Hirayama Disease: Case Report / Doença de Hirayama: Relato de caso

Abstract A 26-year-old previously healthy patient who, at the age of 18 years, began progressive loss of distal strength, rest tremor, and muscle atrophy in the left upper limb. Upon examination, the patient presented moderate distal atrophy, degree 4 in muscular strength, and minipolymioclonus. Electromyoneurography revealed (EMNG) chronic preganglionic bilateral involvement of bilateral C7/C8/T1, worse on the left, with signs of active C8/T1 denervation. A cervical spine magnetic resonance imaging (MRI) scan showed spondylodiscal degenerative changes with central protrusions in C4-C5, C6-C7, and right central in C5-C6, which touched the dural sac. The anteroposterior diameter of the medulla in neutral position, in the C5-C6 plane, was of 5.1 mm. There was a reduction of the spinal cord caliber to 4.0 mm after the dynamic maneuver of forced flexion of the spine, as well as signal increase in the anterior horns. The clinical findings and those of the complementary tests were compatible with Hirayama disease (HD), a rare benign motor neuron disease that affects cervical spinal segments and is most prevalent in men, with onset in the early 20s. Unilateral and slowly progressive weakness is typical, but self-limited. Sensory disturbances, and autonomic and upper motor neuron signals are rare. Management is usually conservative, with the use of a soft cervical collar. Although rare, HD should be considered in young patients with focal asymmetric atrophy in the upper limbs. The early diagnosis of HD depends on the degree of suspicion, as well as on the cooperation and communication among the various specialties involved in the investigation.

Resumo Paciente de 26 anos, previamente hígido, que, aos 18 anos, iniciou perda progressiva de força distal, tremor de repouso, e atrofia muscular no membro superior esquerdo. Ao exame, apresentou atrofia moderada, distal, força muscular de grau 4, e minipolimioclonus. A eletroneuromiografia (ENMG) revelou comprometimento pré-ganglionar crônico de C7/C8/T1 bilateral pior à esquerda, com sinais de desnervação ativa em C8/T1. A ressonância magnética (RM) de coluna cervical mostrou alterações degenerativas espondilodiscais com protrusões centrais em C4-C5, C6-C7, e central direita em C5-C6, que tocavam o saco dural. O diâmetro anteroposterior da medula na posição neutra, no plano de C5-C6, era de 5,1 mm. Houve redução do calibre da medula para 4,0 mm após a manobra dinâmica de flexão forçada da coluna, e aumento de sinal nos cornos anteriores. Os achados clínicos e os dos exames complementares eram compatíveis com doença de Hirayama (DH), uma doença benigna rara dos neurônios motores, que afeta os segmentos espinhais cervicais e é mais prevalente em homens e de início próximo aos 20 anos. É típica a fraqueza unilateral e lentamente progressiva, porém autolimitada. Perturbações sensoriais, sinais autonômicos e do neurônio motor superior são raras. O manejo geralmente é conservador, com uso de colar cervical macio. Apesar de rara, a DH deve ser considerada em pacientes jovens que apresentam atrofias assimétricas focais de membros superiores. O diagnóstico precoce de DH depende do grau de suspeição, e da cooperação e comunicação entre as diversas especialidades envolvidas na investigação.

Analysis of electromyography and imaging characteristics of 5 cases of Hirayama disease / 中风与神经疾病杂志

@#Discuss the electromyography and imaging characteristics of Hirayama disease，and improve clinicians’ awareness of the disease. Methods A retrospective analysis of clinical data of five cases of Hirayama disease patients in our hospital，analyze its clinical manifestations，EMG and imaging features. Results 5 patients were male，age 18 to 28 years old，（3 cases） unilateral，bilateral involvement in two cases of asymmetry. Five patients showed the hand and forearm muscle weakness with atrophy，forearm ramp-like changes，with cold paralysis. Motor nerve conduction delay mainly ulnar nerve terminal during latent，median nerve，ulnar nerve compound muscle action potential （the CMAP） amplitude decreased，no motor nerve conduction block；sensory nerve conduction were normal. Needle electrode EMG neurogenic damage，abnormal muscle mainly in the C7-T1 segment dominated area. MRI in the neutral position of the cervical spine in 5 patients showed that the physiological curvature was straightened or the spinal cord was slightly thinned；2 cases showed LOA phenomenon in the cross section；5 cases showed different degrees of compression of the cervical spinal cord forward and the epidural space signal shadow in the flexion position，enhanced scanning Abnormal enhancement in the epidural space can be seen. Conclusion According to the clinical manifestations of Hirayama disease combined with its characteristic electromyography and MRI features，early diagnosis of Hirayama disease can be made.

