Myoclonus- A Review

Myoclonus, Uremia, and Delirium in a Liver Transplant Recipient: A Case Report and Literature Review

BACKGROUND

Consultation-liaison (CL) psychiatrists are frequently asked to consult on various abnormal movements(1). CL psychiatrists can be instrumental in aiding the primary teams to identify and manage these movement disorders. In this manuscript, we provide an illustrative case of a patient presenting with myoclonus and offer a review on this important topic. Myoclonus accompanied by delirium represents a rare post-transplant complication and can be associated with heightened morbidity and mortality. The incidence of this complication in solid organ transplant (SOT) recipients is scarcely documented, and its pathophysiology remains inadequately understood. Potential etiologies in the intensive care unit (ICU) are numerous and likely multifactorial. The literature lacks detailed descriptions of the correlation and association between myoclonus and uremia. Management of this condition requires a multimodal approach, focusing on resolving underlying metabolic disturbances and providing symptomatic treatment.

OBJECTIVES

This manuscript describes the clinical presentation of myoclonus in a liver transplant recipient accompanied by delirium and precipitated by uremia. We aim to highlight the diagnostic and therapeutic complexities, help providers distinguish myoclonus from other movement disorders, and aid appropriate management.

METHODS AND RESULTS

We present a case of acute myoclonus in an elderly female liver transplant recipient precipitated by uremia and improved after continuous renal replacement treatment. In addition, we conducted a systematic review utilizing EMBASSE and PubMed of reported cases of myoclonus, delirium, and/or encephalopathy accompanied by uremia. We included 12 manuscripts in our review and discussed their findings.

CONCLUSION

CL psychiatrists are frequently consulted for a range of movement disorders in the ICU, including myoclonus. Accurate diagnosis and identification of contributing etiologies are critical in these cases. Management typically involves addressing the underlying disorder, such as using dialysis for uremia, alongside symptomatic treatment with benzodiazepines to mitigate the frequency and amplitude of myoclonus. This approach helps to alleviate both the physical burden and psychological distress associated with the condition. This case underscores the pivotal role of the CL psychiatrist within a complex multidisciplinary team, contributing to diagnostic precision and optimization of management strategies for movement disorders.

Detecting negative myoclonus during long-term home measurements using wearables

OBJECTIVE

The aim of this study was to develop a feasible method for the detection of negative myoclonus (NM) through long-term home measurements in patients with progressive myoclonus epilepsy type 1.

METHODS

The number and duration of silent periods (SP) associated with NM were detected during a 48 h home recording using wearable surface electromyography (EMG) sensors.

RESULTS

A newly developed algorithm was able to find short (50-69 ms), intermediate (70-100 ms), and long (101- 500 ms) SPs from EMG data. Negative myoclonus assessed by the algorithm correlated significantly with the video-recorded and physician-evaluated unified myoclonus rating scale (UMRS) scores of NM and action myoclonus. Silent period duration, number, and their combination, correlated strongly and significantly also with the Singer score, which assesses functional status and ambulation.

CONCLUSIONS

Negative myoclonus can be determined objectively using long-term EMG measurements in home environment. With long-term measurements, we can acquire more reliable quantified information about NM as a symptom, compared to short evaluation at the clinic.

SIGNIFICANCE

As measured using SPs, NM may be a clinically useful measure for monitoring disease progression or assessing antimyoclonic drug effects objectively.

A Case of Drug-Resistant Myoclonus Improved by Only Slight Adjustment to the Hemodialysis Setting

Myoclonus, a rare complication in patients with end-stage renal disease, is typically ameliorated through hemodialysis. The present case concerns an 84-year-old male with chronic renal failure undergoing hemodialysis, presenting involuntary movements in his limbs, which gradually worsened from the initiation of hemodialysis without constant elevation of serum blood urea nitrogen and electrolytes levels. Surface electromyography revealed characteristic findings consistent with myoclonus. He was diagnosed with subcortical-nonsegmental myoclonus related to hemodialysis, and the myoclonus was significantly alleviated after slightly increasing the post-dialysis target weight even though drug treatment was ineffective. This case suggests that drug-resistant myoclonus in patients with renal failure may be improved by adjusting hemodialysis settings, even in cases of atypical dialysis disequilibrium syndrome.

Assessment and Treatment of Myoclonus: A Review

Myoclonus is defined as sudden, brief, shock-like contractions of muscles, and it can be a challenging diagnosis for the clinician to face. The number of aetiologies can make it difficult to determine the appropriate diagnostic workup for each individual patient without ordering a broad array of diagnostic studies from the start. As with other neurological conditions, a comprehensive history and physical examination are paramount in generating and ordering the initial differential diagnosis. Neurophysiological classification of myoclonus, using both electroencephalogram and electromyography, can be very helpful in elucidating the underlying aetiology. Treatment of myoclonus is often symptomatic, unless a clear treatable underlying cause can be found. This article aims to help providers navigate the assessment and treatment of myoclonus, focusing on neurophysiological classification as a guide. By the end of this article, providers should have a good understanding of how to approach the workup and treatment of myoclonus of various aetiologies.