DYSAUTONOMIA IN DOGS - A RETROSPECTIVE STUDY

Dysautonomia was diagnosed in 11 young (median age, 14-months), predom inantly medium- to large-breed dogs from 1988 to 1995. Clinical signs caused by autonomic dysfunction of the urinary, alimentary, and ocular systems were most common. Dysuria, mydriasis, absence of pupillary li ght reflexes, decreased tear production,dry mucous membranes, weight l oss, and decreased anal tone were present in over 75% of affected dogs . Ocular pharmacological testing with a dilute (0.1%) solution of pilo carpine was used to demonstrate iris sphincter receptor function in al l dogs. A low-dose (0.0375 mg/kg SC) bethanechol test and pharmacologi cal testing with phenylephrine and epinephrine also demonstrated choli nergic and adrenergic receptor function in 4 dogs. All dogs died or we re euthanized as a result of autonomic dysfunction. Neuronal depletion , with associated gliosis and minimal inflammation were noted histolog ically in the autonomic ganglia of each dog. The pelvic, ciliary, celi ac, cranial cervical, and cranial and caudal mesenteric ganglia were a ffected in all dogs. The cause of autonomic failure in these dogs was not determined. Copyright (C) 1996 by the American College of Veterina ry Internal Medicine.