotic selected by your pet’s veterinarian based on experience, pending results of bacterial culture and sensitivity test
  • Should be administered to all pets with inflammation characterized by accumulation of pus in the uterus (pyometra)
  • Common choices—ampicillin; enrofloxacin (Baytril®)
  • Antibiotics—not effective as the sole treatment, unless the uterus is of normal size and the serum progesterone level is less than 2 ng/ml on blood tests

Prostaglandins

Prostaglandin F2a (PGF2a)

  • Prostaglandins cause smooth muscle contractions and subsequent emptying of the uterus and decrease in serum progesterone concentration, based on dosage
  • For 2–7 days, until the uterus nears normal size as determined by feeling the abdomen, x-rays, or ultrasound examination or until no fluid is visible within the uterus as seen by ultrasound examination
  • Reevaluate the pet 2–4 weeks after discontinuation of prostaglandins; if the uterus has increased in size or the pet still has marked discharge from the vulva (external genitalia), medical treatment protocol can be repeated
  • Surgical removal of the ovaries and uterus (spay or ovariohysterectomy)—performed in pets that do not respond to treatment with prostaglandin (lack of response indicated by continued enlargement of the uterus or presence of fluid in the uterus, or discharge from the vulva is still present after two courses of medical treatment)

Closprostenol

  • Injection under the skin (subcutaneous or SC injection) daily for 7–14 days

Miscellaneous

  • Aglepristone—effectiveness improved with prostaglandin treatment at the same time; not readily available in the United States
  • Cabergoline—for 7–14 days with prostaglandin treatment
  • Drugs that enhance the immune response (such as estrogens) or certain agents (such as oxytocin and ergot), which induce contraction of the muscles of the uterus are unreliable; “oxytocin” is a female hormone that causes uterine contractions and promotes milk release during lactation

Follow-Up Care

Patient Monitoring

  • Release from the hospital when the uterus is of near normal size or when no fluid is visible within the uterus by ultrasound examination, and clinical signs have lessened in severity or disappeared; reevaluate in 2–4 weeks
  • Antibiotics—administration should be continued for 3–4 weeks
  • Discharge from the vulva (external genitalia)—may persist for up to 4 weeks
  • Serial complete blood counts (CBCs)—the white blood cell (WBC) count rises rapidly after surgical removal of the ovaries and uterus (spay or ovariohysterectomy), because the bone marrow continues to release neutrophils (a type of white blood cell) into the bloodstream, from which they can no longer enter the uterus

Preventions and Avoidance

  • Next proestrus (time from beginning of vaginal bleeding of “heat” until the bitch allows male to mount and breed)—obtain a specimen of the anterior vagina for bacterial culture, using a guarded culture swab
  • Treat bitch with an appropriate antibiotic for 3 weeks
  • Breed during the “heat” or “estrus” immediately following medical treatment—the pregnant uterus may be less susceptible to reinfection; bitch with underlying cystic endometrial hyperplasia has limited breeding life (best to get desired number of puppies as soon as possible); bitch not more likely to clear the disease spontaneously if allowed to cycle without being bred

Possible Complications

  • Bitch may enter “heat” or “estrus” sooner after medical treatment than anticipated
  • Accumulation of pus in the uterus (pyometra)—life-threatening condition if the cervix is closed (where pus or discharge cannot drain from the uterus)

Expected Course and Prognosis

  • Underlying cystic endometrial hyperplasia (thickening of the uterine lining with the presence of fluid-filled sacs or cysts) still exists; predisposed to recurrence
  • Breed bitch to desired stud dogs in a timely manner; use of subfertile stud dogs is not recommended
  • Recommend surgical removal of ovaries and uterus (spay or ovariohysterectomy) as soon as breeding life is over
  • Closed-cervix (where pus or discharge cannot drain from the uterus) inflammation of the uterus with accumulation of pus (pyometra) can be associated with uterine rupture and inflammation of the lining of the abdomen (known as “peritonitis”)

Key Points

  • Surgical removal of ovaries and uterus (spay or ovariohysterectomy) is the preferred treatment
  • Medical treatment should be considered only for a valuable breeding animal that has an open cervix (where pus or discharge can drain from the uterus) and does not have excess levels of urea and other nitrogenous waste products in the blood (known as “uremia” or “azotemia”); except when breeding is planned, non-progestational, estrus-suppressing drugs must be given for life
  • Medical treatment of closed-cervix (where pus or discharge cannot drain from the uterus) inflammation of the uterus with accumulation of pus (pyometra) can be associated with uterine rupture and inflammation of the lining of the abdomen (peritonitis)
  • Medical treatment probably does not cure underlying cystic endometrial hyperplasia (thickening of the uterine lining with the presence of fluid-filled sacs or cysts) in pets with either open- or closed-cervix pyometra, but may enable some affected bitches to reproduce