Bilateral Hirayama Disease: A Case Report

Hirayama disease is a rare restricted form of motor neuron disease. It commonly affects young males. Patients typically presentwith the insidious onset of unilateral weakness and atrophy of the hand muscles that often progresses to the forearm. In somecases, the syndrome is bilateral but often asymmetrical. Of note, the brachioradialis muscle is usually spared. The syndromeaffects C7–C8–T1 muscles with sparing of the C5–6 muscles. We report a case of a 25-year-old male who presented with 2years of history of progressive wasting and weakness of muscles of bilateral hands and forearms. Based on clinical features,electrodiagnostic studies and dynamic magnetic resonance imaging cervical spine diagnosis of Hirayama disease were made.The patient was treated conservatively with a cervical collar. Over a period of 8 months follow-up, no progression was seen.

Two Cases of Hirayama Disease in a Pediatric Clinic / 대한소아신경학회지

We report two pediatric cases with Hirayama disease—a 16-year-old boy with a left wrist drop and a 14-year-old-boy with weakness and muscle atrophy of right hand. Motor nerve conduction study revealed decreased motor nerve action potential amplitudes in the ulnar nerve and radial nerve of the affected hands. The former patient showed normal magnetic resonance imaging (MRI) of the cervical spine, but the latter showed mild, asymmetric thinning of the anterior spinal cord at levels C5 to C7. Following active rehabilitation and avoidance of neck flexion, no further progression of neurological findings was noticed. These clinical findings were typical of Hirayama disease. We show that timely and accurate diagnosis for Hirayama disease is possible with awareness of disease history, careful physical examination, and the use of neurophysiological studies and MRI studies.

Resonancia magnética de columna cervical con secuencia en flexión para el diagnóstico de la enfermedad de Hirayama / Magnetic resonance of the cervical spine with sequence in flexion for the diagnosis of Hirayama disease

La enfermedad de Hirayama o atrofia muscular espinal juvenil no progresiva de las extremidades superiores es una clase de mielopatía relacionada con la flexión del cuello. Afecta principalmente a hombres jóvenes (entre 15 y 25 años) y se caracteriza por una debilidad muscular asimétrica y unilateral de miembros superiores con atrofia. Suele presentarse de manera insidiosa, con curso progresivo y autolimitado a los 3-4 años del inicio del cuadro. Se cree que es producida por trastornos isquémicos en la microcirculación de las astas anteriores del segmento medular cervical entre C8 y T1 por la compresión en el segmento medular anterior debido al desplazamiento anterior de la duramadre al flexionar el cuello. Si bien existen varias teorías sobre la causa de este deslizamiento, la más aceptada se relaciona con la falta de crecimiento de la duramadre con respecto a la columna durante la pubertad. Esto provocaría un aumento de la tensión de la dura posteriory, como consecuencia, el desplazamiento anterior durante la flexión. Dado su excelente contraste tisular y la posibilidad de realizar adquisiciones en distintos planos, la resonancia magnética es el estudio de elección. Las imágenes deben ser obtenidas en posición neutra y en flexión cervical máxima para poner de manifiesto el desplazamiento de la dura, con el consiguiente aumento de la sensibilidad y especificidad de la prueba. Así, se logra mayor confianza en el diagnóstico y menor cantidad de falsos positivos, en comparación con la posición neutra como única adquisición.

Hirayama disease is a type of myelopathy related to neck flexion. It affects young male adults between 15 and 25 years, and is characterised by unilateral and asymmetric upper limb muscle weakness with atrophy. It usually presents insidiously, with a progressive course and self-limits in 3-4 years. It is believed that it could be produced by ischaemic disorders in the microcirculation of the anterior horns of the cervical spine segment C8 and T1 due to anterior displacement of the dura. There are several theories for the cause of this displacement, with the most accepted being the relationship between the lack of growth of the dura mater and the spine during puberty. This increases the tension of the posterior dura mater and consequently the anterior displacement during flexion. Due to its excellent tissue contrast and the possibility of acquisitions in different planes, magnetic resonance imaging is the study of choice. Images must be obtained in both neutral and cervical flexion to highlight the displacement of the dura mater. This increases the sensitivity and specificity of the test, giving greater confidence in the diagnosis, and reducing false positives compared to neutral as a single acquisition.

The imageological advances in Hirayama disease / 复旦学报（医学版）

Hirayama disease is benign and self-limited,characterized by atrophy of unilateral upper extremity.Misdiagnosis was common due to the restriction of diagnostic techniques in the past.In recent years,Hirayama disease is familiar to us because of the rapid development of electromyography and imageological examinations.X-ray and CT scan play an important role in evaluations on cervical curvature,segmental stability,degeneration of facet joints and posterior longitudinal ligament.Loss of attachment in neutral cervical MRI and anterior shift of dura mater in flexion cervical MRI are the most important signs.This review summarizes the imageological examinations and characteristic signs of Hirayama disease in detail,together with a brief introduction to clinical manifestations and electromyography features.

