[Sweating deficiency in myotonic dystrophy].

We evaluated local sweating function quantitatively in nine cases of myotonic dystrophy (MyD) aged 26 to 61 years (mean, 45.4 years) and 25 control subjects aged 24 to 71 years (mean, 50.1 years). MyD subjects were grouped into three clinical classes according to their severity (three mild cases; class 1, three moderate; class 2 and three severe; class 3). 10 mg of acetylcholine was injected intradermally on the dorsum of the foot. After stimulation the impressions of sweat droplets were obtained using vinyl silicon impression material and the number of sweat droplet impressions per square centimeter was counted and the diameter of each droplet was measured by an image processor using a microcomputer. The result showed statistically significant decrease in the number of sweat droplets in class 2 and 3 as compared with control group and class 1. The histogram of sweat droplet diameter disclosed tendency of progressive deficit in diameter in all three clinical classes of MyD. Various kinds of autonomic function test, besides sweat tests, and nerve conduction study done on class 2 and 3 failed to show any significant abnormalities. Skin biopsy study done on lower leg on four subjects of class 2 and 3 revealed atrophy of eccrine sweat glands. These results suggests that local sweating deficiency develops in MyD as the disease progresses and that this deficiency is caused by dysfunction of eccrine glands, and not of postganglionic autonomic nerves.(ABSTRACT TRUNCATED AT 250 WORDS)