Tracheal Collapse

Tracheal Collapse (Abnormality of the Windpipe)- An Overview

  • “Upper respiratory tract” (also known as the “upper airways”) includes the nose, nasal passages, throat (pharynx), and windpipe (trachea)
  • “Lower respiratory tract” (also known as the “lower airways”) includes the bronchi, bronchioles, and alveoli (the terminal portion of the airways, in which oxygen and carbon dioxide are exchanged)
  • The windpipe or trachea is the large airway that carries air from the nose and throat to the airways (bronchi) that go to the lungs
  • “Tracheal collapse” is a reduction in the diameter of the lumen of the windpipe (trachea) during breathing; it is considered to be a “dynamic” process as the lumen’s diameter changes with the movements of breathing (inspiration and expiration)
  • May involve the windpipe (trachea) in the neck (known as the “cervical trachea”), the windpipe (trachea) within the chest (known as the “intrathoracic trachea”), or both segments
  • “Broncho-” refers to the bronchus (plural, bronchi); “malacia” refers to weakening or softening of an organ or tissue; “bronchomalacia” refers to a condition in which the bronchi and smaller airways collapse due to weakening of the walls of the bronchi—bronchomalacia may be present by itself or may be present at the same time as collapse of the windpipe or trachea (tracheal collapse)
  • Compression of the windpipe (trachea) or bronchi as a result of enlarged lymph nodes or the presence of tumors are not considered part of this condition

Genetics

  • Unknown

Signalment/Description of Pet

Breed Predilections

  • Miniature poodles, Yorkshire terriers, Chihuahuas, Pomeranians, and other small- and toy-breed dogs

Mean Age and Range

  • Middle-aged to elderly—onset of signs at 4–14 years of age
  • Severely affected pets may be less than 1 year of age

Signs/Observed Changes in Pet

  • Usually worsened by excitement, heat, humidity, exercise, or obesity
  • Dry, honking cough
  • May have long-term (chronic) intermittent coughing or difficulty breathing
  • Retching (attempting to vomit)—often seen due to attempts to clear respiratory secretions from the voice box (larynx)
  • Rapid breathing (known as “tachypnea”), exercise intolerance, and/or severe breathing difficulty (known as “respiratory distress”)—common
  • Breathing difficulty (respiratory distress)—seen during inspiration (breathing in) with collapse of the windpipe in the neck (cervical tracheal collapse); seen during expiration (breathing out) with collapse of the windpipe within the chest (intrathoracic tracheal collapse)
  • Bluish discoloration of the skin and moist tissues (mucous membranes) of the body caused by inadequate oxygen levels in the red blood cells (known as “cyanosis”) or fainting (known as “syncope”)—may see in severely affected individuals
  • Increased tracheal sensitivity
  • Whistling sounds (wheezing) or musical sounds over the narrowed area of the windpipe may be heard while listening with a stethoscope (known as “auscultation”)
  • A “snap” sound may be heard (when listening with a stethoscope) at the end of expiration, when large segments of the windpipe (trachea) collapses within the chest (intrathoracic tracheal collapse) during forceful expiration
  • Abnormal breath sounds on listening to the lungs with a stethoscope (auscultation)—increased intensity or breath sounds over the bronchi; short, rough snapping sounds (known as “crackles”); and squeaking or whistling sounds (known as “wheezes”)—indicate coexistent small airway disease
  • Heart murmurs (mitral valve insufficiency murmurs)—often are found in small-breed dogs with tracheal collapse
  • Normal to low heart rate
  • Loud second heart sound detected when listening to the heart with a stethoscope (auscultation)—suggests increased blood pressure within the lungs (known as “pulmonary hypertension”)
  • Enlarged liver (known as “hepatomegaly”)—cause unknown

Causes

  • Unknown cause
  • Defects in the development of cartilage in the windpipe (trachea) or nutritional factors are suspected
  • Long-term (chronic) small-airway disease suggested to contribute to development of weakening of the bronchi (bronchomalacia), but relationship is not clear

Risk Factors

  • Obesity
  • Infection or inflammation of the airways
  • Upper airway blockage or obstruction
  • Intubation with an endotracheal tube (passage of an endotracheal tube through the mouth and into the windpipe [trachea] to allow oxygen to reach the lungs)

Treatment

Health Care

  • Outpatient—stable pets
  • Inpatient—oxygen therapy and sedation for severe breathing difficulty (respiratory distress) or for severely anxious pets

Activity

  • Severely limited, until the pet is stable
  • During management of disease—gentle exercise recommended to encourage weight loss

Diet

  • Most affected dogs improve after losing weight
  • Institute weight-loss program with a high-fiber reducing diet
  • Feed 80% of total daily requirement of calories; use a slow weight-loss program

