Propriospinal myoclonus due to cervical disc herniation. Case report

Spinal segmental myoclonus following spinal surgery

A 44-year-old male was admitted with L5/S1 spondylodiscitis complicated by a posterior epidural abscess that was compressing the thecal sac with severe narrowing of the canal and compression of the cauda equine. He underwent computed tomography (CT) guided drainage followed by L5/S1 decompression laminectomy and was started on a 6-week course of intravenous antibiotics with good response. He remained well and afebrile with inflammatory markers showing improvement. During this period, he developed intermittent myoclonic movements of right lower limb with severe pain over the back radiating to the gluteal region which hindered his rehabilitation potential. He was diagnosed with spinal segmental myoclonus based on clinical findings and history of recent spinal surgery. He was successfully treated with a course of clonazepam and continues to make functional improvements during his rehabilitation program.

Surgical Treatment of Propriospinal Myoclonus: A Case Report

Propriospinal myoclonus (PSM) is a rare segmental movement disorder characterized by repetitive irregular myoclonic jerks of the trunk and/or axial limbs at the resting state. It is imperative to make a correct diagnosis as other movement disorders can be mistaken for or mask PSM. Therefore, a battery of neuroimaging and neurophysiological testing must be undertaken. In our case report, we discuss a patient who was diagnosed with PSM concurrently with cervical degenerative stenosis and then had a successful outcome via surgical decompression and arthrodesis of the cervical spine. We documented the patient’s postoperative course and achievement of complete remission, sustained at a 41-month follow-up. We then grouped our case together with five other PSM cases in the literature to offer readers a broader context of the role of surgical spinal intervention in ameliorating PSM.

A Case of Cervical Radiculopathy Presenting as Dystonic Tremor

BACKGROUND

To our knowledge, this is the first case report of a cervical disc prolapse and foraminal stenosis presenting with dystonic tremor in addition to brachialgia.

CASE DESCRIPTION

A 54-year-old, right-handed man presented with a dystonic tremor and aching throughout his right upper limb. Magnetic resonance imaging of the cervical spine revealed a disc osteophyte complex at C5/6 causing C6 foraminal impingement bilaterally in addition to a disc osteophyte complex at C6/C7 causing severe bilateral foraminal narrowing. Electromyography showed neurogenic changes consistent with chronic C6/7 radiculopathy. There was no response to numerous medical treatments for his dystonia or brachialgia. Computed tomography-guided right C6 and C7 root block led to complete but temporary resolution of all symptoms, including the dystonic tremor. Definitive treatment consisting of a C5/6 and C6/7 anterior cervical discectomy and fusion led to a complete, immediate, and continued resolution of his right-sided brachialgia and dystonic tremor.

CONCLUSIONS

This case highlights the potential of cervical disc prolapse to present with dystonic tremor with the likely mechanism being secondary to the painful radiculopathy and highlights the potential benefits of surgical decompression with this atypical presentation.

Diagnostic Criteria, Differential Diagnosis, and Treatment of Minor Motor Activity and Less Well-Known Movement Disorders of Sleep

Purpose of review

Sleep-related movement disorders (SRMD) include several different motor activities during sleep. Few of them are well known and well classified, whereas others are minor motor disorders of sleep which are neither thoroughly characterized and classified nor have been extensively investigated to clarify their pathogenesis and clinical relevance. This review will focus on those minor sleep-related movement disorders.

Recent findings

Before diagnosing periodic limb movement (PLM) disorder in patients with PLM during polysomnography, other disorders associated with PLM need to be excluded, namely restless legs syndrome (RLS), narcolepsy, REM sleep behavior disorder (RBD), and sleep-related breathing disorder. For the diagnosis of propriospinal myoclonus at sleep-onset, multi-channel surface electromyography recording during polysomnography is required and a possible psychogenic origin of the movement disorder has to be considered. Excessive fragmentary myoclonus (EFM) does not require symptomatic treatment, but further evaluation is suggested as electrophysiological abnormalities are present in 50% of cases. Nine percent of healthy sleepers meet the criteria for EFM, raising the question if current, arbitrarily defined, cutoffs are valid. Hypnagogic foot tremor, rhythmic feet movements, alternating leg muscle activation, and high-frequency leg movements are somewhat overlapping minor motor activities during sleep which may exist on their own or represent stereotyped movements to relieve RLS-like symptoms. Neck myoclonus is probably a physiological phenomenon related to REM twitching. RBD is formally a parasomnia but a relevant differential diagnosis when evaluating sleep-related movement disorders. In particular, prodromal RBD is characterized by electromyographic and behavioral findings on video-polysomnography which needs to be differentiated by minor sleep-related movement disorders.

Summary

Minor SRMD beyond the well-known main motor disorders of sleep should be correctly diagnosed, distinguished from differential diagnosis, and understood in their potential clinical relevance, in order also to start an appropriate treatment if needed.

