Non familial juvenile distal spinal muscular atrophy of upper extremity

An Effort to Identify Genetic Determinants in Siblings With Wilson Disease Manifesting Striking Clinical Heterogeneity: An Exome Profiling Study of Two Indian Families

BACKGROUND

Wilson disease (WD) is a rare autosomal recessive disorder of copper metabolism caused due to mutations in the copper transporter ATP7B. There is often a striking variability of clinical manifestations among patients with ATP7B mutations, including in siblings. This phenomenon may be caused by individual differences in copper accumulation in hepatocytes and intolerance to copper toxicity as governed by genetic variations in copper metabolism genes acting as modifier loci to the disease.

OBJECTIVE

To elucidate the genetic basis of striking clinical heterogeneity among two siblings of two families with WD.

METHODS

The disease diagnosis and subsequent clinical examinations were performed by expert clinicians. The younger siblings in both families presented with early neurological manifestations at a younger age than their older siblings. Interestingly, only the younger siblings were reported to have had hepatic manifestations. Exome sequencing of all the four individuals was performed to understand their heterogeneous phenotypic outcomes.

RESULTS

Genetic screening revealed no difference in the ATP7B variant spectrum between the siblings of each family. However, the siblings of both the families were found to harbor mutually exclusive pathogenic variants in suspected modifier genes implicated in copper metabolism and/or other neurological and hepatic disorders having overlapping symptoms with WD, viz., CFTR, PPARG, ABCB11, ATP7A, CYP2D6, mTOR, TOR1A, and CP, which can potentially explain their differential clinical phenotypes.

CONCLUSION

Clinical heterogeneity between siblings with WD with the same ATP7B mutation profile may be attributed to the presence of different pathogenic variants in potential modifier genes.

Study of monomelic amyotrophy of the lower limbs in the territory of the Western Balkans: Case series

RATIONALE

Monomelic amyotrophy is a rare form of motor neuron disease in which the neurogenic atrophy is restricted to 1 limb, mostly the distal part of the arm. The disease most often occurs in Asia, especially in Japan and India, while in European countries, this disease is rarely recognized. Registration and publication of new cases of this disease aims to increase the awareness of clinicians about the existence of this disease in European countries, and with the aim of easier recognition and faster diagnosis of this essentially benign disorder.

PATIENT CONCERNS

Five patients with signs of atrophy of the muscles of 1 leg were examined at our Institution.

DIAGNOSES

The criteria for selecting patients were as follows: clinical evidence of wasting and weakness confined to the 1 lower limb; progressive course, or initial progression followed by stationary course; absence of any definite sensory loss or central nervous system involved; no evidence of compression lesion of the spinal cord.

INTERVENTIONS

The clinical characteristics of our patients were similar to those previously described in the literature. The characteristic clinical features were sporadic occurrence, predominance in males with an initially progressive course for 2 to 5 years followed by a stationary state. There was no family history of neuromuscular disease.

OUTCOMES

The electromyographic finding was consistent with a chronic neuropathic disorder. Magnetic resonance imaging of the lumbosacral spine excluded intraspinal pathologies and root compression in all cases.

LESSONS SUBSECTION

Monomelic amyotrophy of the lower limb is a rare disease that should be considered in cases of slow progressive unilateral amyotrophy of a single leg, especially in younger and middle-aged men, not only in Asia but also in the Western Balkans and Europe.

Hirayama disease with proximal upper limb involvement in an adolescent female: A case report

Introduction and importance

Hirayama disease is a rare benign motor neuron disorder that involves a single upper limb. It affects the lower cervical myotomes and presents clinically by muscle wasting and weakness.

Case presentation

We report the case of a 17-year-old female who presented with a four weeks history of progressive weakness of the left upper limb. The blood investigations and image reported unremarkable findings. Patient improved on physiotherapy.

Clinical discussion

Hirayama disease is rarely encountered in clinical settings and should be suspected in female patients presenting with unilateral or asymmetrical bilateral lower motor weakness of hands and forearms.

Conclusion

We present a rare condition in a 17-year-old female with a left upper extremity monomelic amyotrophy, a Hirayama disease.

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We report a case of Hirayama disease in a 17-year-old female who was managed conservatively by physiotherapy.

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Patient presented with left shoulder amyotrophy with a normal cervical CT scan and normal blood investigations.

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Conservative management still the management of choice in our setting in case of Hirayama disease.

Hirayama's Disease: A Rare Clinical Variant of Amyotrophic Lateral Sclerosis

Hirayama's disease is a rare clinical variant of amyotrophic lateral sclerosis where distal muscles are involved more compared to proximal muscles and vice-versa occurs only in 10% cases and so it is differentiated from O'Sullivan McLeod syndrome which involves only small muscles of single limb. Here, we present a case of Hirayama's disease where disease achieved a plateau after 3 years with no further progression. His electrophysiological studies, and clinical picture, and magnetic resonance imaging findings were consistent with a diagnosis of Hirayama's disease.