Surgery

  • Surgery—may benefit some pets, primarily those with collapse of the windpipe (trachea) in the neck (cervical tracheal collapse)
  • Treatment of upper airway obstructive disorders (such as elongated soft palate or turning inside-out of a portion of the voice box or larynx [known as “everted laryngeal saccules”])—may reduce tracheal signsPlacement of stents to keep the lumen of the windpipe open, in selected pets (primarily with collapse of the windpipe [trachea] in the neck [cervical tracheal collapse]) by a skilled surgeon—will enhance quality of life and reduce clinical signs when adequate stabilization of the airway can be achieved and when weakening of the bronchi (bronchomalacia) does not limit resolution of disease
  • A “stent” is a medical tube used to hold open an airway; stents can be life-saving in certain cases with airway collapse within the chest

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.

  • Sedation and cough suppression—butorphanol; addition of a tranquilizer (acepromazine) may enhance sedative effects and further reduce the cough reflex; narcotic cough suppressants (butorphanol or hydrocodone) effective for long-term (chronic) treatment
  • Drugs to dilate the bronchi and bronchioles (known as “bronchodilators”); dilation of small airways and lowering pressure gradients with lower airway disease—sustained-release theophylline or terbutaline; bronchodilators have no effect on the diameter of the windpipe (trachea)
  • Bacterial infection is uncommon; however, doxycycline is an antibiotic that is sometimes beneficial by decreasing the number of bacteria in the airway or by reducing inflammation
  • Reduction of inflammation of the windpipe (trachea)—prednisone; consider inhaled steroids given via face mask and spacer chamber
  • Robitussin DM—may provide relief to pet, reduce the severity of the cough, but is not a cure (known as “palliation”); use any medications only under the direction of your pet’s veterinarian

Follow-Up Care

Patient Monitoring

  • Body weight
  • Exercise tolerance
  • Pattern of breathing
  • Incidence of cough

Preventions and Avoidance

  • Avoid obesity in breeds commonly afflicted with tracheal collapse
  • Avoid heat and humidity
  • Use a harness rather than a collar (a collar puts pressure on the windpipe, and may aggravate the problem)

Possible Complications

  • Severe breathing difficulties that do not respond to medical treatment (known as “intractable respiratory distress”) leading to respiratory failure or euthanasia
  • Consider likelihood of complications after surgery (such as persistent cough, severe breathing difficultly [respiratory distress], or paralysis of the voice box (larynx; laryngeal paralysis]);
  • Some pets may require a permanent surgical opening into the windpipe or trachea (known as a “permanent tracheostomy”)

Expected Course and Prognosis

  • Combinations of medications, along with weight control, may reduce clinical signs; however, pet likely will cough throughout life and can have periods when clinical signs worsen
  • Surgery—may benefit some dogs, primarily those with collapse of the windpipe (trachea) in the neck (cervical tracheal collapse)
  • Stent placement—benefits some dogs, primarily those with windpipe (trachea) collapse within the chest
  • Prognosis—based on evidence and degree of airway blockage

Key Points

  • “Tracheal collapse” is a reduction in the diameter of the lumen of the windpipe (trachea) during breathing; it is considered to be a “dynamic” process as the lumen’s diameter changes with the movements of breathing (inspiration and expiration)
  • Obesity, overexcitement, and humid conditions may precipitate a breathing crisis
  • Use a harness instead of a collar
  • Combinations of medications, along with weight control, may reduce clinical signs
  • Tracheal collapse is irreversible; treatment is designed to decrease triggers of cough
  • Complications may occur following surgery; complications include persistent cough, breathing distress, or paralysis of the voice box or larynx (laryngeal paralysis)
  • Some pets may require a permanent surgical opening into the windpipe or trachea (permanent tracheostomy)
  • Extensive follow-up is required for pets that have stents placed in the airways, to monitor for damage to the stent and for migration of the stent

Infectious Canine Tracheobronchitis/Kennel Cough

Infectious Canine Tracheobronchitis/Kennel Cough – An Overview

  • Any contagious respiratory disease of dogs that is manifested by coughing

Signalment/Description of Pet

Breed Predilections

  • None

Mean Age and Range

  • Most severe in puppies 6 weeks–6 months old
  • May develop in dogs of all ages and often with preexisting subclinical airway disease (such as abnormal development of the respiratory tract or long-term inflammation of the bronchi [known as “chronic bronchitis”])