Midterm clinical outcomes and radiological results of surgical treatment for Hirayama disease / 北京大学学报(医学版)

Objective:To assess the midterm clinical and radiological outcomes of internal fixation and fusion for the treatment of Hirayama disease and to evaluate the clinical significance and value of this procedure.Methods:In the study,36 patients were treated with anterior cervical internal fixation and fusion.The clinical outcomes including muscle strength and atrophy were recorded.The radiological outcomes including range of motion of cervical spine and the cross-sectional area of spinal cord at each level on MRI scan were measured before and at 3 month,1 year and 2 years follow-up time points after surgery.Results:(1) Clinical outcomes:all the patients showed no further progression of symptoms except one patient with mild progression of muscular weakness and atrophy.As the time passed by,the ratio of the patients with muscle strength and atrophy improvement increased.There were 26.5 ％ of patients in 3 months,36.0％ in 1 year and 85.7％ in 2 years who experienced muscle strength improvement.8.8％ of patients in 3 months,24.0％ in 1 year and 35.8％ in 2 years felt muscle atrophy improvement.And 12 of the 14 patients showed improved muscle strength and atrophy at the end of 2 years period follow-up.(2) Radiological outcomes:the range of motion (ROM) of C2-C7 was significantly decreased after the operation.The ROM of preoperation was 62.25° ±2.10° and that of 2 years postoperation was 13.67° ± 7.51°(P ＜ 0.01).The spinal cord was of no compression on flexion MRI.The cross-section area of spinal cord on MRI was significantly increased only at C6 level (P ＜0.05) at the end of three months follow-up.The level of increased cross-section area rose to C4-C5-C6 levels (P ＜0.01) in 1 year and to C4-C5-C6-C7 levels at the end of 2 years follow-up P ＜ 0.05).The cross-section area increased 15.60％ at C4,19.08％ at C5,21.60％ at C6 and 23.91％ at C7 with significant difference (P ＜0.05) 2 years after the operation.Conclusion:Anterior cervical internal fixation and fusion is an effective surgical treatment for Hirayama disease and may provide preferable midterm clinical and radiological outcomes.This procedure has clinical significance and value in terms of control of the progression and outcome of this disease.

Clinical Experiences of Uncommon Motor Neuron Disease: Hirayama Disease

Hirayama disease, juvenile muscular atrophy of the distal upper limb, is a rare disease predominantly affecting the anterior horn cells of the cervical spinal cord in young men. This cervical myelopathy is associated with neck flexion. It should be suspected in young male patients with a chronic history of weakness and atrophy involving the upper extremities followed by clinical stability in few years. Herein, we report 2 cases of Hirayama disease on emphasis of diagnostic approach and describe the pathognomonic findings at flexion magnetic resonance imaging.

Value of natural position of cervical vertebra using MRI in diagnosis of Hirayama disease / 实用放射学杂志

Objective To analyze the MRI features of Hirayama disease(HD)with cervical natural position and its diagnostic val-ue.Methods The natural position of cervical vertebra with MRI examination was used in 1 5 patients and 40 normal people.The spe-cificity and sensitivity of MRI features were analyzed and the ratio of cervical sagittal diameter/cervical transverse diameter (CSD/CTD)of the lower cervical cord was measured.Results CSD/CTD of the patients and control group had a significant difference (t=7.99,P =0.00).The sensitivity of LOA was 86.7%,and its specificity was 88.4%.The sensitivity of atrophy of the lower cervical cord was 80.0%,and its specificity was 79.5%.The sensitivity of the cervical spine curvature abnormalities was 40.0%,and its spe-cificity was 65.2%.The sensitivity of abnormal signal in the spinal cord was 46.7%,and its specificity was 87.5%.The sensitivity of abnormal signal in the epidural outer cavity was 20.0%,and its specificity was 96.8%.Conclusion MRI features of lower cervical cord in combination with clinical symptoms and signs can be helpful for the accurate diagnosis of HD.

Hirayama Disease with Proximal Involvement

Hirayama disease is a slowly progressing benign motor neuron disease that affects the distal upper limb. A 29-year-old man visited the hospital with a 1-year history of weakened left proximal upper limb. He was diagnosed with Hirayama disease 9 years ago, while there was no further progression of the muscle weakness afterward. Atrophy and weakness was detected in proximal upper limb muscles. Magnetic resonance imaging and somatosensory evoked potentials were normal. Needle electromyography showed abnormal findings in proximal upper limb muscles. Our patient had Hirayama disease involving the proximal portion through secondary progression. Clinical manifestation and accurate electromyography may be useful for diagnosis. Rare cases with progression patterns as described here are helpful and have clinical meaning for clinicians.