Wasted leg syndrome: a clinical, electrophysiological and histopathological study

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.

Wasted leg syndrome: An atypical slowly-progressive form of lower motor neuron disease

We describe four male patients with wasted-leg syndrome, with predominant asymmetric thigh atrophy and weakness that stabilized after a period of slow progression (follow-up 7-18 years). Two patients had an Indian ethnic background and two were Portuguese, without known Indian ancestry. Other mimicking disorders were excluded, but one Indian patient was later diagnosed with CADASIL. Electromyography (EMG) revealed severe chronic neurogenic changes in proximal leg muscles, and mild changes in distal leg muscles, but EMG of the upper limbs was normal. Upper motor neuron signs were absent clinically and on transcranial magnetic stimulation. This seems to represent a variant of the common wasted-leg syndrome presentation.

Monomelic amyotrophy with clinico-radiological and electrophysiological evaluation: A study from Eastern India

Background

Monomelic amyotrophy (MMA) is a benign, rare, sporadic disorder of adolescent and young adults with male predominance, where neurogenic amyotrophy is restricted to an upper or lower limb. It is a variant of lower motor neuron disorder with insidious onset and slow progression for 2-4 years. Paucity of cohort studies as well as relative unawareness among physicians in eastern India stimulated us to do this work.

Material and Methods

Prospective observational study involving 140 cases of MMA from 2012 to 2016, conducted at S.C.B.Medical College, cuttack, Odisha to evaluate clinical profile, electrophysiology and radiological features. All the data were analysed & subjected to statistical analysis through SPSS software version 24.

Results

Mean age at onset and presentation were 19.6yrs and 21.7yrs respectively and the average duration 3.2yrs. Upper limb involvement was more common (91.4%) with distal affection (83%) more than proximal (7%). Isolated Leg amyotrophy found in 12 cases (~9%) and 10 cases were having thigh weakness & atrophy. B/L Upper Limb distal involvement was present in 18.5% cases asymmetrically. Family history found in~2.8%. Autonomic symptoms were present in affected and bilateral homologous Limb in 21%, 5.8%(~6%) patients. Changes in electromyography (EMG) were present in affected limb (100%) and clinically unaffected limb (15%).

Conclusion

MMA is a benign disease of young males with weakness and atrophy confined to unilateral limb or asymmetrical homologous limb and areflexia without sensory loss. It progresses variably for 2-3 years followed by stabilization without progression to Motor neuron disease.

Benign monomelic amyotrophy of lower limb in a cohort of chinese patients

BACKGROUND

Benign monomelic amyotrophy of lower limb (BMALL) is a neurogenic syndrome representing an unclear field. Further studies might be helpful to elucidate uncertainties regarding causation, outcome, and the risk of progression to amyotrophic lateral sclerosis (ALS).

METHODS

According to the inclusion and exclusion criteria, 37 patients with BMALL were retrospectively collected in three neuromuscular centers from January 2012 to October 2018. The detailed medical data were summarized. Multiple laboratory tests were examined. Routine electrophysiological examinations, muscle MRI of lower limbs, and muscle biopsy were conducted.

RESULTS

The cohort included 24 male and 13 female cases with median age of onset 47 years. Muscle MRI revealed that the distribution of involved muscles matched with the extent of fat infiltration, so the pattern muscle atrophy can be divided into the following four types: six patients with thigh atrophy (type I), 14 patients with leg atrophy (type II); 10 patients with disproportionate atrophy in both thigh and leg (type III); and seven patients with well-proportionate atrophy in both thigh and leg (type IV). Electrophysiological findings showed neurogenic pattern, spontaneous activity, and abnormal H reflex, which suggested a disorder of spinal anterior horn cell in the patients with types I-III. However, no electrophysiological abnormalities were found in the patients with type IV. Muscle pathology varied from almost normal pattern to advanced neurogenic pattern in nine biopsied patients. Follow-up showed that two patients with type II developed to ALS four years later, and all patients with type IV were in stable condition without any complaints.

CONCLUSION

Muscle MRI was useful to exactly localize the distribution of involved muscles in BMALL patients. The distribution of atrophic muscles can be roughly divided into four types based on the MRI features. The classification of distributing types might be as an indicator for the prognosis of BMALL.

