Isolated muscle hypertrophy as a sign of radicular or peripheral nerve injury

Muscle hypertrophy following acquired neurogenic injury: systematic review and analysis of existing literature

OBJECTIVES

Neurogenic muscle hypertrophy (NMH) is a rare condition characterized by focal muscle hypertrophy caused by chronic partial nervous injury. Given its infrequency, underlying mechanisms remain poorly understood. Inspired by two clinical cases, we conducted a systematic review to gain insights into the different aspects of NMH.

METHODS

We systematically searched online databases up until May 30, 2023, for reports of muscle hypertrophy attributed to acquired neurogenic factors. We conducted an exploratory analysis to identify commonly associated features. We also report two representative clinical cases.

RESULTS

Our search identified 63 reports, describing 93 NMH cases, to which we added our two cases. NMH predominantly affects patients with compressive radiculopathy (68.4%), negligible muscular weakness (93.3%), and a chronic increase in muscle bulk. A striking finding in most neurophysiological studies (60.0%) is profuse spontaneous discharges, often hindering the analysis of voluntary traces. Some patients exhibited features consistent with more significant muscle damage, including higher creatine phosphokinase levels, muscle pain, and inflammatory muscle infiltration. These patients are sometimes referred to in literature as "focal myositis." Treatment encompassed corticosteroid, Botulinum Toxin A, decompressive surgery, antiepileptic medications, and nerve blocks, demonstrating varying degrees of efficacy. Botulinum Toxin A yielded the most favorable response in terms of reducing spontaneous discharges.

INTERPRETATION

This systematic review aims to provide a clear description and categorization of this uncommon presentation of an often-overlooked neurological disorder. Though questions remain about the underlying mechanism, evidence suggests that aberrant fiber overstimulation along with increased workload that promotes focal damage may result in muscle hypertrophy. This may serve as a guide for therapeutic interventions.

Denervation pseudo hypertrophy of the calf: An important cause of lower limb swelling

Denervation pseudohypertrophy is an uncommon cause of limb swelling, which may be overlooked. It is an important diagnosis to arrive at, as it instructs the search for an underlying cause which may itself require intervention. We present the case of a 32-year-old male rugby player with a 2-year history of left calf swelling and intermittent pain and tightness. He described a previous history of 2 left sided lumbar micro-discectomy surgeries. There was no tenderness or sensory deficit on examination. MRI of the left calf revealed muscular enlargement, with fat interspersed between the muscle fibers, in keeping with pseudohypertrophy. This has a number of causes, in this cause attributed to lumbar radiculopathy. This case highlights a rare but important cause of limb swelling which should be considered in the workup of a unilateral swollen limb.

Epidural stimulation for cardiovascular function increases lower limb lean mass in individuals with chronic motor complete spinal cord injury

NEW FINDINGS

What is the central question of this study? Spinal cord injury results in paralysis and deleterious neuromuscular and autonomic adaptations. Lumbosacral epidural stimulation can modulate motor and/or autonomic functions. Does long-term epidural stimulation for normalizing cardiovascular function affect leg muscle properties? What is the main finding and its importance? Leg lean mass increased after long-term epidural stimulation for cardiovascular function, which was applied in the sitting position and did not activate the leg muscles. Leg muscle strength and fatigue resistance, assessed in a subgroup of individuals, also increased. These adaptations might support interventions for motor recovery and warrant further mechanistic investigation.

