Misc. Flashcards
Misc. (burns, ophthalmology, envenomation, hyper/hypothermia, procedures/equipment)
What is heatstroke in dogs?
A nonpyrogenic increased body temperature above 104°F (40°C) with systemic signs.
Heatstroke is life-threatening and can affect dogs of any age, breed, or gender.
What is the role of the thermoregulatory center in dogs?
Maintains body temperature within a narrow range or set point.
Located in the anterior hypothalamus.
What differentiates pyrogenic from nonpyrogenic hyperthermia?
Pyrogenic hyperthermia involves an increase in the hypothalamic set point; nonpyrogenic does not.
Active cooling is safe in nonpyrogenic hyperthermia.
What are the methods of cooling for dogs?
- Evaporation
- Conduction
- Convection
- Radiation
How does evaporation help in thermoregulation in dogs?
Occurs through panting, dispelling heat via evaporation of water from the tongue.
Most effective when ambient temperature is below 89.6°F (32°C).
What is the definition of heat stress in veterinary patients?
Includes discomfort and physiologic strain with normal core body temperature.
It is rarely recognized in veterinary patients.
What are the main clinical signs of heatstroke in dogs?
- Collapse
- Tachypnea
- Shock
- Inappropriate mentation
- Signs of coagulopathy
What is exertional heatstroke?
Occurs during exercise, more common in dogs not acclimated to their environment.
Acclimation can take up to 60 days.
What is nonexertional heatstroke?
Results from exposure to increased environmental temperatures without adequate cooling.
Examples include being left in a parked car.
What is the acute-phase response?
A coordinated cellular response during inflammatory events to protect tissues from excessive heat.
Stimulated during nonpyrogenic hyperthermia.
What are negative acute-phase proteins?
Proteins that decrease by 25% during an acute-phase response, such as albumin.
Levels can decrease due to GI or renal loss or decreased production.
What are positive acute-phase proteins?
- C-reactive protein
- Serum amyloid A
What is the effect of heatstroke on the central nervous system?
Increased susceptibility to cytotoxicity, resulting in injury and death of neurons, cerebral edema, and hemorrhage.
Severity depends on temperature and duration.
What cardiovascular changes occur during heatstroke?
Initially increased cardiac output, peripheral vasodilation, and central vasoconstriction, followed by hypotension and shock.
Blood circulation is compromised.
What are the common diagnostic findings in heatstroke patients?
- Increased creatinine
- Increased lactate
- Decreased platelets
- Increased hemoglobin concentration
What is the most important aspect of treatment for heatstroke?
Active cooling.
Early cooling efforts significantly improve prognosis.
True or False: Dogs may present normothermic or hypothermic with heatstroke due to prior cooling efforts.
True
Fill in the blank: Heatstroke in dogs can be classified as _______ or nonexertional (classical).
exertional
What is the most important aspect of treatment for heatstroke?
Active cooling
Active cooling may not prevent all deleterious effects of heatstroke but is crucial for treatment.
What is the mortality rate for dogs that are actively cooled before reaching the hospital compared to those that are not?
19% for cooled dogs vs. 49% for non-cooled dogs
What should be avoided during the treatment of heatstroke?
- Use of ice
- Gastric lavage
- Cold water enemas
- Shivering
Using ice causes peripheral vasoconstriction, gastric lavage poses aspiration risks, and cold water enemas may damage the GI tract.
What is an effective cooling method for dogs experiencing heatstroke?
Directing a fan toward the dog and applying cool or tepid water to the skin
At what body temperature should active cooling be discontinued to avoid rebound hypothermia?
103.5°F to 104°F (39.7°C–40°C)
What is the cornerstone of heatstroke treatment?
Intravenous fluids
What type of fluids should be administered upon arrival of a heatstroke patient?
Room temperature crystalloids
When should colloids be considered in heatstroke treatment?
If crystalloids do not adequately maintain intravascular volume or if the patient is hypoalbuminemic
What are some recommended antibiotics for heatstroke patients?
- Ampicillin
- Cefazolin
- Enrofloxacin
- Metronidazole
These antibiotics help prevent bacterial translocation due to GI damage.
What medications are beneficial for GI tract support in heatstroke patients?
- Antiemetics (metoclopramide, dolasetron, maropitant)
- Proton pump inhibitors (omeprazole, pantoprazole)
- H2 receptor antagonists (famotidine, ranitidine)
- Sucralfate
These medications help manage nausea and prevent gastric ulceration.
What is mannitol used for in heatstroke treatment?