Signs/Observed Changes in Pet

  • Related to the degree of respiratory tract damage and age of the affected dog
  • May be nonexistent, mild, or severe with pneumonia
  • Most viral, bacterial, and Mycoplasma agents spread rapidly from seemingly healthy dogs to other dogs in the same environment; signs usually begin about 4 days after exposure to the infecting agent(s)
  • Uncomplicated—cough in an otherwise healthy dog is characteristic; may be dry and hacking, soft and dry, moist and hacking, or sudden and sharp, followed by gagging or spitting up of mucus; excitement, exercise, changes in temperature or humidity of the inspired air, and gentle pressure (such as from collar) on the windpipe (trachea) induce a sudden onset of coughing
  • Uncomplicated—cough readily induced with pressure on the windpipe (trachea) during physical examination; lung sounds often normal; otherwise appears healthy
  • Severe—decreased appetite (known as “inappetence”) to loss of appetite (known as “anorexia”); cough (when noted) is moist and productive; may see sluggishness (lethargy), difficulty breathing (known as “dyspnea”), and exercise intolerance
  • Severe—may have constant, low-grade, or fluctuating fever (39.4–40.0°C; 103–104°F); may have increased intensity of normal lung sounds; short, rough lung sounds (known as “crackles”) heard with a stethoscope; or (less frequently) whistling or squeaking sounds (known as “wheezes”)

Causes

  • Viral—canine distemper virus; canine adenovirus-2; canine parainfluenza virus; canine adenovirus-1; canine respiratory coronavirus; canine reovirus type 1, 2, or 3; canine herpesvirus-1; canine influenza virus
  • Canine adenovirus-2 and canine parainfluenza virus may damage the lining cells of the respiratory tract to such an extent that invasion by various bacteria and Mycoplasma cause severe airway disease
  • Bacterial—Bordetella bronchiseptica, (with no other respiratory disease-causing agents) produces clinical signs indistinguishable from those of other bacterial causes; Pseudomonas, Escherichia coli, Klebsiella, Pasteurella, Streptococcus, Mycoplasma, and other species equally likely

Risk Factors

  • Dogs housed with multiple other dogs, such as pet shops, humane society shelters, research facilities, and boarding and training kennels
  • Housing with less than ideal hygienic conditions; overcrowding conditions
  • Preexisting subclinical airway disease, such as abnormal development of the respiratory tract or long-term inflammation of the bronchi (chronic bronchitis)

Treatment

Health Care

  • Outpatient—strongly recommended for uncomplicated disease
  • Inpatient—strongly recommended for complicated disease and/or pneumonia
  • Fluid administration—indicated for complicated disease and/or pneumonia

Activity

  • Enforce rest—for at least 14–21 days with uncomplicated disease; for at least the duration of x-ray evidence of pneumonia in severely affected dogs

Diet

  • Good-quality canned or dry commercial food

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.

  • Antibiotic therapy—amoxicillin/clavulanic acid or doxycycline—initial treatment of uncomplicated disease
  • Antibiotic therapy—cephalosporin (such as cefazolin) with gentamicin or amikacin or enrofloxacin—usually effective for severe pneumonia; continue antibiotic therapy for at least 10 days beyond resolution of pneumonia as seen on x-rays (radiographs)
  • Bordetella. bronchiseptica or other resistant bacteria—some antibiotics may not reach adequate levels in the lower respiratory tract to be effective, so administration of these antibiotics by mouth or injection may have limited effectiveness; treating with a fine medicated spray (known as “nebulization”) containing kanamycin, gentamicin, or polymyxin B maybe effective, when administered daily for 3–5 days; also administer systemic antibiotics in dogs with lung disease
  • Cough suppressants (such as butorphanol or hydrocodone)—effective in decreasing the dry, nonproductive cough, not associated with bacterial infectionDrugs to increase the openings in the bronchi and bronchioles (known as “bronchodilators,” such as extended-release theophylline)—may be used to control narrowing of the bronchi and bronchioles due to contraction of smooth muscles in the walls of these airways (known as “bronchospasm”); bronchospasm is detected clinically by whistling or squeaking sounds (wheezes)

Follow-Up Care

Patient Monitoring

  • Uncomplicated disease—should respond to treatment in 10–14 days; if the pet continues to cough 14 days or more after adequate treatment, dog should be evaluated again by your pet’s veterinarian
  • Severe disease—repeat chest x-rays (radiographs) until at least 14 days beyond resolution of all clinical signs

Preventions and Avoidance

  • Shedding of the causative virus and/or bacteria of infectious canine tracheobronchitis (kennel cough) in respiratory secretions of dogs undoubtedly accounts for the persistence of this problem in kennels, animal shelters, boarding facilities, and veterinary hospitals; thorough cleaning and disinfecting of kennels is necessary to control spread of disease-causing organisms
  • Do not use cocoa bean hull mulch in areas accessible to pets