ABSTRACT

Chronic motor complete spinal cord injury (SCI) results in paralysis and deleterious neuromuscular and autonomic adaptations. Paralysed muscles demonstrate atrophy, loss of force and increased fatigability. Also, SCI-induced autonomic impairment results in persistently low resting blood pressure and heart rate, among other features. We previously reported that spinal cord epidural stimulation (scES) optimized for cardiovascular (CV) function (CV-scES), which is applied in sitting position and does not activate the leg muscles, can maintain systolic blood pressure within a normotensive range during quiet sitting and during orthostatic stress. In the present study, dual-energy X-ray absorptiometry collected from six individuals with chronic clinically motor complete SCI demonstrated that 88 ± 11 sessions of CV-scES (7 days week^-1 ; 2 h day^-1 in four individuals and 5 h day^-1 in two individuals) over a period of ∼6 months significantly increased lower limb lean mass (by 0.67 ± 0.39 kg or 9.4 ± 8.1%; P < 0.001). Additionally, muscle strength and fatigability data elicited by neuromuscular electrical stimulation in three of these individuals demonstrated a general increase (57 ± 117%) in maximal torque output (between 2 and 44 N m in 14 of the 17 muscle groups tested overall) and torque-time integral during intermittent, fatiguing contractions (63 ± 71%; between 7 and 230% in 16 of the 17 muscle groups tested overall). In contrast, whole-body mass and composition did not change significantly. In conclusion, long-term use of CV-scES can have a significant impact on lower limb muscle properties after chronic motor complete SCI.

Neurogenic calf amyotrophy with CK elevation by entrapment radiculopathy; clinical, radiological, and pathological analyses of 18 cases

OBJECTIVE

To characterize the clinical, radiological, and pathological manifestations of 18 cases showing neurogenic calf amyotrophy with creatine kinase (CK) elevation by entrapment radiculopathy (NCACKEER).

METHODS

We retrospectively reviewed and evaluated the medical records of patients who complained of weakness or atrophy of the calf muscles in our department between 2004 and 2019. We identified 18 cases fulfilling the proposed criteria of NCACKEER. We extracted neurological, laboratory, neurophysiological, and neuroradiological data from all cases. Moreover, we evaluated biopsy specimens from the gastrocnemius in four cases.

RESULTS

Eighteen NCACKEER cases exhibited the characteristic findings that can discriminate previously known myopathies or polyneuropathies affecting distal legs. We noticed male predominance (72%) with an average age at diagnosis of 65.6 years. Muscle weakness or atrophy was localized in the distal legs, with Achilles tendon reflexes absent in all cases. We observed elevated serum CK levels with a range from 237 to 2294 IU/L. All electromyography (EMG) studies showed neurogenic changes in the affected muscles. Lumbar spinal MRI exhibited either spinal canal stenosis at various vertebral levels or intervertebral foraminal stenosis at L4/5 and L5/S1 in all cases with significant straightening spinal and sacral alignments. All muscle biopsy specimens showed findings of neurogenic muscular degeneration with no inflammatory infiltrations. Cases with higher CK elevation had more necrotic muscle fibers.

CONCLUSION

We established the clinical characteristics of NCACKEER. Evaluations of serum CK level and skeletal muscle CT imaging are useful for screening, and lumbar spinal MRI, EMG and/or muscle biopsy are necessary for diagnostic confirmation.

[Continuous hyperCKemia without calf muscle hypertrophy associated with S1 radiculopathy]

A 72-year-old man presented with continuous hyperCKemia and intermittent claudication. He exhibited no calf muscle hypertrophy at that time or afterward. Other than an increased creatine kinase (CK) level (1,525 U/l), none of the laboratory tests was abnormal, including that for myositis-related autoantibodies. Electromyography showed neurogenic changes in the left gastrocnemius. Lumbar magnetic resonance imaging revealed spinal canal stenosis (L3/4, L4/5), left L4 radiculopathy, and bilateral S1 radiculopathy. T₂-weighted and short tau inversion recovery images showed high signal intensity in the bilateral biceps femoris and gastrocnemius. Histopathological evaluation of a specimen obtained from the right gastrocnemius muscle revealed neurogenic changes. The patient was diagnosed with S1 radiculopathy caused by lumbar spinal canal stenosis with hyperCKemia. Although S1 radiculopathy with hyperCKemia is usually associated with calf muscle hypertrophy, we should consider S1 radiculopathy in patients with intermittent claudication and hyperCKemia even in the absence of calf muscle hypertrophy.