To decrease intracranial pressure and improve cerebral microcirculation
What is the prognosis for heatstroke patients primarily dependent on?
Length of time the patient was hyperthermic and the highest body temperature experienced
True or False: The development of ventricular arrhythmias is a negative prognostic indicator in heatstroke patients.
True
What are some prevention strategies for heatstroke in dogs?
- Ensure availability of shade and drinking water
- Exercise dogs during cooler periods
- Never leave dogs alone in closed vehicles
- Acclimate dogs to warm temperatures
- Surgically address upper airway obstructions
Owner education is crucial for preventing heatstroke.
What should be monitored during the hospitalization of a heatstroke patient?
- Neurologic status
- Heart rate and pulse quality
- Respiratory rate and effort
- Blood pressure
- ECG
- PT and aPTT
- Packed cell volume and total protein
- Blood glucose and electrolytes
- Lactate and acid–base balance
- Urine output
Serial monitoring can help assess response to therapy, particularly lactate clearance.
What is the normal urine output for a dog on IV fluids?
At least 1 to 2 mL/kg/hour
What is a positive prognostic indicator for dogs that have suffered heatstroke?
Return of normal CNS function
What is heatstroke in dogs?
An acute, life-threatening emergency characterized by nonpyrogenic elevation in body temperature resulting in direct thermal injury to body tissues
What are the key clinical features of heatstroke?
- Metabolic acidosis
- Oliguric renal failure
- Coagulation abnormalities
- Neurologic disturbances
What are common clinical signs observed in dogs with heatstroke?
- Excessive panting
- Hyperemia
- Hypersalivation
- Tachycardia
- Various neurologic signs
What laboratory changes are associated with heatstroke?
- Hemoconcentration
- Elevated liver enzymes
- Electrolyte changes
- Prolonged clotting times
- Azotemia
- Hypoglycemia
What is the primary goal in managing heatstroke?
To rapidly cool the core body temperature while preventing further damage to vital organs
What temperature is considered indicative of heatstroke in dogs?
A core body temperature higher than 106˚F (41.1˚C)
What are some risk factors for heatstroke in dogs?
- Exercise
- Poor ventilation in enclosed areas
- Hot weather conditions
True or False: Systemic infections with fever usually cause panting and hypersalivation.
False
What should owners do if they suspect their dog is experiencing heatstroke?
Institute cooling measures immediately before transporting to a veterinarian
What are some clinical signs that may indicate severe neurologic involvement in heatstroke?
- Ataxia
- Loss of consciousness
- Seizures
- Coma
Fill in the blank: The most common clinical sign in patients with heatstroke is _______.
excessive panting
What are the common clinicopathologic findings in heatstroke?
- Hemoconcentration
- Low blood glucose
- Elevated BUN and creatinine levels
- Electrolyte abnormalities
What kind of abnormalities may be present in coagulation due to heatstroke?
- Thrombocytopenia
- Coagulation factor disruption
- Disseminated intravascular coagulation (DIC)
What electrolyte imbalance is frequently present in canine heatstroke?
Hypernatremia due to pure water loss
What should be avoided when cooling a dog with heatstroke?
Ice water baths
What is a recommended initial fluid therapy for dogs with heatstroke?
Crystalloid fluids, such as balanced electrolyte solutions
What is the significance of monitoring blood gases in heatstroke patients?
To assess for respiratory alkalosis or metabolic acidosis
What are some potential causes of hyperthermia that can be confused with heatstroke?
- Eclampsia
- Tremorgenic toxins
- Malignant hyperthermia
What is the recommended temperature to stop aggressive cooling efforts in heatstroke patients?
103˚F (39.4˚C)
What clinical findings may indicate disseminated intravascular coagulation (DIC) in dogs with heatstroke?
- Petechial hemorrhages
- Ecchymosis
- Tachycardia with thready pulses
True or False: Owners should wait to cool their dog until reaching the veterinary clinic.
False
What are common signs of renal impairment in dogs with heatstroke?
- Elevated BUN and creatinine levels
- Myoglobinuria
What is the initial type of fluid therapy recommended for cardiovascular shock?
Crystalloid fluids (e.g., balanced electrolyte solutions)
These fluids are preferred to rehydrate the interstitium.
When are colloids typically used during heatstroke treatment?
During the initial resuscitation period, but must be followed by crystalloid therapy
Examples of colloids include hetastarch, dextran, and plasma.
What is the recommended dose reduction when using both crystalloids and colloids together?
Reduce the dose of crystalloids by 40% to 60%.