A Confirmed Case in the United Kingdom of Hirayama Disease in a Young White Male Presenting with Hand Weakness

BACKGROUND

We present the first reported case of Hirayama disease in the United Kingdom. A literature review of Hirayama disease in the Western literature shows that this case is unique in being the first in the United Kingdom, constituting one of only a few cases in Europe with supporting magnetic resonance imaging and reported treatment outcome.

CASE DESCRIPTION

Our patient was a young Caucasian male who presented with progressive bilateral hand weakness, had confirmatory magnetic resonance imaging findings of Hirayama disease, and experienced improvement of symptoms with cervical collar immobilization.

CONCLUSIONS

This case lends further evidence to the flexion-induced myelopathy theory of Hirayama disease and supports the findings of other studies in which avoidance of neck flexion and cervical immobilization helped to attenuate disease progression in this patient group.

Benign focal amyotrophy

Within lower motor neuron diseases, benign focal amyotrophy is a rare syndrome characterized by insidious neurogenic asymmetric atrophy restricted to upper or lower limbs with a good prognosis over time. Described under several terms, the nosology is probably heterogeneous. In juvenile distal upper-limbs forms, specific MRI signs with in particular a compression of the spinal cord by forward displacement of dura, lead to evoke a mechanical process. In other forms, occurring later in the life, affecting proximal part of upper limbs or lower limbs, the physiopathology is still unknown and a focal spinal muscular atrophy is suspected. In this review, we will discuss the clinical, electrophysiological and radiological features of each presentation.

Correlations of clinical, neuroimaging, and electrophysiological features in Hirayama disease

Hirayama disease (HD) is characterized by development of asymmetric forearm muscle atrophy during adolescence with or without focal cervical spinal cord atrophy. The purpose of this study is to assess the correlation of clinical symptoms, disease progression, and electrophysiological findings with cervical spine magnetic resonance imaging (MRI) findings.The medical records, cervical spine MRIs, and electrophysiological findings of 44 HD patients were retrospectively reviewed and analyzed.Denervation changes in any single C5 to C7 root-innervated muscle (deltoid, biceps, triceps, or extensor digitorum communis) occurred more frequently in the 25 patients with cord atrophy than the 19 patients without cord atrophy (88% vs 53%, P = 0.02). Onset age, duration of disease progression, neurological examinations, nerve conduction study, and electromyographic findings from individual muscles were similar between patient groups.Compared with HD patients without cord atrophy, HD patients with cord atrophy experience a more severe denervation change in C5 to C7 root-innervated muscles.

Monomelic amyotrophy with proximal upper limb involvement: a case report

BACKGROUND

Monomelic amyotrophy is an uncommon, benign, unilateral disorder of the lower motor neurons, affecting predominantly the hand and forearm muscles. Proximal involvement of the arm and shoulder muscles is an unusual presentation that has been rarely reported in the literature.

CASE PRESENTATION

A 28-year-old white man presented with insidious-onset, slowly progressive, unilateral weakness and atrophy of his left shoulder girdle and deltoid muscles. A neurological examination revealed weakness and atrophy in his left deltoid, infraspinatus and supraspinatus muscles. Electromyography demonstrated an active and chronic neurogenic pattern affecting his left C5 and C6 myotomes; magnetic resonance imaging of his cervical spine was normal. He did well with conservative treatment.

CONCLUSIONS

Upper limb proximal form of monomelic amyotrophy is a rare clinical entity with a wide differential diagnosis. Physicians, especially neurologists, should be familiar with this benign condition to avoid inappropriately labeling patients as having amyotrophic lateral sclerosis and other disorders with less favorable outcomes.

Sporadic lower motor neuron disease with a snake eyes appearance on the cervical anterior horns by MRI

OBJECTIVE

Lower motor neuron disease (LMND) is the term generally used to describe diseases in which only lower motor neuron signs are detected. A snake eyes appearance on magnetic resonance imaging (MRI) is associated with a wide spectrum of neurological conditions including LMND. The author reports on three unique LMND patients with upper limb muscle weakness and atrophy who show a snake eyes appearance by MRI.

PATIENTS AND METHODS

The patients were aged 18, 40 and 52 years, respectively, at the onset of the disease and had a longstanding clinical course (more than 10 years for two patients and 8 years for one patient). They were followed up for more than 6 years.

RESULTS

Clinical manifestations were characterized by (1) longstanding slow progression or delayed spontaneous arrest of asymmetric lower motor neuron signs localized exclusively in the upper extremities with unilateral predominance and distal or proximal preponderance; (2) the absence of upper motor neuron signs, bulbar signs, sensory disturbances and respiratory involvement; (3) a snake eyes appearance on the anterior horns of the cervical cord over more than 3 vertebrae by axial T2-weighted MRI and a longitudinal linear-shaped T2-signal hyperintensity by sagittal MRI; (4) neurogenic change with fasciculation and denervation potentials (fibrillation and a positive sharp wave) confined to the affected muscles by needle electromyogram; and (5) normal cerebrospinal fluid and a normal creatine kinase level. These cases did not fall into any existing category of LMND, such as progressive muscular atrophy, flail arm syndrome or Hirayama disease.

