Cardiovascular and sudomotor dysfunction in Hirayama disease.

Hirayama disease is a disease of young males causing atrophy of small muscles of the affected hand and forearm. Localized autonomic dysfunction of the affected upper limb such as cold skin and excessive sweating has been described in some patients. In this study, we looked for local as well as systemic involvement of autonomic nervous system in patients with Hirayama disease. Forty-four patients with a median duration of illness of 3 years were included in the study. Assessment of symptom profile and evaluation of autonomic nervous system were done at the time of enrolment. The mean age at presentation was 21.9 (10-32) years, with a delay in seeking medical attention of around 3 (1-11) years. Localized clinical autonomic dysfunction was present in 39 (88.6%) patients, while objective generalized autonomic dysfunction was present in 33 (75%) patients. Cold skin and excessive sweating showed good correlation with the presence of objective autonomic dysfunction (P < 0.05). In three patients, sympathetic skin response (SSR) could not be recorded in one of the four limbs. Compared to controls, the SSR results in patients with Hirayama disease showed increased latency (1.64 ± 0.21 vs. 1.57 ± 0.14, P 0.04) and decreased amplitude in upper limbs (0.65 ± 0.19 vs. 0.86 ± 0.40, P 0.01). Hirayama disease has both localized and systemic dysautonomia. Careful longitudinal evaluation during the progressive phase of the disease may help in diagnosing subtle systemic autonomic dysfunction.