Feline dysautonomia

Feline dysautonomia is characterized by widespread dysfunction of the autonomic nervous system. All breeds and age groups are susceptible. Feline dysautonomia was first reported in 1982 and initially became widespread in the UK; the incidence declined considerably but recently seems to have risen again, although the condition is in a somewhat attenuated form. Cases have been reported throughout Europe, a few have been documented in North America, and sporadic cases have been seen in Dubai, New Zealand, and Venezuela. The etiology is unknown. Dysautonomias in horses, dogs, rabbits, and hares share striking similarities to the condition in cats.

Clinical Findings:

Affected cats initially are mildly obtunded and anorectic and often have upper respiratory signs or transient diarrhea. The onset of more definite signs varies from peracute to chronic. The most common of these signs are dilated, nonresponsive pupils, ptosis, and third eyelid protrusion; a dry rhinarium; reduced lacrimal secretion; esophageal dysfunction with regurgitation; and constipation. Other signs include dry oral mucous membranes, prolapse of the nictitating membrane, bradycardia, and urinary or fecal incontinence. These signs reflect both sympathetic and parasympathetic dysfunction, and there is a wide range in the severity of presenting signs. Somatic signs include anal areflexia. Pelvic limb proprioceptive deficits have been reported but should be carefully differentiated from paresis—ataxia is not a feature of dysautonomia in other species. Clinical pathology findings are nonspecific. Lesions: Necropsy may show megaesophagus, diphtheritic mucous membranes, an atonic bladder, and retention of fecal material. During the first few weeks after onset, chromatolysis and neuronal degeneration of pre- and postganglionic sympathetic and parasympathetic neurons is typical. A very specific distribution of chromatolytic autonomic and somatic lower motor neurons is found in the brain stem and spinal cord. Chronic cases can be difficult to confirm because surviving neurons appear normal, and diagnosis depends on an assessment of their numbers relative to surrounding stromal cells. Diagnosis: Definitive diagnosis depends on histopathologic examination of autonomic ganglia. Clinical confirmation may be aided by contrast radiography (including fluoroscopy) of the esophagus and by reduced lacrimal secretion (<5 10-15="10-15" a="a" although="although" and="and" applied="applied" but="but" by="by" cat.="cat." causes="causes" cornea="cornea" denervation="denervation" dilute="dilute" due="due" effect="effect" eyelid.="eyelid." feline="feline" has="has" healthy="healthy" hypersensitivity="hypersensitivity" leukemia="leukemia" measured="measured" min="min" miosis="miosis" mm="mm" nbsp="nbsp" no="no" on="on" phenylephrine="phenylephrine" pilocarpine="pilocarpine" profound="profound" protruding="protruding" ptosis="ptosis" reverses="reverses" schirmer="schirmer" span="span" tear="tear" test="test" the="the" third="third" to="to" virus="virus" when="when" within="within">infection can cause both anisocoria and urinary incontinence, cats with dysautonomia usually show other clinical signs and are FeLV-negative.