Dynamic Cervical MR Imaging Findings of Patients With Hirayama Disease in a Tertiary Care Hospital of North-East India

Abstract

BACKGROUND Juvenile muscular atrophy of the distal upper limb (Hirayama disease) is a rare disease, predominantly affecting the anterior horn cells of the cervical spinal cord in young men. Most studies of Hirayama disease have been conducted in Asia, particularly Japan. To characterise the MR imaging findings of patients of NorthEast India with HD, we reviewed neutral and flexion cervical MR imaging examinations performed for suspected patients with possible HD at tertiary care hospital in NorthEast India. MATERIALS AND METHODS We assessed the MR imaging examinations with clinical correlation in young males with weakness and hand muscle wasting retrospectively for LOA (Loss of Attachment) of the posterior dura to the spine, cervical spinal cord atrophy, spinal cord T2 hyperintensity, loss of cervical lordosis, anterior dural shift with flexion in patients from 2014 to 2017. These patients were also evaluated electrophysiologically. RESULTS Twenty-four patients met the criteria for HD. All were males of different ethnic background, predominantly in the persons engaged in lifting/ pulling heavy objects. Findings of HD were often present on neutral images, but the addition of flexion images increased diagnostic confidence. All patents were males less than 30 years of age. All (100%) had oblique amyotrophy, 9 (37.5%) had fasciculations and 6 (25%) had cold paresis. Electromyography (EMG) showed chronic denervation in C7-T1 myotomes. NCS (Nerve conduction study) showed reduced compound muscle action potential (CMAP) in median and ulnar compound muscle in nine patients. Neutral position MRI showed loss of cervical lordosis (100%), localised lower cervical cord atrophy (100%) and intramedullary hyperintensity (60%). Flexion study showed loss of dural attachment, anterior displacement of dorsal dura and epidural flow voids (90%) and enhancing epidural crescent in (90%). CONCLUSION Young males of NorthEast India with clinical HD corroborated well with electrophysiological diagnosis of anterior horn cells disease. While the findings often present on neutral and flexion MR images, as dynamic contrast MR imaging findings is characteristic should be performed. Prognosis of the disease progression runs benign course with early diagnosis and help in early treatment modalities.