Neurogenic muscle hypertrophy in a 12-year-old girl

Muscular hypertrophy secondary to denervation is very rare, but well-documented phenomena in adults. This is the first report of a child with neurogenic unilateral hypertrophy due to S1 radiculopathy. A 12-year-old girl presented with left calf hypertrophy and negative history of low back pain or trauma. The serum creatinine kinase level and inflammatory markers were normal. Magnetic resonance imaging showed muscle hypertrophy of the left gastrocnemius and revealed a protruded lumbar disc at the L5-S1 level. The protruded disc abuts the S1 root on the left side. Electromyography showed mild left S1 radiculopathy. Passive stretching and work load might clarify the origin of neurogenic hypertrophy but there is still a need for further evidence. Clinical, laboratory, magnetic resonance imaging and electromyography findings showed that S1 radiculopathy could be a cause of unilateral calf swelling in youth even in the absence of a history of back or leg pain.

Neurogenic muscle hypertrophy: a case report

Muscular hypertrophy is caused mainly due to myopathic disorder. But, it is also rarely produced by neurogenic disorder. A 74-year-old woman complained of right calf pain with hypertrophy for several years. Recent lumbar spine magnetic resonance imaging (MRI) showed central and lateral canal narrowing at the L4-L5 intervertebral space. Lower extremity MRI revealed fatty change of right medial head of the gastrocnemius and soleus, causing right calf hypertrophy. Electrodiagnostic examinations including electromyography and nerve conduction velocity testing demonstrated 5th lumbar and 1st sacral polyradiculopathy. Integrating all the results, the diagnosis was neurogenic muscle hypertrophy. Neurogenic muscle hypertrophy is very rare, but we recommend that clinicians consider this problem when a patient complains of lower limb hypertrophy and pain.

Congenital Bimelic Hypertrophy of the Hands

Congenital hypertrophy of the hand is a rare phenomenon. The condition is characterized by hypertrophy of muscles, varies in severity and has been reported under different names. Some patients also have aberrant muscles. Electromyography is unremarkable, and the signal intensity on MRI and ultrasound is normal. The etiology is unknown and does not seem to be confined to a peripheral nerve, part of the plexus or nerve root. The condition is assumed to be congenital. We report a 28-year-old male with asymmetric hypertrophy of both hands and give a review of the 4 other cases known so far.

Electrically induced muscle cramps induce hypertrophy of calf muscles in healthy adults

OBJECTIVES

Skeletal muscles usually cramp at short lengths, where the tension that can be exerted by muscle fibers is low. Since high tension is an important anabolic stimulus, it is questionable if cramps can induce hypertrophy and strength gains. In the present study we investigated if electrically induced cramps (EIMCs) can elicit these adaptations.

METHODS

15 healthy male adults were randomly assigned to an intervention (IG; n=10) and a control group (CG; n=5). The cramp protocol (CP) applied twice a week to one leg of the IG, consisted of 3x6 EIMCs, of 5 s each. Calf muscles of the opposite leg were stimulated equally, but were hindered from cramping by fixating the ankle at 0° plantar flexion (nCP).

RESULTS

After six weeks, the cross sectional area of the triceps surae was similarly increased in both the CP (+9.0±3.4%) and the nCP (+6.8±3.7%). By contrast, force of maximal voluntary contractions, measured at 0° and 30° plantar flexion, increased significantly only in nCP (0°: +8.5±8.8%; 30°: 11.7±13.7%).

CONCLUSION

The present data indicate that muscle cramps can induce hypertrophy in calf muscles, though lacking high tension as an important anabolic stimulus.

Focal myositis--neurogenic phenomenon?

We report four cases of focal myositis. The patients, three men and one woman, had painful muscle hypertrophy, affecting four different sites. MRI confirmed the muscle enlargement and oedema. Electromyography revealed evidence of acute and chronic denervation in all four cases. Muscle biopsy was available in three and confirmed features suggestive of focal myositis. Based on our patient material, we suggest that chronic nerve irritation, such as compression, can lead to muscle hypertrophy which, when prolonged, provokes fibre necrosis and secondary inflammation. Our finding in four patients having hypertrophy involving four different sites, leads us further to suggest that this may be the common mechanism behind focal myositis.

