Index case supporting the need to identify BSA-specific IgE levels in commercial plasma.
A colt of unknown gestational age was born to a malnourished dam with little to no udder development nor colostrum/milk production. The owner administered a commercial powdered bovine/multi-species colostrum supplement3 orally within the first 2 hours of life. Subsequently, the colt was examined and evaluated for transfer of passive immunity status. An IgG test4 was performed at 12 hours of age, which revealed complete failure of transfer of passive immunity (0 mg/dL IgG). The owners elected to continue supplementing the foal on the farm with the powdered colostrum product despite recommendations that it was unlikely to result in adequate transfer of passive immunity. At 24 hours of age a recheck IgG test4 measured an IgG level of 400 mg/dL IgG, consistent with ongoing partial failure of transfer of passive immunity. Once these results were provided, the owners elected to have the attending clinician perform a plasma transfusion with 1L (22 ml/kg) of commercial high immunoglobulin equine plasma.1 Plasma was thawed according to the label instructions while an intravenous catheter was placed into the left jugular vein. Initial physical examination performed was within normal limits. Plasma administration was initiated at a very slow rate initially of 0.05 ml/kg/minute (1 drop/2-3 seconds). Temperature, heart and respiratory rates were measured at 3-5 minute intervals. Signs of colic, dyspnea and urticaria were monitored for continuously. With no evidence of an adverse reaction, the administration rate was slowly increased to 0.15 ml/kg/minute (1 drop/second) over the next 5-10 minutes. At 15 minutes the rate was increased to approximately 0.38 ml/kg/minute (2-3 drops/second), at this point the foal quickly began to show colic signs. The plasma infusion was stopped immediately. Crackles were auscultated in all lung fields and pink-tinged foamy nasal discharge became evident bilaterally suggestive of pulmonary edema. The foal became apneic after one minute. Intravenous epinephrine5 (0.02 mg/kg) was administered along with furosemide6 (1 mg/kg) and dexamethasone7 (0.15 mg/kg). The foal did not respond to emergency medications or attempts at field cardiopulmonary resuscitation and died within 3 minutes following discontinuation of the plasma transfusion.
Based on the history and response of this foal to plasma transfusion, it was suspected that this foal suffered from BSA-associated hypersensitivity. This outcome was consistent with previous anecdotal reports of foals consuming powdered colostrum followed by IV commercial plasma infusion, which has been reported to result in fatal reactions. The remaining commercial plasma administered to this foal was saved at -80˚ C for further analysis.