Viral and Bacterial Vaccines

  • Available to control disease caused by the principal infectious agents involved
  • Bordetella bronchiseptica and canine parainfluenza virus vaccine—may vaccinate puppies using a vaccine applied into the nose (intranasal vaccine) as early as 2–4 weeks of age, without interference from maternal antibody; follow-up vaccinations should be administered as directed by your pet’s veterinarian; may vaccinate mature dogs with a one-dose intranasal vaccination (at the same time as their puppies or when they receive other vaccinations, as directed by your pet’s veterinarian)
  • Inactivated injectable Bordetella bronchiseptica vaccine—administered as two doses, 2–4 weeks apart; initial vaccination of puppies is recommended at or about 6–8 weeks of age; administer second vaccine at 4 months of age
  • Inactivated canine influenza virus vaccine is available

Expected Course and Prognosis

  • Natural course of uncomplicated disease, if untreated—10–14 days; simple restriction of exercise and prevention of excitement shortens the course
  • Typical course of severe disease—2–6 weeks; may be fatal in pets that develop severe pneumonia, affecting multiple lung lobes

Key Points

  • Isolate the dog from other pets; infected dogs can transmit the disease-causing virus and/or bacteria before onset of clinical signs and afterward until immunity develops
  • Dogs with uncomplicated disease should respond to treatment in 10–14 days
  • Once infection spreads in a kennel, it can be controlled by removing all dogs from the premises for 1–2 weeks and disinfecting with commonly used chemicals, such as sodium hypochlorite (bleach; 1:30 dilution), chlorhexidine, or benzalkonium (NOTE: never mix disinfectants; follow directions for use carefully)

Brachycephalic Airway Syndrome

Brachycephalic Airway Syndrome – An Overview

Upper Airway Problems Seen in Short-Nosed Breeds

  • Partial upper airway obstruction in short-nosed, flat-faced (brachycephalic) breeds of dogs caused by any combination of the following conditions: narrowed nostrils (known as “stenotic nares”); overly long soft palate; turning inside-out of a portion of the voice box or larynx (known as “everted laryngeal saccules”), such that the space for air to pass through the larynx is decreased; and collapse of the voice box or larynx (known as “laryngeal collapse”)
  • An abnormally small windpipe or trachea (known as “hypoplastic trachea”) often is present as well, and can worsen breathing difficulty (respiratory distress)
  • “Upper respiratory tract” (also known as the “upper airways”) includes the nose, nasal passages, throat (pharynx), and windpipe (trachea)

Genetics

  • No specific genes have been identified
  • Short-nosed, flat-faced, broad (brachycephalic) head shape was initially an inherited defect in development of skull bones; has been perpetuated by selective breeding in certain breeds of dogs

Signalment/Description of Pet

Breed Predilections

  • Common syndrome in brachycephalic breeds of dogs

Mean Age and Range

  • Young adults, most diagnosed by 2–3 years of age
  • If diagnosed later than 4 years of age, another disease or condition may be adding to upper airway obstruction leading to diagnosis; older dogs may have a worse outcome post-operatively, but most have some improvement
  • Collapse of the voice box or larynx (known as “laryngeal collapse”) reported in short-nosed, flat faced (brachycephalic) breed puppies as young as 6–7 months of age

Signs/Observed Changes in Pet

  • Snoring; high-pitched, noisy breathing (stridor); noisy breathing when inhaling (stertorous breathing)
  • Rapid breathing (known as “tachypnea”), frequent panting
  • Coughing and gagging
  • Difficulty eating and swallowing
  • Excessive salivation (known as “ptyalism”), regurgitation (return of food or other contents from the esophagus or stomach back up through the mouth), and vomiting
  • Occasionally, fainting (syncope) and episodes of collapse
  • Narrowed nostrils (stenotic nares)
  • Increased breathing (respiratory) effort—may see pulling back of the lips with each breath, open-mouth breathing or constant panting, increased breathing rate, turning of the elbows away from the body (abduction of forelimbs) in an effort to open up the chest, increased abdominal effort during breathing
  • In severe breathing distress, may have increased difficulty in breathing while lying flat (known as “orthopnea”), even to point of reluctance to lie down; and bluish discoloration of skin and moist tissues of body (known as “cyanosis”)
  • Increased body temperature (known as “hyperthermia”) may be present

Causes

  • Brachycephalic airway syndrome results from inherited defects or developmental/growth defects of the upper airway. These defects include the following:
  • Elongated soft palate—reported in over 90% of surgical cases in dogs
  • Narrowed nostrils (stenotic nares)—reported in about 50% of cases in dogs
  • Voice box or laryngeal disease—everted laryngeal saccules (over 50% of affected dogs) and/or laryngeal collapse (approximately 10% of affected dogs)
  • Abnormally small windpipe (hypoplastic trachea); primarily in the English bulldog