Pathological mechanism of lumbar disc herniation resulting in neurogenic muscle hypertrophy

We present a 33-year-old man with 5-year history of low back pain who presented with an enlarging right calf. The patient underwent an extensive workup including biopsy without diagnosis. The patient's examination was significant for diminished pinprick sensation in the right L5/S1 dermatome. Reflexes were absent in the right ankle. The circumference of the right calf (58 cm) was twice that of the left. MRI revealed a herniated lumbar disc at the L5/S1 level. He then underwent a L5/S1 microdiscectomy. Following this surgery, the patient noted complete resolution of all sensory deficits in his lower extremity. His calf circumference had decreased by 5 cm at 4 months and by a total of 8 cm at his 2-year post-operative visit. Histological examination of the affected muscle demonstrated severe grouped atrophy of both type I and type II fibers. There was also evidence of compensatory fiber hypertrophy as well as fiber splitting. We concluded that the patient suffered from a herniated lumbar disc causing radiculopathy with calf hypertrophy (neurogenic hypertrophy). To our knowledge this is the first report of both grouped atrophy and compensatory hypertrophy of both muscle fiber types seen in this phenomenon.

Various tumor-mimicking lesions in the musculoskeletal system: causes and diagnostic approach

Tumor-mimicking lesions in the musculoskeletal system can be defined as lesions mistaken as tumors due to the presence of palpation upon physical examination or a tumor-like appearance upon radiological examination. Moreover, tumor-mimicking lesions show diverse etiologies and anatomic locations. We illustrated the various tumor-mimicking lesions involving bone and soft tissue. In this review, the tumor-mimicking lesions were classified into those based on clinical examination and those based on radiological examination in musculoskeletal radiology. Awareness of the various causes of tumor-mimicking lesions, correctly obtaining clinical information, and the proper selection of imaging modality are important for the differentiation of tumor-mimicking lesions from true neoplasms.

[Post-traumatic focal fixed dystonia of the shoulder: a distinctive syndrome with speculative mechanisms?]

INTRODUCTION

Whether post-traumatic focal fixed dystonia has a physiological or psychologically-mediated mechanism is discussed.

CASE REPORT

We report the case of an active 22-year-old soldier with shoulder-fixed dystonia, eight months after a fall with minor right-acromioclavicular sprain.

CONCLUSION

Psychiatric examination and search of complex regional pain syndrome, radicular or accessory nerve damage, and genetic predisposition to dystonia are necessary for selecting a difficult treatment in these patients.

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.

Persistent abnormal shoulder elevation after accessory nerve injury and differential diagnosis with post-traumatic focal shoulder-elevation dystonia: report of a case and literature review

We report on a patient with persistent abnormal shoulder posture associated with isolated neurogenic hypertrophy of the trapezius muscle due to accessory nerve injury. The patient complained of marked difficulty in shoulder elevation and abduction. Over 6-month treatment with botulinum toxin, there was a complete resolution.

Congenital monomelic neurogenic disorder with calf muscle hypertrophy

An 8-year-old girl had hypertrophy of the right calf muscle since birth, with progressive ankle contracture and mild muscle weakness. Her right leg was 3 cm shorter than her left. Electromyography and biopsy of the affected muscle showed neurogenic changes. She also had neurogenic bladder and spina bifida occulta at the S1 level. We believe that the spina bifida was responsible for the neurogenic changes in her right calf, but could not find definite evidence for this association. Although cases with neurogenic muscle hypertrophy, especially calf muscle hypertrophy, have been reported, none of them was congenital or associated with spina bifida occulta.

Unilateral calf hypertrophy seen in lumbosacral stenosis: case report and review of the literature

STUDY DESIGN

A case report of a patient with neurogenic unilateral calf hypertrophy and review of the literature are reported.

OBJECTIVES

To provide further evidence that S1 radiculopathy is predisposed to develop neurogenic muscle hypertrophy.

