Muscle hypertrophy of the lower leg caused by L5 radiculopathy

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.

Surgical Improvement of Neuropathy-Induced Calf Muscle Hypertrophy and Creatine Kinase Elevation: A Case Report

Peripheral neuropathy and radiculopathy often result in skeletal muscle disorders, typically leading to muscle atrophy. Concurrent muscle hypertrophy or persistently elevated creatine kinase (CK) is rare. While muscle hypertrophy is commonly observed in myogenic diseases, such as muscular dystrophy, acromegaly, inflammatory myopathies, and hypothyroidism, reports of muscle hypertrophy caused by neuropathy are infrequent. We encountered a patient with persistently elevated CK levels and unilateral lower leg muscle hypertrophy associated with neuropathy. The patient had cauda equina syndrome symptoms and pain in the left lower leg. Lumbar spine magnetic resonance imaging (MRI) revealed central spinal stenosis, which was believed to be the cause of the symptoms. Lower-limb MRI revealed high signal intensity in the gastrocnemius muscle on fat-suppressed T2-weighted imaging. Surgical treatment improved the radiculopathy, hypertrophy, and pain in the left lower leg. During the one-year follow-up, improvement was confirmed with both MRI and nerve conduction studies. Calf muscle hypertrophy associated with neuropathy has been reported; however, no reports have demonstrated pre- and postoperative changes with MRI and nerve conduction studies. We report a patient with lower leg muscle hypertrophy and persistent CK elevation associated with neuropathy, along with a literature review.

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.

Pitting Oedema in a Patient with Lumbar Disc Herniation: Case report of an unusual association

Oedema refers to the excessive accumulation of fluid within intercellular tissues as a result of disequilibrium between the capillary hydrostatic and oncotic pressure gradients. Lumbar disc herniation (LDH) commonly causes lower back pain and radicular leg pain. We report a 57-year-old female who presented to the neurosurgery clinic of the Bam University of Medical Sciences, Bam, Iran, in 2015 with pain and pitting oedema in the bilateral lower extremities. Magnetic resonance imaging confirmed a diagnosis of LDH of the L3-L4 and L4-L5 vertebrae. The patient subsequently underwent a bilateral laminotomy and foraminotomy of the involved vertebrae to relieve her pain. Following the surgery, there was a complete resolution of the LDH-related symptoms as well as the oedema. Although LDH has never before been associated with oedema, it may nevertheless cause lower limb oedema in exceptional and rare cases, as highlighted in this patient.

Calf pseudohipertrophy

Calf pseudohypertrophy due to radiculopathy is an exceptional phenomenon rarely described. We report a 67 year old woman with a previous history of lumbar disc surgery consulting by progressive increase for more than a year of evolution painless right calf associated loss of strength. Electromyographic findings showed chronic S1 radiculopathy and radiologically was appreciated in the medial gastrocnemius and soleus rights substitution of normal muscle tissue by adipose tissue without evidence of myopathy or sarcomatous degeneration.