Risk Factors

  • Brachycephalic breed
  • Obesity—worsens airway obstruction; associated with poorer outcome following surgical correction; may contribute to backward or reverse flow of stomach contents into the esophagus (known as “gastroesophageal reflux”) and development of aspiration pneumonia
  • Excitement and/or warm, humid weather—increased panting can lead to fluid buildup (edema) in the tissues of the airway, further narrowing the airway opening, and leading to increased body temperature (hyperthermia)
  • Exercise—dogs often are unable to exercise because of airway compromise and low levels of oxygen in their blood (hypoxia)
  • Sedation may cause relaxation of the muscles of throat (pharynx) and soft palate, and may cause complete airway obstruction
  • Lung disease (such as pneumonia, pulmonary edema)—will cause additional breathing compromise
  • Endocrine disease (such as low levels of thyroid [known as “hypothyroidism”] or high levels of steroids [known as “hyperadrenocorticism” or “Cushing’s syndrome”])—could worsen weight gain and cause excessive panting

Treatment

Health Care

  • Surgery recommended for pets with significant clinical signs
  • Emergency presentation with pet in severe breathing distress requires rapid medical intervention, including oxygen supplementation
  • If the pet has high body temperature (hyperthermia), cool with iced water and by directing a fan to blow over the pet (increase convective heat loss); intravenous (IV) fluids should be administered, up to a shock rate if has an extremely elevated body temperature (greater than 106°F)
  • If the airway is completely obstructed, the airway must be opened; this may be accomplished by passing an endotracheal tube through the mouth and into the windpipe (known as “orotracheal intubation”) and/or by a surgical incision into the windpipe (known as a “temporary tracheostomy”)
  • Dexamethasone can be administered to reduce inflammation
  • Pets need 24-hour monitoring because of risk of acute airway obstruction and death
  • Breathing rate and effort, heart rate, pulse quality, color of gums and moist tissues (mucous membrane color), time for pink color to return to gums after blanching them with one’s finger (capillary refill time), temperature, and other physical parameters should be monitored
  • Pulse oximetry and arterial blood gases to determine oxygen levels in the blood may be monitored, depending on severity of condition
  • Intravenous fluids are administered at maintenance rate and handling and stress are minimized

Activity

  • Usually self-limited by the pet

Diet

  • Weight loss is recommended for all overweight dogs
  • For obese, stable pets, weight loss is recommended prior to surgery

SURGERY

  • Evaluation for elongated soft palate generally is performed under general anesthesia when the pet is stable
  • Surgical incision into the windpipe (temporary tracheostomy) can be performed to facilitate exposure or to treat airway obstruction
  • Narrowed nostrils (stenotic nares) are corrected by surgically removing a wedge of the nasal tissue and closing the incision in such a manner to allow the nostril to be enlarged
  • Elongated soft palate is treated by surgically removing a section of the soft palate using surgical scissors, carbon dioxide laser, or a bipolar sealing device
  • Everted laryngeal saccules are treated by surgically trimming the tissue
  • Permanent surgical opening into the windpipe or trachea (known as a “permanent tracheotomy”) may be necessary if severe laryngeal collapse is present

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.

  • Dexamethasone to reduce fluid buildup (edema) and inflammation
  • Broad-spectrum antibiotics are indicated if aspiration pneumonia is present, until culture and sensitivity results are obtained
  • Omeprazole, cisapride, and magnesium hydroxide after meals or sucralfate resulted in improvement in dogs that also have inflammation of the esophagus (known as “esophagitis”), inflammation of the stomach (known as “gastritis”) and/or inflammation of the upper small intestine (known as the “duodenum”; condition known as “duodenitis”)

Follow-Up Care

Patient Monitoring

  • Post-operatively, 24-hour monitoring to observe for airway swelling and obstruction, which may require surgical incision into the windpipe (temporary tracheostomy)
  • Breathing rate, effort, heart rate, pulse quality, mucous membrane color, capillary refill time, temperature, and other physical parameters should be monitored

Preventions and Avoidance

  • Selection by breeders for dogs without severe conformational changes—may be difficult because breed standards encourage these structural changes
  • Avoid risk factors, particularly weight gain

Possible Complications

  • Overheating and heat stroke
  • Aspiration pneumonia (inflammation of the lungs, caused by accidentally inhaling food, vomit, or liquids into the airways)
  • Death in about 10% of affected pets as a result of airway disease
  • Most common post-operative complication is airway swelling and obstruction within the first 24 hours, may necessitate surgical incision into the windpipe (temporary tracheostomy)
  • Continued breathing difficulty after corrective surgery
  • Excessive shortening of the soft palate resulting in aspiration of food contents into the nasal cavity due to inability to close off the area between the nose and throat (known as the “nasopharynx”) during swallowing