SUMMARY OF BACKGROUND DATA

Calf hypertrophy, specifically hypertrophy of the gastrocnemius muscle, is a rare but recognized presentation of S1 and less commonly L5 radiculopathies. The pathophysiology of this is incompletely understood.

METHODS

We present a 59-year-old patient with painless progressive distal right leg weakness and calf enlargement. Electrodiagnostic studies and MAGNETIC RESONANCE IMAGING scanning were performed to evaluate the extent and cause of radicular damage as the etiology for unilateral calf hypertrophy.

RESULTS

Examination and electrodiagnostic studies revealed right L5, right S1, and left L5 radiculopathies. Imaging studies demonstrated lumbar stenosis at L3-L4, L4-L5, and L5-S1 vertebral levels as well as L4-L5 and L5-S1 foraminal stenosis. After decompressive surgery the progressive nature of the patient's symptomatology halted, and he had partial resolution of his deficits.

CONCLUSION

Although the patient had bilateral L5 radiculopathies, he only had hypertrophy in the distribution of his right S1 radiculopathy. This supports the hypothesis that dysfunction of the S1 nerve root or its distribution is a predisposing factor to develop neurogenic muscle hypertrophy. Furthermore, patients presenting with unilateral calf hypertrophy need a careful diagnostic evaluation for S1 radiculopathy as well as to exclude asymmetric presentation of systemic neuromuscular conditions.

Imaging of sports-related muscle injuries

Muscle derangements in athletes have a wide variety of causes, treatments, and prognoses. Given that the cause and severity of sports-related injuries may be difficult to determine clinically in some cases, MR imaging is utilized increasingly to evaluate muscle injuries in athletes. After reviewing useful MR imaging techniques, this article focuses on MR imaging of the most common causes of muscle pain and disability in athletes, including myotendinous strain, delayed onset muscle soreness, muscle contusion, myositis ossificans, muscle laceration, muscle herniation, and compartment syndrome. The differential diagnosis of various signal intensity abnormalities in muscle also is reviewed.

Clinical and pathologic features of focal myositis

To clarify the nosology of focal myositis (FM), we report the clinical and pathologic features of eight patients presenting with focal enlargement of one muscle. Most patients improved without immunosuppressive therapy, and none developed polymyositis. Pathologic features were those of an inflammatory myopathy, with muscle fiber hypertrophy and moderate to severe inflammation. In most cases, a clustering of tightly packed muscle fibers, enveloped by a thick bundle of fibrosis, was associated with the diagnosis of FM. Immunohistochemistry showed T cell predominance within the interstitial infiltrates in all cases. No evidence of vasculitis was present. Our findings suggest that FM is a benign condition that has certain clinical features separating it from other inflammatory myopathies. Pathologic changes, such as large clusters of nesting muscle fibers surrounded by thick fibrosis, are more characteristic of FM than polymyositis.

Focal shoulder-elevation dystonia

We describe 13 cases of isolated focal dystonia of the shoulder with dystonic elevation but without clinically obvious cervical dystonia. All had significant trapezius muscle hypertrophy and limitation of shoulder movement causing substantial morbidity. In nine, this developed in the immediate aftermath of shoulder region trauma, most often a motor vehicle accident; clinically significant head trauma was not a factor. In two other cases this developed in the context of chronic heavy labor (suggesting possible overuse) and in one other it developed concurrent with the symptoms of discogenic cervical (C6-7) radiculopathy. In the one remaining case, no precipitating factors were identified. Preexisting risk factors for dystonia, such as dopamine antagonist drug use, family history of dystonia, or prior brain injury, were not identified in these patients. Administration of medications used to treat dystonia was unsuccessful but botulinum toxin therapy was beneficial in all six treated cases.

