The Key-Gaskell syndrome--an autonomic polyganglionopathy

A case-control study of grass sickness (equine dysautonomia) in the United Kingdom

A case-control study was performed to investigate the epidemiology of grass sickness in the United Kingdom from 1992 to 1995. Data were collected by means of postal questionnaire when cases of grass sickness were identified. Sets of three questionnaires were posted to owners of, or veterinary surgeons attending, cases of grass sickness, with a request to provide information on the case, on one healthy animal on the same premises as the case and on another healthy animal on other premises. Controls were matched to cases by date of onset. After univariate analyses, the probability of grass sickness in horses was modelled using conditional logistic regression techniques. Young animals were found to be at increased rick of grass sickness and females were less likely to become affected, as were animals that had a history of contact with previous cases of the disease. The probability of grass sickness was higher in animals that were on premises where grass sickness had previously occurred, particularly if this was recent. Animals were at particular risk of disease if they changed fields within the previous 2 weeks; the risk thereafter reduced with time. The disease had a seasonal pattern, with a peak from April to June. More than 95% of cases had access to grazing, and 66% occurred after 2 week periods of predominantly dry weather.

Dysautonomia in dogs: a retrospective study

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 (0.0375 mg/kg s.c.) bethanechol test and pharmacological testing with phenylephrine and epinephrine also demonstrated cholinergic and adrenergic receptor function in 4 dogs. All dogs died or were euthanized as a results of autonomic dysfunction. Neuronal depletion, with associated gliosis and minimal inflammation were noted histologically in the autonomic ganglia of each dog. The pelvic, ciliary, celiac, cranial cervical, and cranial and caudal mesenteric ganglia were affected in all dogs. The cause of autonomic failure in these dogs was not determined.

Feline dysautonomia (the Key-Gaskell syndrome): an ultra structural study of autonomic ganglia and nerves

Recently a feline dysautonomia of unknown aetiology, the Key-Gaskell syndrome, has caused widespread morbidity in the UK. This report describes the ultrastructural appearances of the autonomic ganglia and axons of the sympathetic chain in this condition. Nuclei of affected neurones were eccentric and abnormally crenated. Nucleolar abnormalities such as increased electron density (due to loss of the intranucleolar vacuoles), nucleolar segregation and ring nucleoli were observed in a proportion of neurones. There was marked loss of ribosomes, both bound and unbound, and cisternae of the rough endoplasmic reticulum were distended with a floccular electron dense material. Numerous smooth-walled cisternae were also present and complex stacks of smooth semi-parallel membranes were observed, probably derived from the smooth endoplasmic reticulum or Golgi apparatus. No normal Golgi formations were seen. Frequent autophagic vacuoles and membranous dense bodies were present in some cells. Many unmyelinated fibres in the sympathetic chain were swollen and contained vesiculo-tubular profiles, disordered neurotubules and filaments and various degenerating membranous organelles. Myelinated fibres within the sympathetic chain were also degenerating. These studies indicate that the organelles involved with protein biosynthesis are severely affected by the disease.