CONCLUSIONS

These patients should be classified as sporadic LMND with snake eyes on MRI with a relatively benign prognosis.

Monomelic amyotrophy: clinical profile and natural history of 279 cases seen over 35 years (1976-2010)

Our objective was to study the clinical characteristics and natural history of monomelic amyotrophy (MMA). We used a retrospective study of 279 patients diagnosed to have either upper (Hirayama disease) or lower limb MMA. Results showed that brachial MMA (BMMA) occurred in 224 patients (male:female, 9:1). Mean age of onset was 19.5 ± 4.18 years. Progression occurred over less than five years in the majority (95.9%) of patients. Duration at the last follow-up was: up to five years in 61.4%, 5-10 in 21.3%, 10-15 in 7.2%, > 15 years in 10.1%. MRI showed asymmetrical lower cervical cord atrophy in 44.6% of patients. Crural MMA (CMMA) occurred in 55 patients (male:female, 13:1). Mean age of onset was 21.38 ± 5.3 years. Similar to BMMA, most cases (65.5%) had onset between 15 and 25 years of age. Total duration of illness at the last follow-up was up to five years in 52.7%, 10 and beyond in 47.3%. In conclusion, a large cohort of patients with monomelic amyotrophy seen over 35 years (1976-2010) is described. Study data support the clinical findings and its natural history with long term follow-up, and the findings emphasize that monomelic amyotrophy is a 'benign' condition with a self-limiting course.

A 20-year-old female with Hirayama disease complicated with dysplasia of the cervical vertebrae and degeneration of intervertebral discs

A 20-year-old female patient was presented with a 1-year history of progressive weakness of the left hand. Examination on admission showed atrophy of the muscles of the left forearm, cold paralysis and minipolymyoclonus. MR images of the cervical cord showed anterior transfer of the cervical cord on anterior flexion and cervical cord compression at the site of cervical kyphosis, confirming the diagnosis of Hirayama disease. Many features of the present case are unusual: the patient is a female (who are rarely afflicted by this disease), with cervical kyphosis and a history of exercise involving cervical vertebral loading, suggesting a potential involvement of the latter two factors in the disease onset. The findings suggest that cervical vertebral dysplasia and intervertebral disc degeneration may influence cervical kyphosis, and be involved in the onset of Hirayama disease.

Hirayama disease

Hirayama disease (juvenile muscular atrophy of distal upper extremity) is a cervical myelopathy. Predominantly affecting male adolescents, it is characterized by progressive muscular weakness and atrophy of distal upper limbs, followed by spontaneous arrest within several years. Although the cause of cervical myelopathy remains unclear, neuropathologic and neuroradiologic findings suggest a forward displacement of the posterior cervical dural sac during neck flexion, causing compression of the cervical cord, and results in atrophic and ischemic changes in the anterior horn. A good understanding of Hirayama disease is essential because early recognition and management can effectively halt the progressive deterioration.

Hirayama disease in children from North America

Hirayama disease has been mainly reported from Asia; only a few cases are from the Western hemisphere, particularly North America. This is a retrospective chart review of patients < 18 years, diagnosed with Hirayama disease from a single center over 10 years. We diagnosed 6 children (4 boys), 15.1 ± 1.2 years of age. Symptom onset was 3 months to 3 years before presentation. All had unilateral or bilateral asymmetric distal upper extremity weakness without objective sensory loss. Oblique amyotrophy and cold paresis were noted in 5. On electromyography, acute-on-chronic denervation was most frequently noted in cervical-8 (C8) and thoracic-1 (T1) myotomes followed by cervical-7 (C7) myotome in both upper limbs, sparing C5-C6 myotomes. Cervical magnetic resonance imaging (MRI) was abnormal in 3. Symptoms progressed over a mean of 16.5 months. Treatment consisted of placement of cervical collar. Heightened awareness of this entity among pediatric neurologists in North America will lead to early diagnosis and intervention, avoiding unnecessary investigations.

Mutational analysis of glycyl-tRNA synthetase (GARS) gene in Hirayama disease

Sporadic juvenile muscular atrophy of the distal upper extremity or Hirayama's disease (HD) and autosomal dominant motor distal neuronopathy/axonopathy (CMT2D/dSMA-V), produced by glycyl-tRNA synthetase (GARS) gene mutations, share some clinical features including: young age of onset, predilection for the distal upper extremity, asymmetry, sparing of proximal muscles and unusual cold sensitivity. However, incomplete penetrance of GARS gene mutations may account for apparently non-familial cases. In order to inquire whether GARS gene mutations are associated with HD we studied seven patients fulfilling the clinical and electrodiagnostic criteria for HD. All patients underwent MRI of cervical spine that excluded compressive myelopathy in neutral position and intramedullary pathology. Each patient was tested for the presence of mutations in GARS by sequencing all coding exons amplified from genomic DNA. No pathogenic mutations were found, excluding the role of GARS gene as a possible factor in the aetiology of HD in this cohort.

