Case 2
An 11 week-old, 7.4 kg female intact mixed breed dog was presented for
suspected pit viper envenomation. While outside, the puppy cried out,
became lame on the left forelimb, and was evaluated at an emergency
hospital within 40 minutes. The temperature, heart and respiratory rates
were 39⁰C (102.3⁰F), 280 beats/min, and 80 breaths/min, respectively.
The puppy was laterally recumbent, obtunded, and had weak pulses despite
a systolic blood pressure of 150 mm Hg. Severe swelling with two
actively bleeding puncture wounds and ecchymoses were found on the left
shoulder. The pain score* was 4/4. Clinicopathologic
abnormalities included: mild hyperlactatemia (2.5 mmol/L, reference
range 0.4-1.5 mmol/L), anemia (PCV 27%, reference range 33-55%),
severe thrombocytopenia (0-1 platelet/HPF with no clumping, reference
range >10/HPF), and hypocoagulability (ACT 208 s, reference
range 80-120 s). The SSS was 10/20. Two 15 mL (2 mL/kg) IV boluses of
hypertonic saline§§ were administered followed by a 20
mL/kg IV bolus then 3 mL/kg/hr IV LRS¶. One vial of
F(ab)2 antivenom§ was diluted in 60 mL
0.9% salineǁ and administered IV over 20 minutes. An
hour later, a repeat ACT was >999s (reference range
80-120s) and the SSS increased to 12/20. Two additional vials of diluted
F(ab)2 antivenom§ were administered IV
over an hour. Three hours post-presentation, the SSS remained 10/20 and
the ACT was >999s (reference range 80-120s); therefore, a
fourth vial of diluted F(ab)2antivenom§ was administered IV over an hour. The puppy
remained tachycardic (230-270 beats/min) and normotensive; 0.2 mg/kg
methadone** IV was administered. Five hours
post-presentation, the PCV/TS was 20% (reference range 33-55%) and 34
g/L (reference range 65-80 g/L; 3.4 g/dL, reference range 6.5-8 g/dL),
respectively. Two additional vials of diluted F(ab)2antivenom§ were administered. Approximately six hours
post-presentation and after six vials of antivenom, the SSS decreased to
9/20 and mentation improved.
Thirteen hours post-presentation, the skin proximal to the bite site
blackened. The puppy remained tachycardic (260 beats/min) with strong
pulses, mucus membranes were pale, and non-localizing pain was evident
on abdominal palpation. Repeat clinicopathologic parameters showed
anemia [HCT 17%, reference range 33-55%; hemoglobin 55 g/L, (5.5
g/dL); reference range 140-260 g/L (14-26 g/dL)], hypokalemia (3.73
mmol/L; reference range 3.98-4.41 mmol/L), hyponatremia (136.7 mmol/L;
reference range 146-151 mmol/L), and mild hyperlactatemia (2.3 mmol/L;
reference range (0.4-1.5 mmol/L). Hypocoagulability resolved (ACT 74 s;
reference range 80-120 s) and the puppy was hypertensive at 170 mm Hg.
An IV fentanylǁǁ constant rate infusion (CRI) at 2
µg/kg/hr and ampicillin sulbactam¶¶ 30 mg/kg IV q8h
was begun. Three vials of diluted F(ab)2antivenom§ were administered IV as a CRI over 4 hours.
The SSS 24 hours after admission was 6/20. The puppy began to eat, and
the antibiotic was transitioned to amoxicillin/clavulanic
acid*** 125mg (16.8 mg/kg) PO q12h. Repeat PCV/TS were
13% (reference range 33-55%) and 40 g/L (4 g/dL) [reference range
65-80 g/L (6.5-8 g/dL)], respectively. A packed red blood cell
transfusion (15.4 mL/kg) was administered over four hours. Two hours
post-transfusion the PCV/TS were 23% (reference range 33-55%) and 42
g/L (4.2 g/dL) [(reference range 65-80 g/L (6.5-8 g/dL)],
respectively. Fentanylǁǁ CRI was discontinued and
tramadol§§§ was started at 25 mg (3.4 mg/kg) PO q12h.
The puppy received one 45-minute hyperbaric oxygen chamber treatment
prior to discharge. By Day 4, the bite wound had well demarcated
margins, but did not progress to sloughing.