Expected Course and Prognosis

  • Prognosis is good for improvement in breathing (80% of cases have good to excellent results following surgery) but airway is still far from normal
  • Prognosis better for dogs other than English bulldogs and for dogs that have correction of narrowed nostrils (stenotic nares) and elongated soft palate during same surgery
  • Without surgery, prognosis is poor due to continued progression of brachycephalic airway syndrome
  • Lifelong avoidance of risk factors recommended to decrease chance of developing clinical signs or worsening of disease

Key Points

  • Avoidance of risk factors is critical
  • Dogs with brachycephalic airway syndrome are at increased anesthetic risk, and an even higher risk occurs if they also have obesity, heart disease, or aspiration pneumonia (inflammation of the lungs, caused by accidentally inhaling food, vomit, or liquids into the airways)
  • Surgery often improves the clinical signs but does not result in a completely normal airway

Corneal and Scleral Lacerations

Corneal and Scleral Lacerations – An Overview

  • “Corneal” refers to the cornea; “scleral” refers to the sclera of the eye
  • The “cornea” is the clear outer layer of the front of the eye; the “sclera” is the white part of the eye, it is composed of a tough covering that protects the eyeball
  • “Penetrating” injury—a wound or foreign body that enters, but does not completely pass through the cornea or sclera; it also is known as a “non-perforating” injury
  • “Perforating” injury—a wound or foreign body that completely passes through the cornea or sclera; greater risk of vision loss than with penetrating injury
  • “Simple”—involves only the cornea or sclera; may be penetrating or perforating; other eye structures are intact (that is, not injured)
  • “Complicated”—a type of perforating injury; involves other eye structures in addition to the cornea or sclera; may involve the uvea (the entire middle layer of the eyeball that contains the blood vessels; it is composed of the iris [the colored or pigmented part of the eye], the ciliary body [the area between the iris and the choroid], and the choroid [located under the back part of the eye—the retina); the vitreous (the clear, gel-like material that fills the back part of the eyeball [between the lens and the retina]); or the retina (back part of the eye that contains the light-sensitive rods and cones and other cells that convert images into signals and send messages to the brain, to allow for vision); may also have trauma to the lens leading to cataracts or lacerations to the eyelids
  • The pupil is the circular or elliptical opening in the center of the iris of the eye; light passes through the pupil to reach the back part of the eye (known as the “retina”); the iris is the colored or pigmented part of the eye—it can be brown, blue, green, or a mixture of colors

Signs/Observed Changes in the Pet

  • Varies with tissues affected
  • Usually sudden (acute) onset of signs
  • Often a history of running through heavy vegetation, being hit by gunshot pellets or other projectiles, or being scratched by a cat
  • Trauma itself may not be observed
  • Common—corneal, scleral, or eyelid deformity; fluid buildup (known as “edema”) in affected tissues; bleeding (hemorrhage)
  • May see a retained foreign body
  • Lacerations often rapidly seal; may appear only as a blood-filled mass under the moist tissues of the eye (known as a “subconjunctival hematoma”)
  • May also see iris defects; pupil distortion; blood in the anterior chamber of the eye (the front part of the eye, between the cornea and the iris; accumulation of blood known as “hyphema”); cataract (opacity in the normally clear lens, preventing passage of light to the back part of the eye [retina]); bleeding in the vitreous (the clear, gel-like material that fills the back part of the eyeball); separation of the back part of the eye (retina) from the underlying, vascular part of the eyeball (known as the “choroid”; condition known as “retinal detachment”); and protrusion of the eyeball (known as “exophthalmia”)

Causes

  • Blunt or sharp trauma

Risk Factors

  • Preexisting visual impairment
  • Young, naive, or highly excitable pets
  • Hunting or running through heavy vegetation
  • Fighting

Treatment

Health Care

  • Depends on severity
  • Outpatient—if integrity of the eyeball is ensured
  • Sedation—consider for excited or fractious pets
  • When walking—apply an Elizabethan collar and use a harness to avoid increasing pressure in the affected eye

Injuries Considered for Medical Treatment

  • Penetrating or non-perforating wounds with no overriding or gaping of the wound edges—apply an Elizabethan collar; administer antibiotic and/or atropine eye solutions directly to the eye (“topical treatment”)
  • Penetrating or non-perforating wounds with mild gaping of wound edges or shelved edges—apply a therapeutic soft contact lens and an Elizabethan collar; administer antibiotic and/or atropine eye solutions directly to the eye (“topical treatment”)
  • Simple full-thickness, pinpoint corneal perforation with a formed anterior chamber and no uveal prolapse—sedentary pets; use a therapeutic soft contact lens and an Elizabethan collar; apply topical antibiotic and/or atropine ophthalmic solutions; reexamine a few hours after applying the lens and at 24 and 48 hours