Nationwide survey of juvenile muscular atrophy of distal upper extremity (Hirayama disease) in Japan

Juvenile muscular atrophy of the distal upper extremity (JMADUE, Hirayama disease) was first reported in 1959 as 'juvenile muscular atrophy of unilateral upper extremity'. Since then, similar patients in their teens or 20s have been described, under a variety of names, not only in Japan, but also in other Asian countries, as well as Europe and North America. Biomechanical abnormalities associated with JMADUE have recently been reported through various imaging examinations, proposing its disease mechanism. Since JMADUE differs from motor neuron disease, or spinal muscular atrophy, this disease entity should be more widely recognized, and early detection and effective treatments should be considered. We report an epidemiological study in Japan. Two nationwide questionnaire-based surveys, conducted in Japan from 1996 to 1998, identified 333 cases. The numbers of patients per year, distribution of ages at onset, mode of onset, time lapse between onset and quiescence, neurological signs and symptoms, imaging findings, and the effects of conservative treatments were analyzed. The peak age was 15 to 17 years, with a marked male preponderance, usually a slow onset and progression, and quiescence six or fewer years after onset. There was a predominantly unilateral hand and forearm involvement with 'cold paresis'. The imaging findings are described.

Madras motor neuron disease (MMND): clinical description and survival pattern of 116 patients from Southern India seen over 36 years (1971-2007)

Madras motor neuron disease (MMND), MMND variant (MMNDV) and Familial MMND (FMMND) have a unique geographic distribution predominantly reported from Southern India. The characteristic features are onset in young, weakness and wasting of limbs, multiple lower cranial nerve palsies and sensorineural hearing loss. We describe the clinical features and survival pattern in 116 patients with Sporadic MMND, MMND variant and FMMND. A retrospective review of patients' medical records for clinical manifestations, electromyography, imaging, audiological and histopathology findings was performed. Over 36 years (1971 to 2007) 116 patients (men: 59; women: 57) particularly hailing from Southern India were seen. Mean age of onset was 15.8+/-7.9 years. Predominant initial manifestations were impaired hearing with wasting and weakness of distal limb muscles and pyramidal dysfunction. All patients had clinical and/or audiological evidence of hearing impairment. Patients with MMNDV in addition had optic atrophy. The overall mean survival duration was 334.9+/-27.9 months. Thus, Madras motor neuron disease is clinically a distinct entity with features of amyotrophic lateral sclerosis but with young age of onset and presence of auditory neuropathy. Studies to look for environmental and genetic basis of this intriguing disease are necessary to find the causation of this rare disorder.

Benign monomelic amyotrophy with proximal upper limb involvement: case report

Monomelic amyotrophy (MA) is a rare condition in which neurogenic amyotrophy is restricted to an upper or lower limb. Usually sporadic, it usually has an insidious onset with a mean evolution of 2 to 4 years following first clinical manifestations, which is, in turned, followed by stabilization. We report a case of 20-years-old man who presented slowly progressive amyotrophy associated with proximal paresis of the right upper limb, which was followed by clinical stabilization 4 years later. Eletroneuromyography revealed denervation along with myofasciculations in various muscle groups of the right upper limb. We call attention to this rare location of MA, as well as describe some theories concerning its pathophysiology .

Monomelic neurogenic syndromes: a prospective study

Monomelic neurogenic syndromes are rare. Their classification and prognostic features have not been addressed in the European population. A prospective study of 17 patients with monomelic neurogenic amyotrophy, of upper or lower limb onset, with progression limited to one limb for three or more years. Clinical and neurophysiological studies were performed in the subsequent 3 or more years. Fifteen patients were of European origin and two were Asian. Those presenting with proximal monomelic weakness or with involvement of the posterior compartment of the lower leg showed no further progression after the initial period of development of the syndrome. Brisk reflexes in wasted muscles did not predict progression. Electromyographic signs of denervation in the opposite limb at presentation did not predict later progression. Transcranial magnetic stimulation (TMS) features of corticospinal dysfunction were a useful predictor of subsequent progression (p=0.01). One patient with lower limb onset developed conduction block with weakness in an upper limb nine years after presentation, and this upper limb weakness responded to IVIg therapy. This adult-onset European group of patients is different as compared with juvenile-onset Asian cases. The clinical syndromes appear heterogeneous, but neurophysiological investigations, in particular TMS, can be helpful in determining prognosis. Multifocal motor neuropathy should be considered when there is progression, even years after onset.

Subclinical sensory involvement in monomelic amyotrophy

An 18-year-old woman presented with weakness and atrophy in her hand without associated sensory symptoms, preceding events, or structural abnormalities on neuroimaging. No sensory deficits were detected on neurologic examination. Electrophysiological studies showed not only the expected motor findings for monomelic amyotrophy (MA) in the affected limb, but also markedly reduced sensory nerve action potentials when compared with the unaffected side. These findings suggest that subclinical sensory involvement can exist in patients with otherwise classic presentations of MA.

