| The acquired form of myasthenia gravis occurs in dogs and rarely in goats and cats. Affected animals produce autoantibodies to acetylcholine receptors, which bind to the receptor and reduce acetylcholine. The clinical manifestations mimic those produced by curare. Extreme generalized muscle weakness, accentuated by mild exercise, is common. Megaesophagus is a frequent primary or accompanying complaint in dogs. Thymomas are often associated with myasthenia gravis in humans, but this
is uncommon in other animals. Administration of a short-acting anticholinesterase (edrophonium chloride) produces a dramatic increase in muscle strength. Treatment is with a long-acting anticholinesterase. Chronic immunosuppressive drug therapy for this disease is logical and should be investigated. Autoantibodies to the acetylcholine receptors can be detected in the serum of affected animals by an indirect immunohistopathologic analysis using normal muscle as a substrate. |
