Dysautonomia in Dogs: A Retrospective Study

Abstract

Dysautonomia was diagnosed in 11 young (median age, 14-months), predominantly 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 light reflexes, decreased tear production, dry mucous membranes, weight loss, and decreased anal tone were present in over 75% of affected dogs. Ocular pharmacological testing with a dilute (0.1%) solution of pilocarpine was used to demonstrate iris sphincter receptor function in all dogs. A low-dose 10.0375 mglkg SC) bethanechol test and pharmacological ysautonomia is a general term for dysfunction of the D autonomic nervous system. It can be secondary to other systemic or neurological diseases,'-6 but primary dysautonomias are relatively rare in both people and animals. Equine dysautonomia (grass sickness) is the most common of the dysautonomias in animals and was described in horses in the British Isles during the early twentieth centu~-y.~-~ Dysautonomia has since been reported in nondomestic equines and in wild European hares.''-'' Dysautonomia was described in cats in the United Kingdom in 1982.''-15 Additional affected cats, were later identified throughout Europe, Scandinavia, New Zealand, and the United States.''-*' The first case of canine dysautonomia was reported in England in 1983." Since then, 9 other dogs with dysautonomia have been reported from Scotland:' Belgium,".25 Nor~ay:~,'~ and France?' In 1991, a dog with suspected dysautonomia was reported in the United States, but the diagnosis was not confirmed histol~gically.~~ The purpose of this report is to describe and correlate the clinical and pathological findings associated with this neurological disorder, describe diagnostic tests of the autonomic nervous system that are helpful in obtaining an antemortern diagnosis of dysautonomia, and compare canine dysautonomia with other known dysautonomias in animals. Patients and MethodsTen of the 11 dogs studied were presented to the University of Missouri for evaluation of autonomic dysfunction ( Table 1). Physical and neurological examinations, and ocular pharmacological testing were performed by the authors in these 10 dogs. Dog 3 died before referral, and for this patient the results of the physical and neurological examinations and of ocular pharmacological testing obtained by the referring veterinarian were recorded. Necropsies were performed at the University of Missouri on all 11 dogs. Electrocardiographic, radiographic, clinicopathologic, cerebrospinal fluid (CSF) analysis, and ultrasonographic findings were reviewed when available. Cisternal CSF was analyzed for total nucleated cell count, RBC, protein concentration, Pandy reaction, and color and transparency prior to and after centrifugation.Physiological and pharmacological testing was performed in patients prior to euthanasia or death. One to 2 drops of a 0. so that urinary bladder distention was subjectively quantified ultrasonographically before and after voluntary ...

Five cases of canine dysautonomia in England (2004 to 2006)

“…Among the most consistent history and physical examination findings were the presence of acute‐onset vomiting, diarrhoea, depression, inappetence, reduced or absent anal tone, absence of PLR and lacrimal secretion, mydriasis and NMP, which is consistent with previous reports (Longshore and others 1996, Berghaus and others 2001, Harkin and others 2002). Although none of the dogs had an absolute bradycardia, heart rate remained at or below 120 bpm throughout the period of hospitalisation in all dogs.…”

“…Two cases were Labrador retrievers, and in three previous studies, an apparent breed predisposition in Labrador retrievers was reported (Longshore and others 1996, Berghaus and others 2001, Harkin and others 2002). This might reflect the popularity of this breed in rural areas as a rural environment was also found to be a risk factor (Longshore and others 1996).…”

“…Two cases were Labrador retrievers, and in three previous studies, an apparent breed predisposition in Labrador retrievers was reported (Longshore and others 1996, Berghaus and others 2001, Harkin and others 2002). This might reflect the popularity of this breed in rural areas as a rural environment was also found to be a risk factor (Longshore and others 1996). Although no sex predilection has been described, canine dysautonomia typically appears to affect younger dogs (Harkin and others 2002, O’Brien and Johnson 2002) which is also apparent in the present report, with the exception of dog 5.…”

“…The cause or, indeed, causes of canine dysautonomia remain unknown (Longshore and others 1996, Berghaus and others 2001, Harkin and others 2002, O’Brien and Johnson 2002). Interestingly, inflammatory changes were detected on CSF analysis of case 5, possibly suggesting the presence of concurrent disease (apart from the dysautonomia) causing or being the result of dysautonomia.…”

“…Canine dysautonomia was first described in England by Rochlitz and Bennett (1983). Although individual cases have been reported in Scotland (Pollin and Sullivan 1986, Jamieson and others 2002), Norway (Presthus and Bjerkas 1987), Belgium (Schrauwen and others 1991, 1993), Germany (Schulze and others 1997) and Greece (Adamama‐Moraitou and others 2006), canine dysautonomia is less commonly reported in Europe compared with the high numbers reported in the USA (Wise and Lappin 1991, Longshore and others 1996, Berghaus and others 2002, Harkin and others 2002). Within the UK, two cases have been reported from Scotland (Jamieson and others 2002), although the case described by Rochlitz and Bennett (1983) remains the only case from England.…”