Familial monomelic amyotrophy: a case report from India

Monomelic amyotrophy (MMA) is a benign lower motor neuron disorder in the young with male preponderance. It is characterized by insidious onset and progressive weakness and wasting of a distal extremity over a few years followed by spontaneous arrest. The exact pathogenesis is unknown. It is predominantly a sporadic disorder but rarely familial forms have been documented. In this report, we describe the phenotype of a 21-year-old man and his mother who were diagnosed to have MMA. The index case presented with left upper limb weakness and wasting of 3 years duration while his mother had right upper limb amyotrophy and weakness of 34 years. A total of 190 patients were diagnosed to have MMA in our institute over the last 27 years and this is the first case of familial MMA.

Advanced Hirayama disease with successful improvement of activities of daily living by operative reconstruction

Juvenile muscular atrophy of the distal upper extremity (Hirayama disease) is a benign and non-progressive motor neuron disease. Application of a cervical collar is believed to prevent progression of symptoms in the early stages, but there is no effective therapy for the advanced disease. We found that tendon transfer improved the activities of daily living (ADL) of a patient with advanced Hirayama disease. An operative reconstruction can be valuable, even in patients with Hirayama disease who have developed impaired ADL due to extensive intrinsic hand muscle atrophy.

Unilateral drop finger due to cervical spondylosis at the C6/7 intervertebral level

A 64-year-old man who presented right drop fingers without pyramidal signs due to cervical spondylosis is reported. Magnetic resonance imaging showed a high signal intensity change on T2-weighted scans of the spinal cord at the C6/7 intervertebral level. Evoked spinal cord potentials following ulnar nerve stimulation were attenuated at the C6/7 intervertebral level. Compound muscle action potentials (CMAPs) following right cervical nerve root stimulation were recorded from the extensor digitorum communis. CMAPs following right C8 nerve root stimulation were evoked with small amplitudes. Small polyphasic CMAPs with prolonged onset latency were recorded following right C7 nerve root stimulation. Simultaneous C7 radiculopathy and C8 segmental spinal cord lesion due to cervical spondylosis at the C6/7 intervertebral level were the causes of drop fingers in the present case. Unilateral drop finger is a clinical symptom commonly associated with posterior interosseus nerve palsy, but mention should be made about cervical lesions causing drop finger. Electromyographic abnormalities of the triceps and first dorsal interosseus muscle were the key findings for differentiating the cause from paralysis of the posterior interosseous nerve.

Peripheral and segmental spinal abnormalities of median and ulnar somatosensory evoked potentials in Hirayama's disease

OBJECTIVES

To investigate the origin of juvenile muscle atrophy of the upper limbs (Hirayama's disease, a type of cervical myelopathy of unknown origin).

SUBJECTS

Eight male patients were studied; data from 10 normal men were used as control.

METHODS

Median and ulnar nerve somatosensory evoked potentials (SEP) were recorded. Brachial plexus potentials at Erb's point (EP), dorsal horn responses (N13), and subcortical (P14) and cortical potentials (N20) were evaluated. Tibial nerve SEP and motor evoked potentials (MEP) were also recorded from scalp and spinal sites to assess posterior column and pyramidal tract conduction, respectively.

RESULTS

The most important SEP findings were: a very substantial attenuation of both the EP potentials and the N13 spinal responses; normal amplitude of the scalp N20; and normal latency of the individual peaks (EP-N9-N13-P14-N20). Although both nerves were involved, abnormalities in response to median nerve stimulation were more significant than those in response to ulnar nerve stimulation. There was little correlation between the degree of alterations observed and the clinical state. Latencies of both spinal and cortical potentials were normal following tibial nerve stimulation. The mean latency of cervical MEP and the central conduction time from the thenar eminence were slightly but significantly longer in patients than in controls.

CONCLUSIONS

The findings support the hypothesis that this disease, which is clinically defined as a focal spinal muscle atrophy of the upper limb, may also involve the sensory system; if traumatic injury caused by stretching plays a role in the pathogenesis, the damage cannot be confined to the anterior horn of the spinal cord.

Sporadic lower motor neuron disease with adult onset: classification of subtypes

The discovery of the genetic basis of hereditary lower motor neuron disease (LMND) and the recognition of multifocal motor neuropathy as a distinct clinical entity necessitate a new classification of LMND. To this end, we studied the clinical and electrophysiological features of 49 patients with sporadic adult-onset LMND in a cross-sectional study. Disease duration was more than 4 years to exclude the majority of patients with amyotrophic lateral sclerosis. Based on the pattern of weakness, we identified three groups: 13 patients with generalized weakness (group 1); eight patients with symmetrical, distal muscle weakness (group 2); and 28 patients with non-generalized asymmetrical weakness of the arms in most patients (group 3). Group 3 could be subdivided into patients with weakness in predominantly the distal (group 3a) or the proximal (group 3b) muscle groups, both with disease progression to adjacent spinal cord segments. Distinctive features of group 1 were an older age at onset, more severe weakness and muscle atrophy, lower reflexes, greater functional impairment, more widespread abnormalities on concentric needle EMG, respiratory insufficiency and serum M-protein. In groups 2 and 3, concentric needle EMG findings also suggested a more widespread disease process. Retrospectively, the prognosis of sporadic adult-onset LMND appears to be favourable, because clinical abnormalities were still confined to one limb in most patients after a median disease duration of 12 years. We propose to classify the patients in the different subgroups as slowly progressive spinal muscular atrophy (group 1), distal spinal muscular atrophy (group 2), segmental distal spinal muscular atrophy (group 3a) and segmental proximal spinal muscular atrophy (group 3b). The described clinical phenotypes may help to distinguish between different LMND forms.