What condition may benefit from the use of colloids in heatstroke treatment?
Hypoalbuminemia and decreased colloid osmotic pressure.
What type of blood product may be necessary to treat anemia after initial resuscitation?
Whole blood or packed red blood cell transfusions.
What factors should be monitored to evaluate fluid therapy effectiveness?
Heart rate, pulse quality, mucous membranes, capillary refill time, arterial blood pressure.
True or False: Prophylactic antibiotic therapy is universally recommended in heatstroke cases.
False
It is controversial due to potential resistance and worsening endotoxemia.
What should be supplemented in IV fluids if hypoglycemia is present?
Dextrose.
Which drug is recommended for gastrointestinal protection in heatstroke treatment?
Cimetidine or ranitidine.
What is the recommended treatment for Disseminated Intravascular Coagulation (DIC) in dogs?
Fresh-frozen plasma and possibly heparin.
How should metabolic acidosis be corrected in heatstroke patients?
Sodium bicarbonate can be given if acidemia persists after adequate resuscitation.
What is the recommended treatment for hypokalemia?
Potassium chloride, no more than 0.5 mEq/kg/hr IV.
What should be monitored to prevent acute renal failure during heatstroke treatment?
Urine output.
What is the first step in treating hypotension after fluid resuscitation?
Consider dopamine or dobutamine hydrochloride.
What are the potential complications associated with corticosteroid use in heatstroke treatment?
Gastric ulceration, immunosuppression, exacerbation of renal damage.
Why are NSAIDs contraindicated in heatstroke treatment?
They can cause severe hypothermia, gastrointestinal ulceration, prolonged bleeding times, and bone marrow suppression.
What is the survival rate reported for dogs with heatstroke in some cases?
As high as 64%.
List at least three unfavorable prognostic criteria for heatstroke in dogs.
- Coma or progressive neurologic deterioration
- Persistent hypoglycemia
- Worsening azotemia despite adequate fluid therapy.
What is the key to successful treatment and recovery from heatstroke?
Early recognition and treatment.
Fill in the blank: To prevent exertional heatstroke, outdoor duties should be scheduled during the _______ parts of the day.
[cooler]
What is crucial for monitoring during the first 24 to 48 hours after heatstroke treatment?
Continuous critical monitoring of acid–base status, packed cell volume, white blood cell count, total solids, BUN, and platelet count.
What should owners be educated about to prevent heatstroke in their dogs?
The risks of confining or exercising dogs in hot environments.
What is the primary goal of treatment for patients with heatstroke?
Lower the core body temperature as quickly as possible.
Which of the following is not a clinical pathologic finding in canine heatstroke?
Decreased alkaline phosphatase
DIC is suspected if there is _______.
Thrombocytopenia, prolonged prothrombin time, and elevated activated partial thromboplastin time.
True or False: Immersing the body totally in ice cold water is an accepted method of cooling during heatstroke.
False
What are common electrolyte changes that occur during heatstroke?
Hypernatremia and hyperchloremia
Unfavorable criteria associated with poorer outcomes of dogs with heatstroke include all of the following except _______.
Persistently elevated alanine transaminase
Heatstroke in dogs can be prevented primarily by _______.
Educating owners concerning the risks of confining animals outdoors
How long may it take for some dogs to fully acclimate to a hot environment?
28 days
Which of the following physical examination findings is commonly seen in dogs with heatstroke?
Excessive panting
Fill in the blank: Patients with oliguric or anuric renal failure are best treated with _______.
Dopamine and furosemide
What are the common clinical signs of heatstroke in dogs?
- Excessive panting
- Hypersalivation
- Hyperemic mucous membranes
- Tachycardia
True or False: Providing adequate ventilation and shade and allowing free access to cool drinking water is a method to prevent heatstroke.
True
What is the effect of glucocorticoids in rat heatstroke as mentioned in the text?
Reduce interleukin-1 concentration and result in neuroprotective effects
What is the role of colloids in maintaining fluid balance according to the text?
Critical need for colloids: Maintaining fluid balance
What are the acute effects of massive transfusion of a bovine hemoglobin blood substitute in a canine model of hemorrhagic shock?
Effects described in the study by Harringer et al.
What is a common consequence of heatstroke related to coagulation as mentioned in the text?
Disseminated intravascular coagulation (DIC)
Fill in the blank: Malignant hyperthermia in dogs is discussed in the work of _______.
Nelson TE
What is the significance of the study by Lee-Chiong Jr TL regarding temperature regulation disorders?
Disorders of temperature regulation
