Page 184 - Cote clinical veterinary advisor dogs and cats 4th

74 Aortic Thromboembolism, Feline

urinary retention) from first-generation hospital). This can help confirm exposure but Recommended Monitoring
antihistamines; rare with second-generation is not helpful clinically. Body temperature, heart rate and blood pres-
VetBooks.ir ○ Higher doses of antihistamines may have TREATMENT PROGNOSIS & OUTCOME
sure, hydration status
drugs
stimulatory CNS effects (excitation,
agitation, hyperactivity), particularly in
young animals. Hyperthermia may be Treatment Overview • Good with prompt decontamination and
Decontamination of patient if asymptomatic
identified. (induce emesis and give activated charcoal); control of CNS and cardiovascular effects
• Dextromethorphan: as above; at high doses, control CNS, GI signs, hyperthermia, cardio- • Guarded with poorly controlled seizures
disorientation, hallucination, stimulatory, vascular effects, and provide supportive care as
and dissociative effects; facial edema needed. PEARLS & CONSIDERATIONS
Etiology and Pathophysiology Acute General Treatment Comments
• Antihistamines: H1-receptor antagonists are Decontamination of patient (any high-dose • A CM may contain one active ingredient or
quickly absorbed orally; delayed gut empty- CM) (p. 1087) many.
ing following anticholinergic effects of • Emesis in patients not showing any clinical • Antihistamines used therapeutically in dogs
antihistamines may delay absorption. signs; most effective when used within 1 and cats can cause mild sedation at the
• Dextromethorphan: a non-addicting opioid, hour of exposure recommended dose that does not require
acts centrally by elevating cough threshold. • Activated charcoal 1-2 g/kg PO mixed with treatment. They also possess some antiemetic
It also has dopamine receptor blocking a cathartic, if dose is high enough that severe effects.
activity and serotonin agonist activity at signs are expected • Depending on the dose, presence of decon-
higher doses. • Gastric lavage (p. 1117) for life-threatening gestants (pseudoephedrine) (p. 240), acet-
doses if inducing emesis is not safe, followed aminophen (p. 10), ibuprofen (p. 695), or
DIAGNOSIS by activated charcoal other painkiller may pose a higher risk for
Control CNS signs (antihistamines, dextro- the patient. These medications are usually
Diagnostic Overview methorphan): present at much higher concentrations
The diagnosis is suspected based on history/ • Diazepam 0.5-1 mg/kg IV for CNS excita- compared with antihistamines, cough sup-
evidence of ingestion of antihistamine and/ tion. Note: give slowly IV over 1-2 minutes; pressants, or expectorants.
or CM and presence of gastrointestinal (GI), can aggravate CNS excitation if given rapidly • Stimulatory CNS effects from antihistamines
CNS, or cardiovascular signs within a few • Acepromazine 0.05-0.1 mg/kg IM or IV for can be treated with diazepam and patient
hours. agitation (avoid if patient hypotensive) kept in a semi-dark room for a few hours.
• Cardiovascular effects: beta-blocker (e.g.,
Differential Diagnosis propranolol 0.02-0.06 mg/kg IV; generally Prevention
• Rule out other toxicoses that can cause CNS start low and repeat as needed, with continu- Keep all medications in closed cabinets or
depression, including marijuana, opiates, ous ECG monitoring) for persistent sinus drawers, not on countertops.
antidepressants, benzodiazepines, ethylene tachycardia
glycol, and ivermectin. • Vasopressors may be indicated for severe Technician Tips
• Paradoxical reactions from antihistamines hypotension that does not respond to fluids. Check label to ascertain whether dealing with
can be confused with CNS stimulants such Epinephrine is contraindicated, as it may one or multiple active ingredients.
as amphetamines, pseudoephedrine, ephed- worsen hypotension.
rine, cocaine, and methylxanthines. • Control vomiting: maropitant 1 mg/kg SQ Client Education
q 24h Consult with a veterinarian before giving any
Initial Database • Thermoregulation: cooling fans (hyperther- over-the-counter medications to your animal.
• CBC, serum biochemistry profile: no sig- mia) or heat source (hypothermia) prn
nificant changes expected • Supportive care: IV crystalloid fluids prn SUGGESTED READING
• Heart rate and blood pressure (p. 1065): • Serotonin syndrome (p. 1281): cyprohepta- Christie J: Antitussives and expectorants. In Hovda
increased initially, reduced later dine 1.1 mg/kg PO or per rectum; q 6-8h L, editor. Blackwell’s 5 minute veterinary consult:
• Electrocardiogram (ECG): if arrhythmia for disorientation, agitation in dextromethor- small animal toxicology, ed 2, Ames, IA, 2016,
suspected (p. 1096) phan overdose Wiley, pp 313-319.

Advanced or Confirmatory Testing Behavior/Exercise AUTHOR: Laura Stern, DVM, DABVT
EDITOR: Tina Wismer, DVM, MS, DABVT, DABT
Some antihistamines and their metabolites Limit or confine animals with neurologic effects
can be measured in serum and urine (human to prevent injury.

Aortic Thromboembolism, Feline Client Education
Sheet

BASIC INFORMATION thrombus formation (typically the left side of circulation and obstructs a vessel in an organ
the heart) and the associated clinical sequelae. or tissue.
Definition • Thrombus refers to a concretion of cells and • Thrombi (and subsequent emboli) are most
• Thromboembolism is a well-recognized blood constituents (clot) in a discrete location commonly a sterile matrix of fibrin, platelets,
syndrome caused by occlusion of a systemic in the circulation. and associated red and white blood cells,
artery (typically the aortic trifurcation) by an • Embolus refers to a thrombus or thrombus but tumor or septic emboli are occasionally
embolus that has dislodged from the site of fragment that has traveled through the the cause of thromboembolic disease.

www.ExpertConsult.com