Long-term follow-up of 44 patients with brachial monomelic amyotrophy

OBJECTIVES

Monomelic amyotrophy of a single upper limb termed "brachial monomelic amyotrophy" (BMMA) is a benign lower motor neuron disorder in the young, with male preponderance, insidious onset of atrophy and weakness, electromyographic evidence of neurogenic pattern without conduction block, slow progression for 2-4 years followed by a stationary course. The aim of the study was to determine whether (i) atrophy and weakness in the affected limb progresses beyond 5 years; (ii) the illness spreads to the other limbs; and (iii) the disease progresses to amyotrophic lateral sclerosis.

MATERIAL AND METHODS

Forty-four patients who had a duration of illness of 5 years or more at the last follow-up examination were included in the study. Assessment of symptom profile, neurologic deficit and disability was performed at variable intervals during the follow-up period.

RESULTS

Progression of the disease was seen in 37 (84.1%) patients, up to 5 years in 35 (79.5%), 6 years in one and 8 years in another patient. In seven patients (15.9%) the atrophy was accidentally noticed and no further change in the neurologic deficit was observed thereafter. Subsequent to attaining a stationary course, none of the 44 subjects developed fresh symptoms or signs during a mean follow-up period of 9.7 years (range 2.5-23). The mean duration of illness at last follow-up was 12.8 years (range 5-26.5) and in 22 (50%) subjects the disease duration was more than 10 years. Seven patients (15.9%) at presentation had minimal involvement of contralateral upper limb with gross asymmetry and later one more patient developed similar features. Thus, in only a small proportion (18.2%) of patients the neurologic deficit had extended beyond the confines of one upper limb. None of the patients developed involvement of cranial nerves, lower limbs or pyramidal signs.

CONCLUSIONS

Progression of the neurologic deficit in the affected limb was seen up to 5 years in the majority followed by a stationary phase with no evidence of fresh neurologic deficit during the follow-up period. Spread to the contralateral upper limb with minimal neurologic deficit was seen in less than a fifth of the patients, but involvement of lower limbs was not observed. BMMA did not evolve to amyotrophic lateral sclerosis. These observations underscore the benign and self limiting course of BMMA.

Juvenile asymmetric segmental spinal muscular atrophy (Hirayama's disease): three cases without evidence of "flexion myelopathy"

Compression of the cervical spinal cord during neck movements ("flexion myelopathy") was proposed to be the main pathomechanism of juvenile asymmetric spinal muscular atrophy (JASSMA). We present 3 patients with the clinical appearance of JASSMA and typical high-intensity signals in the anterior horn cell region of the lower cervical spinal cord (T2-weighted magnetic resonance images) but without evidence of dynamic spinal cord compression. In all these patients pathomechanism distinct from mechanical damage must be assumed.

Sympathetic skin response in monomelic amyotrophy

OBJECTIVES

Monomelic amyotrophy (MMA) a variant of motor neuron disease, has the characteristic features of wasting and weakness usually confined to a single upper or lower limb occurring predominantly in young males and a benign outcome. Symptoms of increased sweating, coldness and cyanosis have been observed in a few patients. The objective was to evaluate the involvement of the sympathetic nervous system in MMA by measuring sympathetic skin response.

METHODS

Electromyography, motor and sensory nerve conduction studies were done in all the four limbs of 9 patients with atrophy of one upper limb. Stimulation at Erb's point, and above and below elbow was done to look for evidence of conduction block. The sympathetic skin response (SSR) was recorded in all the limbs of these patients. Wasting and weakness of right upper limb in 7 patients and left upper limb in 2 patients was seen. The mean age was 28.3+/-10.1 years. Twenty-five age matched (24.8+/-4.8 years) healthy subjects served as controls.

RESULTS

The mean SSR latency in the affected upper limbs of 9 patients was prolonged compared to the 25 control subjects (1.51+/-0.07 s vs 1.42+/-0.19 s, P=0.03). The mean value of SSR latency in 18 upper limbs of the 9 patients which included atrophied and unatrophied limbs was also prolonged compared to the controls (1.50+/-0.08 s vs 1.42+/-0.19 s, P=0.05). There was no significant difference of the mean latency of SSR between the atrophied upper limbs and the clinically normal upper limbs (1.51+/-0.07 s vs 1.49+/-0.09 s, P=0.51). The mean SSR latency in the lower limbs of the patients (2.09+/-0.09 s) did not significantly differ from the control subjects (1.97+/-0.28 s, P=0.09). Motor and sensory nerve conduction was normal and there was no evidence of conduction block.