Clinical evaluation of a 31-year-old woman with crural monomelic amyotrophy

This report describes the clinical presentation of a female patient diagnosed with crural MMA. Careful clinical correlation is necessary to distinguish crural MMA from other motor neuron diseases. When crural MMA is diagnosed, treatment options aim to alleviate symptoms.

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.

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.

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.

Juvenile amyotrophic lateral sclerosis

Juvenile amytrophic lateral sclerosis (JALS) is a type of motor neuron disease presenting before 25 years of age. It is characterized by a combination of upper and lower motor signs. It may be familial or sporadic. We are reporting a sporadic case of JALS with onset of symptoms at 4 years of age. Diagnostic criteria and a brief review of literature are presented.

IgM antibodies to N-acetylgalactosaminyl GD1a in benign monomelic amyotrophy of the lower limb

A male Caucasian patient is presented with a greater than 10-year history of painless weakness of the right leg, stable over the last 7 years. His examination demonstrated severe wasting and moderate weakness of his right calf muscle. Electrodiagnostic study revealed acute denervation of the right calf and chronic partial denervation of multiple right leg muscles. MRI demonstrated atrophy and fatty infiltration of the right calf muscles. Based on previous clinical, electrophysiologic, and radiologic descriptions of this disorder, a diagnosis was made of benign monomelic amyotrophy of the lower limb. Serologic examination for anti-glycoconjugate antibodies revealed high titers of IgM antibodies with selective binding to the disialoganglioside N-acetylgalactosaminyl GD1a (GalNAcGD1a). Testing for antibodies to GalNAcGD1a should be considered in patients with this phenotype. Their presence could suggest a role for immunomodulatory therapy.

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.

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.

Pattern of motor neurone disease in eastern India

A clinical study about the pattern of motor neurone disease in eastern India was carried out from July 1993 to June 1995 at Bangur Institute of Neurology, Calcutta and SSKM Hospital, Calcutta. A total of 110 cases were studied and they constituted 0.11% of all neurological cases seen in the general OPD. Of 110 cases, amyotropic lateral sclerosis (ALS) constituted 43.6%, progressive muscular atrophy (PMA) 10.9%, post-polio progressive muscular atrophy (PPMA) 1.8%, spinal muscular atrophy (SMA) 20%, atypical form Madras pattern of MND (MMND) 0.9% and monomelic amyotrophy (MMA) 22.7% of cases. Disease is more common in males than females and average duration of symptoms before presentation varied from 1 to 12 months. Most of the patients were either agricultural labourers or manual workers in ALS variety whereas MMA variety was evenly distributed in both hard labourers and sedentary workers. Most of the patients in MMA and SMA groups presented before 30 years of age whereas ALS and PMA group presented after 30 years. Trauma was the commonest antecedent event in ALS and MMA followed by electrocution in the same two groups. Family history was found to be absent in SMA group though the disease is considered as a hereditary one. Weakness of the limbs and wasting of the muscles were common presenting symptoms and signs. Bulbar symptoms and signs were found only in the ALS group. EMG showed neurogenic pattern and mixed pattern in most of the patients in all groups. Only a few patients showed myopathic pattern. Neuroimaging study helped in exclusion of compressive lesion excepting two cases of MMA where facetal hypertrophy was present. Monomelic amyotrophy, a special variety of motor neurone disease, is not rare in this part as compared to other parts of India and Asia.

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.

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.

Monomelic amyotrophy in siblings

Monomelic amyotrophy is a rare, benign motor neuron disorder. Electrophysiologic studies are suggestive of localized chronic anterior horn cell disease. Two young siblings are reported with monomelic amyotrophy who had proximal muscle weakness confined to one arm. We propose that monomelic amyotrophy, at least in this family, is inherited as an autosomal recessive trait.

Madras pattern of motor neuron disease in South India

This paper presents the clinical features in 12 patients with the Madras pattern of motor neuron disease (MMND) seen over a period of 10 years. Ten of the patients were from other parts of South India, outside Madras. Young age at onset, sporadic occurrence, sensorineural deafness, bulbar palsy, diffuse atrophy with weakness of limbs and progressive but benign course were the striking features. Electromyography revealed chronic partial denervation. MMND formed 3.7% of all forms of motor neuron disease. Although isolated cases have been seen elsewhere in India, this is the first report of a large number of patients of MMND seen outside Madras (Tamil Nadu). Recognition of this clinical syndrome is of importance for prognostication and as well for search of possible aetiological factors.