Hirayama disease: analysis of cases in Russia

Area of Science:

• Neurology
• Clinical Neuroscience
• Rare Diseases

Background:

• Hirayama disease (HD) is a rare neurological disorder characterized by juvenile muscular atrophy of the upper extremities.
• It typically presents with a benign clinical course, but can be misdiagnosed as other neurological conditions.
• Early and accurate diagnosis is crucial due to differing prognoses and potential interventions.

Purpose of the Study:

• To present fourteen cases of Hirayama disease diagnosed at the Research Center of Neurology.
• To analyze clinical signs, diagnostic methods, and propose a new scale for assessing neurological disturbances in HD.
• To investigate correlations between HD severity, patient age, and disease duration.

Main Methods:

• Diagnosis confirmed using magnetic resonance imaging (MRI), electromyography (EMG), and nerve conduction studies (NCS).
• Transcranial magnetic stimulation (TMS) was employed to rule out upper motor neuron involvement in select cases.
• An original scale for neurological disturbances in HD was developed and applied.

Main Results:

• Clinical and electrophysiological findings (MRI, EMG) were consistent with previous literature.
• Hirayama disease severity was found to be independent of patient age and disease duration.
• Misdiagnosis as amyotrophic lateral sclerosis (ALS) and other neurological disorders occurred in some cases prior to accurate HD diagnosis.

Conclusions:

• The independence of HD severity from age and duration may be linked to individual anatomical variations in the cervical spine.
• Accurate diagnostic methods like MRI and EMG are vital for differentiating HD from other neuromuscular diseases.
• Prompt diagnosis of Hirayama disease is essential for appropriate management and to avoid confusion with conditions like ALS.