How is dysautonomia diagnosed?
A clinical diagnosis is often made based on the presence of clinical signs that are typical of this disease. There are a couple of ancillary diagnostic tests that may be helpful in making the diagnosis. Instillation of dilute (0.05-0.1%) pilocarpine drops in the eye of an affected dog will usually result in pupillary constriction within about 30 minutes. Some normal dogs can also respond to this concentration of pilocarpine, although it usually takes them 45-60 minutes. A subcutaneous injection of low-dose bethanechol (0.0375 mg/kg) can also be used to see if it improves the dog’s ability to urinate. Neither of these tests are specific for dysautonomia, but they can be used to rule-out an inability of the iris and detrusor muscles to respond to acetylcholine. Histologic examination of autonomic ganglia by a qualified pathologist is the best way to confirm a diagnosis of dysautonomia.
