Myotonia, the continued active contraction of a muscle accompanied by electrical after-discharge activity in the electromyogram (EMG), is a characteristic inherited disorder. Acquired instances of myotonia rarely have been reported—most recently as a complication of diazacholesterol therapy.1 Most other instances of acquired clinical myotonia lack typical electrical discharges. This report describes a man with typical clinical and electrical myotonia associated with a small cell carcinoma of the lung.
Report of a Case.—
A 59-year-old man had a six-week history of muscle stiffness. No family member had a history of myotonia, and the patient had no prior history of stiffness of the limbs. For two weeks prior to admission he had received prednisone and phenylbutazone but had otherwise taken no drugs. He had noted increasing fatigue and weight loss for two months.Examination showed no weakness, wasting, or hypertrophy of skeletal muscle. A severe stiffness of his gait improved when
Humphrey JG, Hill ME, Gordon AS, Kalow W. Myotonia Associated With Small Cell Carcinoma of the Lung. Arch Neurol. 1976;33(5):375–377. doi:10.1001/archneur.1976.00500050061023
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