Clinical and radiological profile of Hirayama disease: A flexion myelopathy due to tight cervical dural canal amenable to collar therapy

Abstract

Background:Hirayama disease (HD) is benign focal amyotrophy of the distal upper limbs, often misdiagnosed as motor neuron disease. Routine magnetic resonance imaging (MRI) is often reported normal.Objective:To study the clinicoradiological profile of hand wasting in young males.Materials and Methods:Patients presenting with insidious-onset hand wasting from March 2008 to May 2011 were evaluated electrophysiologically. Cervical MRI in neutral position was done in 11 patients and flexion contrast imaging was done in 10 patients.Results:All patients were males less than 25 years of age, with median age 23 years, except one patient who was 50 years old. Duration of illness was 3 months to 3 years. All (100%) had oblique amyotrophy, four (36%) cold paresis, 10 (91%) minipolymyoclonus and three (27%) had fasciculations. Regional reflexes were variably absent. Two patients (18%) had brisk reflexes of lower limbs with flexor plantars. Electromyography (EMG) showed chronic denervation in the C7-T1 myotomes. Neutral position MRI showed loss of cervical lordosis in 10/11 (91%), localized lower cervical cord atrophy in 9/11 (82%), asymmetric cord flattening in 11/11 (100%) and intramedullary hyperintensity in 2/11 (18%); flexion study showed loss of dural attachment, anterior displacement of dorsal dura, epidural flow voids in 9/10 (90%) and enhancing epidural crescent in 10/10 (100%). Clinical profile, imaging and electrophysiological findings of the patient aged 50 years will be described in detail as presentation at this age is exceptional. Collar therapy slowed progression in most cases.Conclusion:Clinical features of HD corroborated well with electrophysiological diagnosis of anterior horn cell disease of lower cervical cord. While dynamic contrast MRI is characteristic, routine studies have a high predictive value for diagnosis. Prompt diagnosis is important to institute early collar therapy.

Hirayama Disease: Imaging Profile of Three Cases Emphasizing the Role of Flexion MRI

“…It is a benign motor neuron disorder that typically affects the distal upper extremity from the C7 to T1 myotomes although C4 to C6 myotomes can also be involved [2]. The pattern of involvement is unilateral in most cases although bilateral asymmetric involvement is not uncommon.…”

Hirayama Disease Involving Bilateral Distal Upper Limbs of a Student: A Case Report

“…[2,3] It seems to be caused by dynamic compression of the lower cervical cord resulting from sustained or repeated neck flexion. [2,4,5] Its relatively benign course and characteristic appearance of oblique amyotrophy differentiate it from motor neuron disease. [2,4] As the Dynamic MRI (Neutral and flexed) of cervical spine is the mainstay for confirming clinical diagnosis, it is frequently underdiagnosed.…”

A severe case of Hirayama disease successfully treated by anterior cervical fusion

“…Neutral and flexion cervical MRI shows asymmetrical atrophy of the spinal cord, forward displacement of the posterior dural sac with neck flexion, and thus, secondary cord compression against the posterior wall of the vertebral body. 6,15,16,21,27,30 Since neck flexion was recognized as a possible cause of the disease, several therapies have proved their utility, shortening the progression period and even improving the patient's strength. Wearing a cervical collar is the most common conservative therapy.…”

“…Over the past 50 years, with the advent of MRI, several researchers have established this illness as a different entity from the motor neuron diseases. [6][7][8][9][10]13,17,25,26 It has been characterized not as a primary disease of motor neurons, but as a myelopathy secondary to spinal cord compression during cervical flexion.The clinical features of Hirayama disease are: 1) asymmetrical weakness of the distal upper extremities, with atrophy of the thenar and hypothenar eminence and relative sparing of the brachioradialis muscle (oblique amyotrophy); 2) cold paresis (worsening of the weakness and distal tremor with cold); 3) lack of sensory, autonomic, or cranial nerve signs or symptoms; 4) insidious onset at the second to third decades of life (15-25 years), predominantly in males, with slow worsening over a variable period of time (mean 5 years) 31 and subsequent spontaneous arrest of progression; and 5) usually sporadic occurrence (although familial cases have been reported). 1,3,14,23 Radiological findings are essential for the diagnosis of Hirayama disease.…”

“…Over the past 50 years, with the advent of MRI, several researchers have established this illness as a different entity from the motor neuron diseases. [6][7][8][9][10]13,17,25,26 It has been characterized not as a primary disease of motor neurons, but as a myelopathy secondary to spinal cord compression during cervical flexion.…”