Grayanotoxin poisoning in three goats

Abstract

Six Nubian goats were exposed to an azalea branch (Rhododendron indica) at the Riverbanks Zoological Park in Columbia, South Carolina. The following day, 3 of the 6 goats were referred to the veterinary hospital of the Riverbanks Zoological Park with bloat, profuse regurgitation, and signs of depression, intermittent head pressing, and fine muscle tremors in the hind limbs. The goats were treated with magnesium hydroxide, activated charcoal, and lactated Ringer's solution and recovered within 24 hours. Definitive diagnosis of grayanotoxin exposure was accomplished by use of liquid chromatography-mass spectrometry analysis of urine and fecal samples. Rhododendron spp are members of the Ericaceae (Heath) family and may contain grayanotoxins, which exert toxic effects by binding to sodium channels in cell membranes and increasing the permeability of sodium ions in excitable membranes. Rhododendron poisoning should be considered in animals with clinical evidence of gastrointestinal tract irritation, cardiac arrhythmias, and neurologic signs.