Comparison of acute- and delayed-onset posttraumatic cervical dystonia

Head, neck, or shoulder trauma is an occasional antecedent event before the appearance of cervical dystonia. A clinically distinctive syndrome of acute-onset posttraumatic cervical dystonia characterized by markedly restricted range of neck motion, absence of phasic involuntary movements, and poor response to treatment has previously been described. Patients with cervical dystonia attending a movement disorder clinic were reviewed for history of trauma before onset of symptoms. Patients with symptom onset within 4 weeks of trauma were compared with patients who developed symptoms between 3 months and 1 year after trauma. Acute-onset cervical dystonia was characterized by markedly reduced cervical mobility; prominent shoulder elevation with trapezius hypertrophy in most patients, absence of involuntary movements, sensory tricks, or activation maneuvers; and poor response to botulinum toxin injection. By contrast, delayed-onset cervical dystonia was clinically indistinguishable from nontraumatic idiopathic cervical dystonia. Acute-onset posttraumatic cervical dystonia is similar to limb dystonia after peripheral trauma and may represent a form of nondystonic muscle spasm similar to torticollis associated with musculoskeletal injuries of the cervical spine and craniocervical junction.

AAEM minimonograph #46: neurogenic muscle hypertrophy

Muscle hypertrophy occurs uncommonly in several neurogenic disorders including neuropathies, radiculopathies, spinal muscular atrophy, and post-polio syndrome. Its pathogenesis varies in different circumstances. In the presence of generalized myokymia and neuromyotonia (Isaacs' syndrome), symmetrical hypertrophy appears to be the result of continuous spontaneous electrical stimulation of myofibers and, in some cases, results in type 1 myofiber preponderance. Focal hypertrophy occurring with radiculopathies and mononeuropathies was associated with complex repetitive discharges (CRDs) in approximately half the cases. CRDs may play a role in the pathogenesis of myofiber hypertrophy by continuous myofiber stimulation, but in some cases, with and without CRDs, myofiber hypertrophy may be related to mechanical events. Muscle enlargement seen in old polio appears to involve a significant degree of pseudohypertrophy, although some myofiber hypertrophy occurs. The symmetrical occurrence of hypertrophy in genetically determined disorders, such as spinal muscular atrophy, and hereditary motor and sensory neuropathy types 1 and 2 may have both a genetic and a mechanical basis in addition to pseudohypertrophy in some cases.

Köbberling-Dunnigan syndrome: a rare cause of generalized muscular hypertrophy

A 36-year-old woman presented with muscle hypertrophy (particularly of the calves) since puberty, occasional muscle cramps, a musculine habitus, and a loss of subcutaneous fat on limbs and trunk sparing her face, neck, and vulva. Multiple lipomas were found on her trunk, and acanthosis nigricans on her neck. Laboratory testing revealed hyperlipidemia and pathological glucose tolerance with hyperinsulinemia. Physical and laboratory findings are consistent with Köbberling-Dunnigan syndrome, a rare inherited form of lipoatrophy. The patient's mother had the same body habitus and insulin-dependent diabetes mellitus. These cases suggest that partial lipodystrophy also affects muscle and is a cause of genuine muscular hypertrophy.

Neurogenic muscle hypertrophy in radiculopathy

The course of radiculopathy is sometimes associated with weakness and wasting of muscles. Very rarely in such cases, however, is hypertrophy of muscle fibres observed. Three cases are presented of sciatica with enlarged calves caused by hypertrophy of type 1 or types 1 and 2 muscle fibres. In light of the literature and the results obtained, an attempt is made to explain the cause of rare clinical symptoms and draw attention to diagnostic and therapeutic difficulties.

Isolated muscle hypertrophy as a sign of radicular or peripheral nerve injury

Images

Clinical and morphological study of calf enlargement following S-1 radiculopathy

Calf enlargement following sciatica is a rare condition. It is reported the case of a 28-year-old woman who complained of repeated episodes of lower back pain radiating into the left buttock and foot. One year after the beginning of her symptoms, she noticed enlargement of her left calf. X-ray studies disclosed L5-S1 disk degeneration. EMG showed muscle denervation with normal motor conduction velocity. Open biopsies of the gastrocnemius muscles were performed. The left gastrocnemius muscle showed hypertrophic type 2 fibers in comparison with the right gastrocnemius. Electron microscopy showed mildly increased number of mitochondria in these fibers. A satisfactory explanation for denervation hypertrophy has yet to be provided.