Nationwide survey of juvenile muscular atrophy of distal upper extremity (Hirayama disease) in Japan

Abstract

Juvenile muscular atrophy of the distal upper extremity (JMADUE, Hirayama disease) was first reported in 1959 as 'juvenile muscular atrophy of unilateral upper extremity'. Since then, similar patients in their teens or 20s have been described, under a variety of names, not only in Japan, but also in other Asian countries, as well as Europe and North America. Biomechanical abnormalities associated with JMADUE have recently been reported through various imaging examinations, proposing its disease mechanism. Since JMADUE differs from motor neuron disease, or spinal muscular atrophy, this disease entity should be more widely recognized, and early detection and effective treatments should be considered. We report an epidemiological study in Japan. Two nationwide questionnaire-based surveys, conducted in Japan from 1996 to 1998, identified 333 cases. The numbers of patients per year, distribution of ages at onset, mode of onset, time lapse between onset and quiescence, neurological signs and symptoms, imaging findings, and the effects of conservative treatments were analyzed. The peak age was 15 to 17 years, with a marked male preponderance, usually a slow onset and progression, and quiescence six or fewer years after onset. There was a predominantly unilateral hand and forearm involvement with 'cold paresis'. The imaging findings are described.

Cervical spondylotic amyotrophy

“…Tashiro et al [43] described the clinical requirements for the diagnosis of Hirayama's disease. One of the diagnostic criteria is distal dominant muscle weakness and atrophy in the forearm and hand, which means the peak in the flexion position is generally at the C6 level.…”

Late‐onset monomelic amyotrophy in a Caucasian woman

“…About 70% of patients progress for less than 3 years, and in close to 95% the illness attains a stationary phase by the end of 5 years. 12 Progression as long as 8 years has been reported but we are unaware of cases with the highly unusual, progressive course of 19 years that occurred in our patient. 1 This temporal profile does resemble the extremely rare O'Sullivan-McLeod syndrome, 9 originally described in 1978.…”

“…These include brachial monomelic amyotrophy, benign focal atrophy, benign focal amyotrophy, Sobue's disease, and juvenile segmental muscular atrophy. Tashiro et al 12 recently outlined requirements for the diagnosis (Table 1).…”

“…5,7 In some patients, MRI studies have documented asymmetric atrophy of the distal cervical spinal cord with epidural venous dilatation. 7,6,12 Japanese investigators have suggested that monomelic amyotrophy may be due to microvascular changes following chronic trauma to the spinal cord during flexion and extension of the neck, especially during adolescence when there is rapid growth. 7 A 10-year-old Swiss girl has been reported who presented with a monomelic atrophy and concomitantly had a very peculiar parasomnia.…”

“…12 However, the absence of corticospinal tract involvement is against an ischemic hypothesis, as this tract, found at the border zone of the anterior spinal artery distribution, should also be affected. 12 Furthermore, pathalogic studies demonstrated loss of motor neurons with gliosis and accumulation of lipofuscin with occasional basophilic inclusions in the remaining neurons, but no signs of ischemia or vascular abnormalities in the autopsy findings of one patient.…”