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

Management of dynamic cervical kyphosis with dorsal epidural lipomatosis: a Hirayama disease variant? Illustrative case

BACKGROUND

Hirayama disease, a cervical myelopathy characterized most commonly by a self-limiting atrophic weakness of the upper extremities, is a rare entity, scarcely reported in the literature. Diagnosis is made by spinal magnetic resonance imaging (MRI), which typically shows loss of normal cervical lordosis, anterior displacement of the cord during flexion, and a large epidural cervical fat pad. Treatment options include observation or cervical immobilization by collar or surgical decompression and fusion.

OBSERVATIONS

Here, the authors report an unusual case of a Hirayama-like disease in a young White male athlete who presented with rapidly progressive paresthesia in all 4 extremities and no weakness. Imaging showed characteristic findings of Hirayama disease as well as worsened cervical kyphosis and spinal cord compression in cervical neck extension, which has not previously been reported. Two-level anterior cervical discectomy and fusion and posterior spinal fusion improved both cervical kyphosis on extension and symptoms.

LESSONS

Given the disease's self-limiting nature, and a lack of current reporting, there remains no consensus on how to manage these patients. Such findings presented here demonstrate the potentially heterogeneous MRI findings that can be observed in Hirayama disease and emphasize the utility of aggressive surgical management in young, active patients whereby a cervical collar may not be tolerated.

Efficacy of Anterior Cervical Discectomy and Fusion for Female Patients with Hirayama Disease

OBJECTIVE

To compare the preoperative and postoperative hand function and radiographic parameters in female patients with Hirayama disease (HD).

METHODS

Consecutive female patients with HD undergoing anterior cervical discectomy and fusion were followed up. The postoperative hand functional data were obtained from the last follow-up, whereas the postoperative radiographic data were obtained from the examinations in 3- or 6-month follow-up after surgical treatments. The preoperative and postoperative data of hand functional and radiographic assessments were collected and compared between them. Logistic regression analysis was used to clear potential risk factors for surgical treatment.

RESULTS

In all, 15 female patients with HD were included in the follow-up study over 9 years. Significant differences were found in total scores (P < 0.001) and all 6 dimensions, including function (P = 0.003), activities of daily life (P = 0.002), work (P = 0.003), satisfaction (P = 0.002), appearance (P = 0.005), and HD-specific hand symptoms (P = 0.001) in hand functional assessment. The comparison of C2-C7 Cobb angle was statistically different (P = 0.042) in radiographic assessments. The course of illness was of marginal significance (P = 0.065) with curative effect of surgical treatment in logistic regression analysis.

CONCLUSIONS

Anterior cervical discectomy and fusion is an effective way to treat female patients with HD, and the course of illness may be correlated with the efficacy of surgery. For some female patients with HD with a clear diagnosis, early surgical treatment is worthy of clinical consideration.

Do patients with Hirayama disease require surgical treatment? A review of the literature

The main clinic characteristic of Hirayama disease (HD) is atrophy of the distal muscles in the upper limbs. Recently, an increasing number of HD cases have been reported. Many HD patients have persistently progressive symptoms and conservative treatments failed. This article aims to review the current status of the field and summarizes the main surgical treatment options for patients with HD. A comprehensive search of the PubMed and the Web of Science databases was conducted from their inception to September 15th, 2022. Search terms included "juvenile muscular atrophy of upper extremity", "Hirayama disease" and "surgery". A total of 169 relevant publications were identified and 29 articles were finally reviewed. Current surgical treatments for HD are either anterior cervical surgery or posterior cervical surgery. The two approaches can effectively stop the disease. However, no studies have compared the advantages and limitations of the two surgical methods. The previous view that HD can be improved with conservative treatment has been challenged. In many studies, surgical treatment has been shown to improve the hand function in patients with HD. However, there is still controversy about the methods of anterior and posterior cervical surgery. Future research could focus on exploring the advantages and limitations of different surgeries.

The clinical characteristics of Hirayama disease in females

INTRODUCTION

To characterize Hirayama disease in female patients, and increase awareness among clinicians regarding the specifics of this disease.

METHODS

Baseline data, clinical manifestations, characteristics of cervical-flexion magnetic resonance imaging, and electromyography were collected and compared among females and males with Hirayama disease. In addition, the literature on Hirayama disease in females up to October, 2021 was searched in PubMed and the relevant data were compared with the data from our study.

RESULTS

Twenty female and 40 male patients were included in this study. The average ages of onset and menarche were 14.65 and 12.75 years old. All patients suffered from muscular weakness and atrophy of the upper limb(s), with flattening and/or atrophy of the lower cervical spinal cords in cervical-flexion magnetic resonance imaging, and neurogenic patterns in the atrophic muscles as determined using electromyography. The age of onset in females was about 2 years later than the age of menarche, and the age of onset in females was 2 years earlier than that in males. There were no obvious differences in clinical presentation between males and females.

DISCUSSION

Although females presented with Hirayama disease two years earlier than males, no other clinical differences were observed. Hirayama disease is likely associated with growth and development in puberty, and early identification, regardless of whether patients are male or female, is critical to optimizing prognosis.

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

Background

Magnetic resonance imaging (MRI) features are typical findings in Hirayama disease (HD) and are useful diagnostic entities but may not be present in all patients.

Case presentation

We present the case of a 22-year-old Nepalese man who presented with insidious onset of weakness of his right upper limb of more than 5 years duration. His weakness was progressive for the first 3 years, and then remained static. On examination, weakness of the interossei, thenar, hypothenar, flexor, and extensor muscles were present in his right upper limb, power was normal in his left upper and bilateral lower limbs. Minipolymyoclonus was present in both upper limbs, less prominent on the left side. Electrophysiological findings showed motor axonal neuropathy in his right upper limb, neurogenic discharges and fibrillations, and fasciculations in both upper limbs. Contrast magnetic resonance imaging (MRI) of his cervical spine in flexion was normal. Our patient was diagnosed with HD based on clinical and electrophysiological findings. Our patient was advised to use a cervical collar and regular physiotherapy and was found to have subjective benefit.

Conclusion

A normal cervical MRI does not rule out HD and the diagnosis can also be made based on clinical and electrophysiological studies. Progressive distal upper limb weakness or tremor in young patients should be evaluated for HD, because early diagnosis and intervention might halt the progression.