Morvan's syndrome: clinical, laboratory, and in vitro electrophysiological studies

Anesthetic Management of Patients With Morvan Syndrome: A Case Report and Literature Review

Morvan syndrome is a rare condition distinguished by hyperactivity within the central, autonomic, and peripheral nervous systems. Due to the limited number of cases, this presents clinical challenges stemming from the scarcity of published literature. We present a successful anesthetic approach for a patient diagnosed with Morvan syndrome scheduled for elective major intra-thoracic surgery to remove metastases from a thymoma. The patient had previously undergone thymectomy, with the syndrome being diagnosed only one year after the surgery. Additionally, we conducted a literature review on the anesthetic management of this condition.

A case report of Morvan syndrome

Authors describe the case of a 22-year-old Caucasian male who presented acutely with psychomotor agitation, insomnia and muscle twitching with painful cramps. Autonomic symptoms were as well present, with profuse sweating, blood pressure fluctuations and tachycardia. He presented a miliary rash in his left forearm as well as in the neck. Electromyography documented myokymic movements bilaterally at both gastrocnemii and pretibial muscles. Brain imaging had no abnormalities, and anti-LGI1 and anti-CASPR2 resulted positive; this data together with electrophysiological findings suggested a Morvan syndrome. High-dose steroid therapy and plasma exchange improved substantially the clinical picture of the patient.

Total Wake: Natural, Pathological, and Experimental Limits to Sleep Reduction

Sleep is not considered a pathological state, but it consumes a third of conscious human life. This share is much more than most optimistic life extension forecasts that biotechnologies or experimental and medical interventions can offer. Are there insurmountable physical or biological limitations to reducing the duration of sleep? How far can it be avoided without fatal consequences? What means can reduce the length of sleep? It is widely accepted that sleep is necessary for long-term survival. Here we review the limited yet intriguing evidence that is not consistent with this notion. We concentrate on clinical cases of complete and partial loss of sleep and on human mutations that result in a short sleep phenotype. These observations are supported by new animal studies and are discussed from the perspective of sleep evolution. Two separate hypotheses suggest distinct approaches for remodeling our sleep machinery. If sleep serves an unidentified vital physiological function, this indispensable function has to be identified before “sleep prosthesis” (technical, biological, or chemical) can be developed. If sleep has no vital function, but rather represents a timing mechanism for adaptive inactivity, sleep could be reduced by forging the sleep generation system itself, with no adverse effects.

Morvan's syndrome with anti contactin associated protein like 2 - voltage gated potassium channel antibody presenting with syndrome of inappropriate antidiuretic hormone secretion

Morvan's syndrome is a rare autoimmune disorder characterized by triad of peripheral nerve hyperexcitability, autonomic dysfunction, and central nervous system symptoms. Antibodies against contactin-associated protein-like 2 (CASPR2), a subtype of voltage-gated potassium channel (VGKC) complex, are found in a significant proportion of patients with Morvan's syndrome and are thought to play a key role in peripheral as well as central clinical manifestations. We report a patient of Morvan's syndrome with positive CASPR2–anti-VGKC antibody having syndrome of inappropriate antidiuretic hormone as a cause of persistent hyponatremia.

The role of the laboratory in the expanding field of neuroimmunology: Autoantibodies to neural targets

Accelerated identification of autoantibodies associated with previously idiopathic neurological disease has provided insights into disease mechanisms, enhanced understanding of neurological function, and opportunities for improved therapeutic interventions. The role of the laboratory in the expanding field of neuroimmunology is critical as specific autoantibody identification provides guidance to clinicians in diagnosis, prognosis, tumor search strategies, and therapeutic interventions. The number of specific autoantibodies identified continues to increase and newer testing strategies increase efficiencies in the laboratory and availability to clinicians. The need for broadly targeted efficient testing is underscored by the variability in clinical presentation and tumor associations attributable to a specific autoantibody, and conversely the various autoantibody specificities that can be the cause of a given clinical presentation. While many of the antineural antibodies were first recognized in the setting of neoplastic disease, idiopathic autoimmune neurological disease in the absence of underlying tumor is increasingly recognized. Appropriation of therapeutic modalities used to treat autoimmune disease to treat these autoantibody mediated neurological diseases has improved patient outcomes. Interaction between clinicians and laboratorians is critical to our understanding of these diseases and optimization of the clinical benefits of our increasing knowledge in neuroimmunology.

