Complex repetitive discharges: cause or effect of neurogenic muscle hypertrophy?

Neurogenic muscle hypertrophy in type III spinal muscular atrophy

Neurogenic muscle hypertrophy is very unusual and has been rarely described. We described a 25-year-old woman presented with proximal muscle weakness with calf muscle hypertrophy. Limb magnetic resonance imaging scans showed increased muscle bulk without fatty changes, and a muscle biopsy revealed prominent hypertrophic type II muscle fibers. A mutation in SMN1 was found in a genetic analysis. This is the first report of neurogenic muscle hypertrophy seen in genetically confirmed spinal muscular atrophy III.

Muscle hypertrophy of the lower leg caused by L5 radiculopathy

We report on a case with hypertrophy of the tibial muscles and to a lesser extent of the calf muscles preceded by a lumbar syndrome and sciatica. Lumbar myelography disclosed a discogenic compression of the L5 nerve root. Muscle biopsy of the peroneal muscles showed a marked type I fibre predominance and hypertrophy but no inflammatory infiltration. We consider the possibility that radiculopathy not only of the S1 nerve root but also of the L5 root can trigger hypertrophy of the musculature and must be taken into account of the differential diagnosis of unilateral focal hypertrophy of the lower leg.

Myopathic changes in bilateral hypertrophy of the first dorsal interosseus muscle of the hand

A 43-year-old healthy man presented with bilateral hypertrophy of the first dorsal interosseus muscles of both hands. Neurophysiologic and laboratory examinations revealed no pathologic findings. Doubled muscle width was found by ultrasound. Myopathic changes were present in muscle biopsy with varying fiber sizes but without inflammatory features. The clinical impression of massive bilateral symmetric enlargement of the first dorsal interosseus muscles was characterized by subtle, non-specific muscular pathology.

Isolated spinal accessory mononeuropathy associated with neurogenic muscle hypertrophy: restricted neuralgic amyotrophy or stretch-palsy? A case report

A 55-year-old man developed transient bi-brachial paresthesias followed by severe pain over his left shoulder ridge and periscapular region within 8 hours of rigorous hand-over-hand hoisting of a 33.8-kg (75-lb) object. He experienced weakness in shoulder abduction followed several weeks later by focal hypertrophy of the left trapezius. Electrophysiologic studies showed significant spontaneous motor activity in the form of denervation potentials, fasciculations, and complex repetitive discharges. The 2 major diagnostic considerations were restricted neuralgic amyotrophy versus stretch palsy of the spinal accessory nerve. The clinical similarities and differences between restricted forms of neuralgic amyotrophy and stretch palsies are discussed.

Muscle hypertrophy with complex repetitive discharges in C-6 radiculopathy

OBJECTIVE

To report on a case of post-denervation muscle hypertrophy in an unusual distribution.

CASE REPORT

A 52-year-old patient with severe flaccid paraparesis after polio developed unilateral C-6 radiculopathy that resolved with conservative treatment. Within 2 years marked hypertrophy, stiffness and pain in the muscles in the affected myotome developed. EMG discovered abundant complex repetitive discharges (CRD) within hypertrophic muscles. On biopsy, true hypertrophy of muscle fibers and some group atrophy was found. Steroid treatment relieved the symptoms and significantly suppressed the CRD. The possible causative role of CRD for hypertrophy in partially denervated muscle is discussed.

Hypertrophie musculaire neurogène : à propos de trois cas, imagerie et revue de la littérature

OBJECTIVE

To review the literature on well-documented cases of neurogenic muscle hypertrophy in order to define significant features of this disease.

PATIENTS AND METHODS

The PUBMED and SCIENCE DIRECT web-sites were used to conduct an inventory of all reported cases of this disease. We entered the key-words "hypertrophy", "muscle" and "neurogenic", and found 48 articles, describing 129 cases. Our criteria of inclusion included hypertrophy of one or several muscles of a lower limb, previous realization of at least one imaging study (CT or MRI) and electromyography of lower limbs; criterion of exclusion was hypertrophy related to hereditary or acquired polyneuropathies. Twenty-five cases were retained for investigation along with 3 recent cases observed in our department.

RESULTS

Results show that neurogenic muscle hypertrophy is usually presents with painful enlargement of a calf in a male, aged 32 to 60 years, with previous history of low back pain and sciatica, 68% of the time due to disk herniation or lumbar stenosis. Other clinical findings may include radiation therapy or trauma.

CONCLUSION

The symptoms of neurogenic muscle hypertrophy may lead to MRI examination before electromyography. This disease should be included in the differential diagnosis.

Effects of lesions of the human posterior thalamus on ocular fixation during voluntary and visually triggered saccades

OBJECTIVE

To investigate the role of the posterior thalamus in controlling voluntary and visually triggered eye movements and ocular fixation.

METHODS

The latency to initiate saccades to peripheral targets (visually triggered) and in response to verbal commands (voluntary) was measured in three patients with unilateral lesions of the posterior thalamus, in normal controls, and in neurological controls with Parkinson's disease. On half the trials a fixation point offset simultaneously with target onset, and on half it remained visible.

RESULTS

Offset of the fixation point simultaneous with target onset decreased saccade latency for both voluntary and visually triggered eye movements in controls, but only for voluntary saccades in patients with thalamic lesions.

CONCLUSIONS

These findings suggest that separate neural systems control fixation when making voluntary and visually triggered eye movements, and that the thalamus is involved in the control of fixation for visually triggered but not for voluntary saccades.

Focal myositis associated with S-1 radiculopathy: Report of two cases

Two cases are described of pseudotumoral calf hypertrophy after laminectomy for a compressive S-1 radiculopathy. The serum creatine kinase (CK) level was normal or mildly elevated. T2-weighted magnetic resonance imaging (MRI) showed calf enlargement, with an increased signal of the medial head of the gastrocnemius muscle. Electromyography revealed fibrillation potentials and positive sharp waves, but no complex repetitive discharges in the affected gastrocnemius muscle, with motor unit potentials having mixed neurogenic and myopathic features. Muscle biopsy revealed a focal myositis associated with some features of denervation. A brief course of corticosteroids was followed by remission clinically and improvement in the MRI findings.

Segmental neurogenic muscle hypertrophy associated with radiation injury

A 48-year-old man presented with painless left trapezius hypertrophy 20 years after radiotherapy for nasopharyngeal carcinoma. EMG sampling showed myokymic discharges, reduced polyphasic motor unit recruitment and no signs of active denervation. The relationship between radiotherapy, brachial plexopathy and neurogenic muscle hypertrophy is discussed.