Focal cervical poliopathy causing juvenile muscular atrophy of distal upper extremity: a pathological study

Benign monomelic amyotrophy of lower limb: a rare entity with a characteristic muscular CT

Six patients presented with amyotrophy confined to a single lower limb and characterized by insidious onset, slow progression and later stabilization. Wasting was out of proportion with disability and there were no sensory, pyramidal tract or bulbar signs. All cases were sporadic, and there was no history of poliomyelitis. CK, anti-ganglioside antibodies, motor and sensory conductions were normal. Quantitative EMG and muscle biopsy revealed neurogenic features also in clinically unaffected limbs. Muscular CT showed selective or predominant, asymmetrical involvement of posterior leg muscles and caput longus of biceps femoris. Monomelic amyotrophy of lower limb is a clinically localized variant of spinal muscular atrophy with a particularly benign course. Although in the early stage there are no clinical or laboratory findings which allow differential diagnosis with other motor neuron diseases, the history of an amyotrophy clinically localized for more than 3 years to a lower single limb and the characteristic muscular CT pattern suggest the diagnosis since the first observation and indicate a favorable prognosis.

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.

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.

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.

Computed tomographic myelography characteristics of spinal cord atrophy in juvenile muscular atrophy of the upper extremity

Although atrophy of the lower cervical and upper thoracic cord in juvenile muscular atrophy of distal upper extremity has been reported, the atrophic patterns of the cord, especially in the transverse section, have not been studied extensively. The aim of this study is to clarify the atrophic patterns of the cord by CT myelography (CTM) and to discuss the pathogenesis of cord atrophy. Sixteen patients with juvenile muscular atrophy of distal upper extremity were examined by CTM. Atrophy of the lower cervical and upper thoracic cord, consistent with the segmental weakness, was seen in all patients. Flattening of the ventral convexity was a characteristic atrophic pattern of the cord. Bilateral cord atrophy was commonly observed; eight of 12 patients with unilateral clinical form and all four patients with bilateral form showed bilateral cord atrophy with dominance on the clinical side. There was no correlation between the degree of cord atrophy and duration of symptoms. Flattening of the ventral convexity, associated with purely motor disturbances, reflects selective atrophy of the anterior horns in the cord, which is attributable to chronic ischemia. Cord atrophy proved to precede clinical manifestations. The characteristic atrophy of the cord provides useful information to confirm the diagnosis without long-term observation.

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.

Juvenile distal spinal muscular atrophy of upper extremities in Chinese males: a single fibre electromyographic study of arms and legs

Single fibre electromyography (SFEMG) was performed on six young Chinese males with distal spinal muscular atrophy of the upper extremities. Abnormal SFEMG findings of increased fibre density, jitter and blocking were recorded over both arms and legs in all patients, suggesting a more generalised disturbance than would appear clinically.

Monomelic atrophy

Weakness of distal muscles of one upper limb which progresses over 1 year and then appears to arrest ("monomelic amyotrophy") has been reported mainly in Japan and India. We report 5 cases of a similar syndrome occurring in Canada. In our cases the wasting affected the forearm muscles of one upper limb (sparing brachioradialis and extensor carpi radialis). There was minimal wasting and electromyographic changes in the opposite upper limb. The CT myelogram showed unilateral wasting of the cervical cord.

New insights in motor neuron disease

In motor neuron disease there is a characteristic pattern of nerve cell loss and degeneration of related pathways. In surviving anterior horn cells several morphologically distinct, but generally non-specific, intracytoplasmic inclusion bodies have been recognized. Recently accumulations of previously unrecognized ubiquitinated material have been described in surviving neurons, which cannot be demonstrated with routine histological methods. These changes appear unique to this disease, and provide a new insight into the underlying pathology that may help understand the pathogenesis of this intriguing disorder. In this article we review the new information on the clinical, toxicological and pathological features of the disease.

Non familial juvenile distal spinal muscular atrophy of upper extremity

An uncommon variety of non familial, juvenile onset, spinal muscular atrophy with asymmetric distal upper extremity affection is described. One hundred and two patients with a one to 14 year follow up are analysed. Spinal muscular atrophies with a distal distribution are rare. However, in the past three decades, previously unrecognised varieties of neurogenic muscular atrophy have been described in Asia (Japan, India, Sri Lanka and Singapore) under a variety of names. These provide interesting data for discussion of Asian neurogenic muscular atrophies with distal affection, in the context of diseases of the motor neuron.