Spinal myoclonus: a rare presentation of cervical myelopathy

Myoclonus describes a movement disorder characterised by brief, abrupt and involuntary contractions of muscles or groups of muscles, usually associated with intracranial lesions, with limited evidence linking it to spinal pathologies. The pathophysiology of spinal myoclonus is extensive and multifactorial. Infection, intramedullary and extramedullary space-occupying lesions, trauma, vascular abnormalities, degenerative processes and cervical spondylosis have been implicated with the disease, the latter been associated with cervical stenosis with no reported cases linking it to an underlying cervical disc herniation. Although medical therapy with clonazepam, levetiracetam, valproate, tetrabenazine hydrochloride and spinal block injections has been equivocal, spinal myoclonus secondary to disc herniation requires surgical intervention. This report describes a case of segmental spinal myoclonus, secondary to a herniated cervical intervertebral disc. After corpectomy and a cage-augmented fusion technique, the myoclonic symptoms resolved. To our knowledge, this was the first report to describe the successful management of discogenic spinal myoclonus with spinal surgery.

Propriospinal myoclonus: clinical reappraisal and review of literature

OBJECTIVE

Propriospinal myoclonus (PSM) is a rare disorder with repetitive, usually flexor arrhythmic brief jerks of the trunk, hips, and knees in a fixed pattern. It has a presumed generation in the spinal cord and diagnosis depends on characteristic features at polymyography. Recently, a historical paradigm shift took place as PSM has been reported to be a functional (or psychogenic) movement disorder (FMD) in most patients. This review aims to characterize the clinical features, etiology, electrophysiologic features, and treatment outcomes of PSM.

METHODS

Re-evaluation of all published PSM cases and systematic scoring of clinical and electrophysiologic characteristics in all published cases since 1991.

RESULTS

Of the 179 identified patients with PSM (55% male), the mean age at onset was 43 years (range 6-88 years). FMD was diagnosed in 104 (58%) cases. In 12 cases (26% of reported secondary cases, 7% of total cases), a structural spinal cord lesion was found. Clonazepam and botulinum toxin may be effective in reducing jerks.

CONCLUSIONS

FMD is more frequent than previously assumed. Structural lesions reported to underlie PSM are scarce. Based on our clinical experience and the reviewed literature, we recommend polymyography to assess recruitment variability combined with a Bereitschaftspotential recording in all cases.

Propriospinal Myoclonus Induced by a Herniated Lumbar Intervertebral Disc at a Young Age: A Case Report

The cause of propriospinal myoclonus (PSM) is idiopathic. Cervical trauma, ischemic myelopathy secondary to a spinal dural arteriovenous fistula, syringomyelia, Lyme neuroborreliosis, human immunodeficiency virus central nervous system infection, and cervical disc herniation can be the cause of PSM, but lumbar herniated intervertebral disc (HIVD) induced PSM has not been reported. We describe a patient who presented with PSM induced by HIVD and was treated with an epidural steroid injection using a transforaminal approach.

Reversible propriospinal myoclonus due to thoracic disc herniation: long-term follow-up

PSM is a rare form of myoclonus of spinal origin. The thoracic level is considered as the myoclonic generator in most cases; however, structural abnormality in conventional magnetic resonance imaging (MRI) related to PSM is more rare. We report the case of a 23-year-old man with PSM with ventral thoracic disc herniation confirmed by conventional MRI, which completely resolved after thoracic discectomy. This case indicates that decompressive surgery might be a valid treatment option.

Spinal myoclonus after spinal cord injury

BACKGROUND/OBJECTIVE

In the course of examining spinal motor function in many hundreds of people with traumatic spinal cord injury, we encountered 6 individuals who developed involuntary and rhythmic contractions in muscles of their legs. Although there are many reports of unusual muscle activation patterns associated with different forms of myoclonus, we believe that certain aspects of the patterns seen with these 6 subjects have not been previously reported. These patterns share many features with those associated with a spinal central pattern generator for walking.

METHODS

Subjects in this case series had a history of chronic injury to the cervical spinal cord, resulting in either complete (ASIA A; n = 4) or incomplete (ASIA D; n = 2) quadriplegia. We used multi-channel electromyography recordings of trunk and leg muscles of each subject to document muscle activation patterns associated with different postures and as influenced by a variety of sensory stimuli.

RESULTS

Involuntary contractions spanned multiple leg muscles bilaterally, sometimes including weak abdominal contractions. Contractions were smooth and graded and were highly reproducible in rate for a given subject (contraction rates were 0.3-0.5 Hz). These movements did not resemble the brief rapid contractions (ie, "jerks") ascribed to some forms of spinal myoclonus. For all subjects, the onset of involuntary muscle contraction was dependent upon hip angle; contractions did not occur unless the hips (and knees) were extended (ie, subjects were supine). In the 4 ASIA A subjects, contractions occurred simultaneously in all muscles (agonists and antagonists) bilaterally. In sharp contrast, contractions in the 2 ASIA D subjects were reciprocal between agonists and antagonists within a limb and alternated between limbs, such that movements in these 2 subjects looked just like repetitive stepping. Finally, each of the 6 subjects had a distinct pathology of their spinal cord, nerve roots, distal trunk, or thigh; in 4 of these subjects, treatment of the pathology eliminated the involuntary movements.

CONCLUSION

The timing, distribution, and reliance upon hip angle suggest that these movement patterns reflect some elements of a central pattern generator for stepping. Emergence of these movements in persons with chronic spinal cord injury is extremely rare and appears to depend upon a combination of the more rostrally placed injury and a pathologic process leading to a further enhancement of excitability in the caudal spinal cord.