CONCLUSION

In MMA the sympathetic nervous system is involved in the atrophic upper limb and also in the clinically unaffected upper limb but not in the lower limbs.

Monomelic amyotrophy with late progression

Monomelic amyotrophy is a sporadic juvenile-onset disease that presents with gradual onset of weakness and atrophy in the hand muscles unilaterally. Generally, this disease is considered a 'benign' and non-progressive motor neuron disease, which stabilizes within five years of onset. We discuss a case that illustrates that monomelic amyotrophy may rarely exhibit late clinical progression to the lower extremities after a prolonged period of disease stability.

Non-progressive juvenile spinal muscular atrophy of the distal upper limb (Hirayama's disease): a clinical variant of the benign monomelic amyotrophy

Hirayama's disease (HD) is frequently found in Asia, and is rarely referred among westerners. It affects young people with higher incidence in males. It is a focal distal amyotrophy with unilateral or asymmetric bilateral involvement of C7, C8 and T1 innervated muscles. HD appears sporadically and has a benign evolution with clinical stabilization in around one year. We report four young male patients with clinical and electrophysiological alterations described in HD, which were followed-up during 5 years. Electromyographic findings were indicative of lower motor neuron involvement. We analyzed cervical MRI aiming at understanding if a questionable spinal cord compression could be implicated in the pathogenesis, but no abnormality was verified. In view of its clinical, and EMG characteristics, HD is no more than a benign monomelic amyotrophy (BMA) clinical variant, and not a specific disease. This eponym could be considered only for the distal upper limb variant (Hirayama's variant) of the BMA.

Benign monomelic amyotrophy: a study of twenty-one cases

A consecutive series of 21 patients with single limb atrophy (monomelic amyotrophy) is reported. Sixteen had lower limb atrophy and five had upper limb involvement. The median age of the onset was 20 years. Characteristic features were sporadic occurrence, wasting confined to one limb, insidious onset with slow progression, stabilizing in 1 to 4 years, and absence of pyramidal signs. All the patients with upper limb involvement were male, however in our cases with lower limb amyotrophy there were no male preponderance. We observed wasting of the entire length of the lower limbs in six patients. There were nine cases with amyotrophy restricted to the leg and one with amyotrophy only in the thigh. In the upper limb in four cases the involvement was distal and in one patient the atrophy was proximal. The electromyographic features were suggestive of anterior horn disease not only in the affected limb but also, in some cases, in clinically uninvolved limb. Cervical or lumbar MRI was normal. MRI of the lower limb disclosed increased signal intensity in the gastrocnemius and soleus muscles in one patient suggesting denervation.

Monomelic amyotrophy following trauma and immobilization in children

Two children aged 9 and 11 years suffered from left elbow sprain and right anterior tibial tuberosity cortical fracture respectively and were treated with plaster cast immobilization for about 30 days. They regained normal strength afterwards, but 9 and 2 months later developed insidious progressive weakness and wasting in the affected limb, mainly evident in the musculature surrounding the site of injury and sparing hand and foot muscles. Two to three years later the condition stabilized. Sensory abnormalities were not found. Electromyographic examination showed neurogenic pattern confined to the impaired extremity. The focal quality and the unusual disposition of muscle involvement suggest a correlation between trauma and/or immobilization and monomelic amyotrophy.

Amyotrophic cervical myelopathy in adolescence

The clinical and radiological features in seven patients who had asymmetric muscular atrophy of the hand and forearm when young are reported and a new hypothesis for its aetiology is proposed. Investigation of body growth curves (a surrogate for velocity of arm growth) showed close relation between (a) the age when the body height increased most rapidly and the onset age of this disorder, and (b) the age when the rapid body growth period ended and the age when symptom progression ceased. Cervical radiological evidence is provided showing asymmetric anterior cord atrophy, disappearance of slackness of dorsal roots in neck extension, and anterior and lateral displacement of the lower cervical cord against the posterior aspects of the vertebral bodies during neck flexion. These results suggest that disproportionate shortening of the dorsal roots is further accentuated during the juvenile growth spurt, which determines the onset and self limited course of the condition, and that repeated neck flexion causes micro-trauma and relative ischaemia of anterior horn cells, which finally results in atrophy of the muscles innervated by motoneurons with long axons. Predisposing anatomical factors are a straight neck due to lack of physiological cervical lordosis and the presence of foreshortened dorsal roots.

AAEM case report #28: monomelic amyotrophy

Monomelic amyotrophy is a rare form of motor neuron disease usually presenting as painless asymmetric weakness and atrophy in the distal upper extremities of young adults. Only rarely are the legs involved and pyramidal findings are uncommon. Monomelic amyotrophy is most often observed in people of Japanese and Indian heritage and affects men almost exclusively. Most cases are sporadic. Laboratory testing is frequently normal or nonspecific except for electrophysiologic studies which typically demonstrate reduced compound muscle action potential amplitudes, fasciculations, and features consistent with acute and chronic denervation in distal upper extremity muscles. Necropsy in 1 patient identified anterior horn cell shrinkage, necrosis, and gliosis in appropriate spinal cord segments. Symptoms and signs often progress for several years before spontaneously arresting. The differential diagnosis for monomelic amyotrophy is broad, including processes which affect the cervical cord, roots, brachial plexus, and individual or multiple nerves in the upper extremity.

