Overview
- Failure of autonomic function in multiple organs with minimal motor or sensory involvement.
- Young adult, rural, Midwestern dogs at greatest risk.
- Treatment is symptomatic and the prognosis guarded.
Signalment
- Dog and less commonly cat.
- No breed or sex predilection.
- Median age is 18 months but any age animal may be affected.
Signs
- Acute to subacute onset (5–14 days).
- Various combinations of signs may be present but both sympathetic and parasympathetic signs in various organs are necessary to be confident of a diagnosis.
- Sensory or motor deficits are minimal.
Presenting Complaints
- Most commonly GI signs of vomiting or regurgitation, diarrhea, or occasionally constipation.
- Straining to urinate and dribbling urine.
- Photophobia and third-eyelid elevation.
- Dyspnea, coughing, and purulent nasal discharge.
- Depression, anorexia, and weight loss.
Examination Findings
- Variable combinations of autonomic dysfunction.
- Loss of anal sphincter tone.
- Dry nose and mucous membranes; lack of tear production.
- Distended, easily expressed bladder.
- Pupils midrange to maximally dilated with no pupillary light reflex but intact vision.
- Third-eyelid elevation, ptosis, and enophthalmos.
- Lack of gut sounds and occasional abdominal pain.
- Heart rate and blood pressure typically in the low end of normal range but do not rise in response to stress.
- Secondary aspiration pneumonia or rhinitis.
- Cachexia.
- Occasionally mild proprioceptive deficits or weakness.
Causes & Risk Factors
- Cause unknown.
- Highest incidence in Missouri, Oklahoma, and Kansas as well as Wyoming and northern Colorado, but occasional cases reported throughout United States.
- Free-roaming, rural dogs at greatest risk.
