Hirayama disease (monomelic amyotrophy) clinically confused for carpal tunnel syndrome

Abstract

Hirayama disease (HD) is a rare motor neuron disorder that involves a single upper extremity. It is clinically characterized by weakness and atrophy of the muscles of the hand and forearm. This article presents a 19-year-old woman who visited the orthopedics outpatient clinic with weakness and atrophy in her right hand and was clinically diagnosed with advanced stage carpal tunnel syndrome and scheduled for surgical intervention; she was later diagnosed with HD by an electrophysiological study. As a result, it has been found that a careful electrophysiological study and neurological examination can be used to diagnose HD. In this way, advanced stage carpal tunnel syndrome will be ruled out and patients will be spared from an unnecessary surgical operation.

The diagnostic quandary of magnetic resonance imaging-negative Hirayama disease: a case report

“…If the flexion MRI is normal and if the index of suspicion is high, a serial flexion MRI of the cervical scan can be performed. However, in some cases, including ours, there were characteristic clinical features with a progression pattern, NCT/EMG findings, and negative MRI results despite serial MRI in the proper flexion angle [2,8]. Symptoms in patients with HD are due to the result of pathological changes in the anterior horns of the lower cervical cord, such as ischemia and necrosis.…”

“…Early intervention can minimize disease progression. Conservative treatments, such as the use of cervical braces to prevent cervical spine flexion, have been shown to reverse disease progression [4,8,9]. Surgical treatment is required only in selective cases, where progressive deterioration occurs despite conservative treatment and includes anterior cervical decompression surgery or duroplasty or reconstructions with tendon transfers [4].…”

Hirayama Disease in an Adolescent Male With Right Hand Weakness and Muscle Wasting

“…Hirayama disease, also known as monomelic amyotrophy 1 or juvenile muscular atrophy of the upper extremity, 2,3 is a rare neurologic condition that involves the inferior motor neurons 1 and commonly affects the C7 to T1 spinal nerves and their myotomes. 4 Hirayama first described this type of cervical myelopathy in 1959, stating that it was clinically differentiated from the other known types of motor neuron disease.…”

“…5 Characterized by insidious onset, 1,6,7 this disease, commonly associated with Asian descent, has a male predominance ranging from 7:1 4,6 to 20:1, 7,8 depending on the population, and is typically diagnosed during the second and third decades of life. 1,6,8,9 Although the exact pathophysiology is unknown, one theory is an imbalance between the growth of the vertebral column and that of the spinal canal contents, 7 a discrepancy that results in forward displacement of the posterior dural sac with neck flexion, 10 leading to compression and injury of the spinal cord with posterior damage to the anterior horn cells. 6 Hirayama disease commonly presents with unilateral or bilateral asymmetric weakness and muscle wasting of the C7 to T1 myotomes, with characteristic sparing of the brachioradialis muscle and without associated sensory loss.…”

The Role of Electrodiagnostic Studies in Carpal Tunnel Syndrome: Beyond Confirmation of Diagnosis

“…An example is the reported case of a girl with Hirayama disease who was clinically misdiagnosed as having advanced stage carpal tunnel syndrome and was to have surgical carpal tunnel release when electrodiagnostic studies were not performed. 6 Other median nerve pathologies, such as median nerve compression in the forearm, can masquerade as carpal tunnel syndrome because the 2 entities can hardly be distinguished clinically. Given these limitations, it seems that basing an invasive treatment (ie, surgical carpal tunnel release) on merely positive history and physical examination is of questionable merit.…”