The wasted leg syndrome, a single fibre electromyographic study of arms and legs

Single fibre electromyography (SFEMG) was performed on 11 patients with the wasted leg syndrome. Five were of South Asian origin and the others Chinese. In most cases the disorder progressed for about 5 yr before becoming static or very slowly progressive. The SFEMG fibre density was increased similarly in both the affected and less affected leg, but was normal in the arms except for a few longstanding cases. The limited extent of clinical and electrophysiological abnormalities suggests that the wasted leg syndrome is a distinct entity.

Epidural venous system (meningorachidian venous plexus) in juvenile amyotrophy of distal upper extremity: assessment with GD-DTPA enhanced volumetric MR study

The epidural venous system (meningorachidian venous plexus) was analyzed utilizing gadolinium-diethylenetriamine pentaacetic acid (DTPA) (Gd-DTPA) enhanced volumetric magnetic resonance (MR) images in 11 patients with focal cervical spinal cord atrophy, clinically consistent with juvenile amyotrophy of distal upper extremity. In our series, all of the patients showed unusual posterior epidural venous enhancement at the C5-6 level, suggesting posterior epidural venous dilatation. Three patients also showed prominent dilatation of cervico-thoracic epidural veins surrounding the thecal sac. These MR findings were also demonstrated by spinal phlebography. Gd-DTPA enhanced MR images, especially high resolutional volumetric MR images, were efficient for evaluating these vessels. The observation of meningorachidian venous plexus along the disease course should be necessary for searching the pathogenesis of this disease.

Lack of serum neutralizing antibody against poliovirus in patients with juvenile distal spinal muscular atrophy of upper extremities

Serum neutralizing antibodies for type 1, 2 and 3 poliovirus were studied in 15 Chinese patients in Taiwan with juvenile distal spinal muscular atrophy of the upper extremities and 15 age-matched normal subjects. Significantly lower serum antibody titers were found in the study group, suggesting that patients with this chronic focal form of acquired motor neuron disease are, to some degree, immunologically unresponsive to the neutralizing epitope of poliovirus.

Lack of cervical paraspinal muscle involvement in juvenile distal spinal muscular atrophy: an electromyographic study on 15 cases

Electromyography (EMG) of the lower cervical paraspinal muscles was performed in 15 young Chinese males with distal spinal muscular atrophy of the upper extremities. The lack of fibrillation and positive sharp waves in all patients, both in early or active and chronic or steady stages, did not correlate with the EMG status in the affected upper extremity on the same side. This finding is in striking contrast with that in amyotrophic lateral sclerosis.

Congenital cervical spinal muscular atrophy: a non-familial, non progressive condition of the upper limbs

Two patients with congenital cervical spinal muscular atrophy had symmetrical severe muscle weakness and wasting confined to the upper limbs, areflexia and congenital contractures. The shoulders were internally rotated, elbows extended and wrists flexed. There were no sensory or bulbar symptoms, scoliosis, long tract signs or lower limb involvement. This condition should be regarded as a neurogenic type of arthrogryposis, limited to the upper limbs.

Progressive juvenile segmental spinal muscular atrophy

Juvenile segmental spinal muscular atrophy (JSSMA) typically involves the distal upper extremities and follows a benign course over 2-4 years then stabilizes. We report 2 males who presented in their teens with insidious distal upper extremity atrophy and weakness as in typical JSSMA but who then progressed to involvement of the lower extremities and hyperreflexia. There was no sensory loss. Electromyography and muscle biopsy demonstrated features consistent with localized anterior horn cell dysfunction. These patients are noteworthy because they demonstrate that some patients with JSSMA also may have involvement of the lower limbs several years after initial presentation. Progressive JSSMA may be categorized in the clinical spectrum between the spinal muscular atrophies and amyotrophic lateral sclerosis.

Werdnig-Hoffmann disease and chronic distal spinal muscular atrophy with apparent autosomal dominant inheritance

We report on a family in which both Werdnig-Hoffmann disease (severe infantile-onset spinal muscular atrophy) and chronic distal spinal muscular atrophy occurred, with apparent autosomal dominant inheritance. The female proband clinically had Werdnig-Hoffmann disease and died at 10 months. In their second decade of life, the proband's father and his 2 brothers developed bilateral progressive atrophy and weakness of the hands and mild weakness in the distal parts of the legs. Their mother had no symptoms or signs of motor neuron disease but electromyography revealed distal denervation of the limbs. While the family studies suggest autosomal dominant inheritance, it is possible that the proband's condition was influenced by a maternally derived allelic or modifying trait.