Myasthenia gravis canine: A differential diagnosis for infectious diseases of origin neurological

Abstract

Myasthenia gravis (MG) is a neuromuscular disorder caused by a reduction in the number of functional nicotinic acetylcholine receptors in the postsynaptic membrane. Some infectious neurological diseases can mimic this situation. The study describes a case of MG in dogs, showing the conduct in diagnosis and therapy, in addition to providing the awareness to major infectious diseases of neurological repercussions that may have similar symptoms. A canine, male, eight months old without a definite breed, had ataxia history and vocalization changes. On physical examination, the patient presented ataxia, paresis and muscle atrophy of the limbs, with flaccid tetraparesis. The animal was conscious, and with his tail movement. Serological tests were performed for the detection of toxoplasmosis and neosporosis and both showed up negative. Due to the exclusion of possible infectious presumptive diagnosis, it was established the clinical suspicion of MG acquired. It was performed intravenous infusion of anticholinesterase (neostigmine), 20 ug.kg-1. After four minutes, there was clinical improvement and the dog returned to walking, confirming thus the therapeutic and definitive diagnosis of MG acquired. Then, the recommended outpatient treatment was equivalent to the administration of pyridostigmine bromide, 2 mg. kg-1, orally, every eight hours until new recommendations. It is essential to consider MG in differential diagnosis of canine infectious neuropathies. Once established the correct diagnosis and a treatment protocol, there will be a positive impact on prognosis.