Page 2109 - Cote clinical veterinary advisor dogs and cats 4th

1052 Zinc Phosphide Intoxication

kidney (collect samples in airtight jar) by a ○ Gastric lavage (p. 1117) can be risky PROGNOSIS & OUTCOME
diagnostic laboratory. due to public health hazard. Place a • Good for animals not showing clinical signs
VetBooks.ir Differential Diagnosis in patients in which emesis cannot be • Guarded to poor if cardiac arrhythmias,
cuffed endotracheal tube. Consider only
8-16 hours after exposure
induced (comatose/obtunded animal).
• Toxic: strychnine, metaldehyde, organophos-
phate or carbamate insecticides, arsenic
fluid (use of water can increase phosphine
usually within 6 hours
• Other: primary central nervous system (CNS) Use magnesium hydroxide as lavage shock, or pulmonary edema develop; death
disease (e.g., neoplasia, encephalitis), hepatic liberation). • Fair to good for cases surviving 24 hours
encephalopathy • Control seizures with one of the following:
○ Diazepam 0.5-2 mg/kg IV; repeat as PEARLS & CONSIDERATIONS
Initial Database needed
• Chest radiographs: pulmonary edema ○ Pentobarbital 10-30 mg/kg IV to effect Comments
• Acid-base status: respiratory and metabolic and repeat as needed or phenobarbital • Early vomiting (self-decontamination) may
acidosis 3-30 mg/kg IV to effect reduce risk of serious toxicosis in dogs.
• Electrocardiogram (ECG [p. 1096]): arrhyth- ○ Propofol up to 3-6 mg/kg slow IV to • Human inhalation of phosphine off-gas
mias, nonspecific evidence of myocardial effect, then constant-rate IV infusion during decontamination procedures is
ischemia (e.g., ST-segment elevation or 0.1-0.6 mg/kg/min titrated to effect hazardous. Typical garlic/dead fish odor of
depression) • Stabilize respiratory, cardiovascular, and phosphine may not be detectable at low but
• Baseline CBC and serum chemistries gener- neuromuscular systems. hazardous concentrations for humans.
2+
2+
ally unremarkable but decreased Mg , Ca ○ Supplemental oxygen (p. 1146) • Baits may retain potency for 3 years in a dry
possible ■ Place endotracheal tube if needed, with environment.
• Coagulation profile proper gas evacuation • Toxic dose in dogs and cats is 20-40 mg/kg.
■ If needed, positive-pressure ventilation ○ One tablespoon of 2% pellet bait contains
Advanced or Confirmatory Testing (p. 1185) approximately 180 mg of zinc phosphide,
Freeze gastric contents, vomitus, liver, and ○ Treat hypovolemic shock with crystalloid or a significant risk for a 10-kg dog.
kidney in airtight containers for zinc phosphide colloid fluids; give one-fourth of crystalloid • Delayed hepatic or renal injury is possible
analysis at a diagnostic laboratory. shock dose initially, and repeat as needed 48-72 hours after exposure.
based on hemodynamic parameters up • Fumigants aluminum phosphide and
TREATMENT to the maximum shock dose (80-90 mL/ magnesium phosphide are similar to zinc
kg/h for dogs, 40-60 mL/kg/h for cats). phosphide in toxicity.
Treatment Overview Synthetic colloid dose is approximately
Because of human health risk of phosphine gas, 20 mL/kg/d for dogs and 10-20 mL/kg/d Technician Tips
owners or veterinary staff should decontaminate for cats (adjust based on case parameters). • As with any toxicosis, having the owner bring
asymptomatic patients only in a well-ventilated ○ Monitor acid-base status, and correct the container can confirm active ingredients
area (outside if possible). Additional treatment is metabolic or respiratory acidosis as needed. (label and/or brand name search). Techni-
implemented based on the occurrence of signs: ○ Monitor electrolytes; correct any deficiency cians who speak to owners on the telephone
+
2+
2+
seizure control, treatment of noncardiogenic (Ca , Mg , and K ). should encourage them to bring containers.
pulmonary edema, and supportive care to • Gastrointestinal supportive care Technicians should also recommend the
minimize or prevent renal/hepatic failure, while ○ Antiemetics: maropitant 0.5-1 mg/kg SQ owner take immediate measures to reduce
protecting the veterinarians and staff. q 24h phosphine gas if such exposure possible (see
○ Gastroprotectants: omeprazole 0.5-1 mg/ Acute General Treatment above).
Acute General Treatment kg PO q 12-24h; sucralfate 0.25-1 g PO • Do not wash vomitus down drain because
• Reduce liberation of phosphine gas. q 8-12h water will liberate phosphine gas. Double-bag
○ Magnesium hydroxide 10-60 mL/ANIMAL ○ Monitor serum biochemistry profiles for and dispose of vomitus in the trash.
PO before presentation and vomiting 72 hours for delayed hepatic and renal
induction can increase gastric pH. A com- injury. Client Education
monly available preparation of magnesium • Exogenous scavengers • Keep all baits away from dogs.
hydroxide is Milk of Magnesia. ○ N-acetylcysteine reduced liver injury in • Dogs can dig into mole/gopher holes and
• Decontamination of patient (p. 1087) humans; loading dose 140-280 mg/kg PO retrieve the bait in the yard/garden.
○ Emesis (p. 1188) is indicated in patients or slow IV, then 70 mg/kg PO q 6h for
not showing clinical signs. Apomorphine six treatments. SUGGESTED READING
is preferred 0.04 mg/kg IM or IV or part Knight MW: Zinc phosphide. In Peterson ME, et al,
of a crushed tablet dissolved in water Possible Complications editors: Small animal toxicology, ed 3, St. Louis,
instilled into conjunctival sac. NOTE: Renal, pulmonary, cardiac, and/or hepatic 2013, Saunders, pp 853-864.
Use of 3% hydrogen peroxide 1-2 mL/ compromise; death AUTHOR & EDITOR: Tina Wismer, DVM, MS, DABVT,
kg PO (maximum of 45 mL/DOG) is not DABT
contraindicated for dogs, but it is pos- Recommended Monitoring
sible that its use may enhance liberation Closely monitor vital signs and basic chemistry
of phosphine gas; weigh pros and cons parameters for 72 hours after exposure.
before using in well-ventilated area, if
at all.

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