Morvan Syndrome: A Case Report With Patient Narrative and Video

A 74-year-old gentleman was admitted to the regional neurosciences center with encephalopathy, myokymia, and dysautonomia. Chest imaging had previously identified an incidental mass in the anterior mediastinum, consistent with a primary thymic tumor. Antivoltage-gated potassium channel (anti-VGKC) antibodies were positive (titer 1273 pmol/L) and he was hypokalemic. Electromyogram and nerve conduction studies were in keeping with peripheral nerve hyperexcitability syndrome, and an electroencephalogram was consistent with encephalopathy. A diagnosis of Morvan syndrome was made, for which he was initially treated with high-dose steroids, followed by a 5-day course of intravenous immunoglobulin (IVIG) therapy. He also underwent thymectomy, followed by a postexcision flare of his symptoms requiring intensive care management. Further steroids, plasmapheresis, and IVIG achieved stabilization of his clinical condition, enabling transfer for inpatient neurorehabilitation. He was commenced on azathioprine and a prolonged oral steroid taper. A subsequent presumed incipient relapse responded well to further IVIG treatment. This case report documents a thymoma-associated presentation of anti-VGKC-positive Morvan syndrome supplemented by patient and carer narrative and video, both of which provide valuable further insights into this rare disorder. There are a limited number of publications surrounding this rare condition available in the English literature. This, combined with the heterogenous presentation, association with underlying malignancy, response to treatment, and prognosis, provides a diagnostic challenge. However, the association with anti-VGKC antibody-associated complexes and 2 recent case series have provided some scope for both accurate diagnosis and management.

Isaacs syndrome: A review

Isaacs syndrome is a peripheral nerve hyperexcitability (PNH) syndrome that presents as continuous motor activity. Clinical findings include cramps, fasciculations, and myokymia. Electrodiagnosis plays a key role in diagnosis by demonstrating after-discharges on nerve conduction studies, and fasciculation potentials, myokymic discharges, neuromyotonic discharges, and other types of abnormal spontaneous activity on needle examination. Etiopathogenesis involves the interaction of genetic, autoimmune, and paraneoplastic factors, which requires a broad-ranging evaluation for underlying causes. Initial treatment is symptomatic, but immune therapy is often needed and can be effective. The purpose of this review is to describe the syndrome and its pathogenesis, assist the reader in evaluating patients with suspected Isaacs syndrome and distinguishing it from other disorders of PNH, and suggest an approach to management, including both symptomatic and immunomodulating therapy.

Clinical, laboratory and electrophysiological features of Morvan's fibrillary chorea

Morvan's Fibrillary Chorea (MFC) is a rare autoimmune disorder causally associated with auto-antibodies directed at the voltage-gated potassium channel (VGKC-Abs). It classically presents with sleep disturbances, neuromyotonia and dysautonomia. We aimed to systematically characterise the features of MFC by describing a patient and reviewing published literature. Case notes of 27 patients with MFC (one from our clinic and 26 from the literature) were reviewed and clinical data were extracted and analysed. We found that MFC mainly affects men (96%) and runs a subacute course over months. Neoplasia (56%), VGKC-Abs positivity (79%) and autoimmunity (41%) are frequent associations. Myokymia, insomnia and hyperhidrosis were almost universally described. Other autonomic features were present in 63% with the most common being cardiovascular and bowel disturbances. Clinical, radiological or electroencephalographical features of limbic encephalitis were present in 19% of patients. Outcome was fair with an overall recovery rate of 78%. All patients with malignancies underwent surgery. Immunotherapies including corticosteroids, intravenous immunoglobulins and plasma exchange were instituted in 22 patients and 19 (86%) responded. Of all symptomatic treatments tried, carbamazepine, phenytoin, sodium valproate, levetiracetam and niaprazine were found to be effective. The broad clinical spectrum of VGKC-Abs diseases can make early recognition of MFC difficult. Myokymia, insomnia and hyperhidrosis are invariably present. There may be abnormalities on cerebrospinal fluid testing and VGKC-Abs can occasionally be absent. Early initiation of immunotherapies and malignancy screening are important to prevent adverse outcomes in a condition that generally responds favourably to treatment.

