Selected disorders of muscle and the neuromuscular junction.

A variety of disorders affect the muscles or the neuromuscular junction of dogs and cats, most often causing weakness, exercise intolerance, and muscular pain or atrophy. The myopathies are infectious, immune-mediated, inherited or acquired secondary to systemic disease. Acquired myasthenia gravis is a common disorder of the neuromuscular junction, which clinically resembles a myopathy. Reaching a specific diagnosis is essential to determine optimal therapy and prognosis for each of the commonly recognized disorders.