The present report deals with an unique case of
myokymia-
hyperhidrosis syndrome. A 46-year-old man developed generalized relatively slow, undulating movement of the muscles, excessive sweating,
muscle cramps and easy fatigability since three years ago. On admission, he had
generalized myokymia,
abnormal movements consisting of slow, undulating and worm-like muscular contractions. There was no
muscle atrophy or weakness, or sensory deficits. Deep tendon reflexes were diminished and no Babinski sign or other pathological reflexes were present. Muscle tone was in normal range. Neither
fasciculation nor
myotonia was found. Laboratory examinations revealed elevation of BMR with normal thyroid function. The value of anti-
Ach receptor antibody was below 0.6nmol/l. EMG recordings showed (1) continuous spontaneous repetitive discharges of NMU at a frequency of 30-50Hz, with duration of 1-2 seconds and amplitude of about 1 mV, were demonstrated at rest and the findings were consistent with
myokymia, (2) waxing phenomenon was observed on repetitive peripheral nerve stimuli, which didn't improve by the tension test, and (3) high amplitude, long duration and polyphasic NMU, a sign of
denervation, were observed on voluntary contraction. Muscle biopsy specimens from the left quadriceps showed a number of internal nuclei. On electron microscopy, clustered mitochondria and filamentous bodies were very often found in subsarcolemma. From these observations, damage to peripheral nerves, neuromuscular junctions and muscles may be responsible for the
generalized myokymia in our patient.