Activity

  • Usually confined indoors (cats) or limited to leash walks until healing is complete
  • A harness is preferred to a collar, to reduce pressure on the neck and the risk of increased pressure within the eye (known as “intraocular pressure” or IOP) and leaking through the wound

Surgery

Injuries Requiring Surgical Exploration or Repair

  • Full-thickness corneal or scleral lacerations
  • Complicated injuries
  • Suspected retained foreign body or a scleral rupture involving the back of the eye
  • Simple, penetrating or non-perforating wound with edges that are moderately or overtly gaping and that are long or more than two-thirds the corneal thickness

Injuries Considered for Surgical Exploration or Repair

  • Small, simple, full-thickness corneal lacerations
  • Large conjunctival lacerations; the “conjunctiva” is the moist tissue lining the eye
  • Partial-thickness corneal or scleral lacerations in an active pet

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.

Antibiotics

  • Complicated wounds, those with retained plant material, and those caused by blunt trauma with tissue devitalization—infection common
  • Bacterial infection/inflammation of the tissues within the eyeball (known as “endophthalmitis”)—seen in 5% to 7% of pets with perforations; very rare in wounds that only penetrate, but do not perforate the cornea
  • Penetrating wound—topical (applied to the eye) antibiotics alone (such as neomycin, polymyxin B, and bacitracin) or gentamicin solution usually sufficient
  • Perforating wounds—systemic (administered by injection or by mouth) ciprofloxacin (dogs); topical (applied to the eye) cefazolin and fortified gentamicin or tobramycin
  • Topical (applied to the eye) ciprofloxacin eye solution—may be used instead of the combination of topical cefazolin and a fortified aminoglycoside

Anti-Inflammatory Drugs

  • Topical (applied to the eye) 1% prednisolone acetate or 0.1% dexamethasone solution—as soon as the wound is sutured or the surface is healing, if no infection is present
  • Systemic (administered by mouth) prednisone—for sutured or healing wounds when inflammation is severe; when the lens or more posterior structures are involved; when the wound is infected or not healing and control of inflammation is mandatory to preserve the eye
  • Topical (applied to the eye) nonsteroidal anti-inflammatory drugs (NSAIDs)—flurbiprofen or one of several other NSAIDs; may be used if topical steroids are not indicated (for example, infection is present) and control of inflammation is mandatory to preserve the eye

Medications to Dilate the Pupil (Known as “Mydriatics” and to Relieve Eye Pain)

  • 1% atropine eye solution—when significant constriction of the pupil (known as “miosis”) is present or inflammation is identified in the front chamber of the eye (known as “anterior chamber reaction”)

Medications to Relieve Pain (Analgesics)

  • Topical atropine or oral aspirin — may provide sufficient pain relief; use analgesics only as directed by your pet’s veterinarian
  • Butorphanol—dogs and cats; for mild pain
  • Carprofen
  • Tramadol
  • Oxymorphone—dogs and cats; for sudden (acute) severe pain; when sedation is required

Follow-Up Care

Patient Monitoring

  • Deep or long penetrating wounds that have not been sutured and perforating wounds—recheck every 24–48 hours for the first several days to ensure integrity of the eyeball, to monitor for infection, and to check control of eye inflammation
  • Superficial penetrating wounds—usually rechecked at 3- to 5-day intervals, until healed
  • Antibiotic therapy—altered according to bacterial culture and sensitivity results

Preventions and Avoidance

  • Take care when introducing new puppies to households with cats that have front claws
  • Minimize running through dense vegetation
  • Consider having a bottle of saline eyewash to irrigate or flush debris from the eye
  • Minimize visually impaired or blind dogs’ exposure to dense vegetation

Possible Complications

  • Loss of the eye or vision
  • Long-term (chronic) eye inflammation or pain

Expected Course and Prognosis

  • Most eyes with corneal lacerations or having a retained corneal foreign body are salvageable
  • The further back the injury is located in the eye, the poorer the prognosis for retention of vision
  • Poor prognosis—involvement of the sclera (the white part of the eye, it is composed of a tough covering that protects the eyeball) or uvea (the entire middle layer of the eyeball that contains the blood vessels); no light perception; perforating injuries involving the lens; significant bleeding into the vitreous (the clear, gel-like material that fills the back part of the eyeball); or separation of the back part of the eye (retina) from the underlying, vascular part of the eyeball (retinal detachment)
  • Penetrating injuries usually better prognosis than perforating injuries
  • Blunt trauma carries a poorer prognosis than sharp trauma

Key Points

  • The full extent of the injury (cataracts, retinal detachment, infection) may not be apparent until several days or weeks after the injury; therefore, long-term follow-up is necessary