Experimental papilledema in the dog induced by a salicylanilide

Abstract Dogs given 3–11 doses po of 100 mg/kg/day of rafoxanide [3,5-diiodo-3′-chloro-4′-( p -chlorophenoxy) salicylanilide] developed bilateral equatorial cataracts, papilledema, vacuolation of the optic nerve, optic chiasma, white matter of the brain and spinal cord and focal vacuolation of sciatic nerve. Other toxicologic manifestations included increased glutamic oxaloacetic transaminase and serum alkaline phosphatase, neutrophilia, lymphopenia, focal hepatic necrosis and lymphoid necrosis in lymph nodes and the intestine. The pathogenesis of the ocular and neural lesions was related to increased cerebrospinal fluid pressure probably due to an increased amount of fluid in the cranial cavity, brain swelling and meningeal inflammation around optic nerve and optic chiasma.