Morvan syndrome: a case report and review of the literature

Morvan syndrome is characterized by central, autonomic, and peripheral hyperactivity. Examples of central hyperactivity include confusion, memory problems, hallucinations, insomnia, and myoclonus; examples of autonomic hyperactivity include hyperhidrosis and fluctuations in blood pressure; examples of peripheral hyperreactivity include clinical or electrophysiological evidence of painful cramps, myokymia, and neuromyotonia. We present a typical case of Morvan syndrome and the first detailed review of the clinical and therapeutic literature of all 27 cases from the English language literature. Morvan syndrome is considered to be an autoimmune disorder and antibodies against voltage-gated potassium channels are found in most cases. Oral immunomodulatory therapy, intravenous immunoglobulin, and plasmapharesis may be entertained. Thymoma is found in approximately 50% of cases and thymectomy may be curative as in our particular case.

Needle electromyography: basic concepts and patterns of abnormalities

Needle electromyography (EMG) records electrical signals generated from muscle fibers and interprets the signals to characterize underlying pathologic changes that are occurring in motor units within muscles. Different types of spontaneously firing waveforms and motor unit potential changes occur with different neuromuscular disorders. The performance of reliable EMG studies depends on the technical skills of the physician in inserting, moving, recording with a needle electrode, and analyzing electric signals recorded from muscle. This article reviews the technique of needle EMG and recognition and interpretation of various EMG waveforms. The author presents several demonstrative videos at www.neurologic.theclinics.com.

Fluctuating neuromuscular transmission defects and inverse acetazolamide response in episodic ataxia type 2 associated with the novel CaV2.1 single amino acid substitution R2090Q

We report on a 51-year-old woman with episodic ataxia type 2 (EA2) and a novel CaV2.1 C-terminal single amino acid substitution (R2090Q). She had a 4-year history of acute episodes with ataxia, hemihypesthesia and hemicrania. Furthermore, fluctuating neuromuscular transmission abnormalities rarely described in patients with EA2 were clinically and electrophysiologically documented in this patient. Upon initiation of acetazolamide treatment she experienced a dose-dependent severe increase of attack frequency and severity along with a shorter attack duration, while she responded well to subsequent therapy with 4-aminopyridine.

Needle electromyography

Physiologic assessment of diseases of the motor unit from the anterior horn cells to the muscles relies on a combination of needle electromyography (EMG) and nerve conduction studies (NCS). Both require a unique combination of knowledge of peripheral nervous system anatomy, physiology, pathophysiology, diseases, techniques, and electricity is necessary. Successful, high-quality, reproducible EMG depends on the skills of a clinician in patient interaction during the physical insertion and movement of the needle while recording the electrical signals. These must be combined with the skill of analyzing electric signals recorded from muscle by auditory pattern recognition and semiquantitation.1052 This monograph reviews the techniques of needle EMG and waveform analysis and describes the types of EMG waveforms recorded during needle EMG.

Paraneoplastic neurological syndromes: a review

BACKGROUND

Paraneoplastic neurologic syndromes (PNS) constitute a rare group of disorders resulting from damage to the nervous system in the setting of cancer physically unrelated to the tumor site. PNS are believed to result from an autoimmune attack of normal neuronal tissue, spurred by similar neuronal antigens ectopically expressed by tumor cells.

REVIEW SUMMARY

The most common PNS are reviewed and also their association with specific onconeural antibodies, some directly pathogenic, others whose role in the disease process is less clear-cut. This diversity in pathogenesis is likely due to the relative role of humoral versus cellular immunity in PNS. Virtually any cancer may result in PNS but certain tumors, small cell lung cancer, gynecologic cancers (breast and ovarian), thymoma, and plasma cell tumors are more frequently encountered. In most instances, immunosuppressive therapy is unhelpful and outcome is poor.

CONCLUSIONS

PNS have diverse presentations, affecting both the central and peripheral nervous system and commonly, it is the PNS, not cancer that is the presenting symptom. Only subsequently, after onconeural antibodies are discovered or cancer is found, is PNS diagnosed. Neurologists should familiarize themselves with these rare syndromes and treatment principles, as rapid detection and treatment of the underlying tumor offer the best chance for recovery or prevention of further neurologic deterioration.