Flapping Tremor: Unraveling Asterixis-A Narrative Review

Drug-Induced Myoclonus: A Systematic Review

Background and Objectives: Myoclonus is already associated with a wide variety of drugs and systemic conditions. As new components are discovered, more drugs are suspected of causing this disabling abnormal involuntary movement. This systematic review aims to assess the medications associated with drug-induced myoclonus (DIM). Materials and Methods: Two reviewers assessed the PubMed database using the search term "myoclonus", without language restriction, for articles published between 1955 and 2024. The medications found were divided into classes and sub-classes, and the subclasses were graded according to their level of evidence. Results: From 12,097 results, 1115 were found to be DIM. The subclasses of medications with level A evidence were intravenous anesthetics (etomidate), cephalosporins (ceftazidime, cefepime), fluoroquinolones (ciprofloxacin), selective serotonin reuptake inhibitors (citalopram, escitalopram, paroxetine, sertraline), tricyclic antidepressant (amitriptyline), glutamate antagonist (amantadine), atypical antipsychotics (clozapine, quetiapine), antiseizure medications (carbamazepine, oxcarbazepine, phenytoin, gabapentin, pregabalin, valproate), pure opioid agonist (fentanyl, morphine), bismuth salts, and mood stabilizers (lithium). The single medication with the highest number of reports was etomidate. Drug-induced asterixis is associated with a specific list of medications. The neurotransmitters likely involved in DIM are serotonin, dopamine, gamma-aminobutyric acid (GABA), and glutamate. Conclusions: DIM may be reversible with management that can include drug discontinuation, dose adjustment, and the prescription of a medication used to treat idiopathic myoclonus. Based on the main clinical constellation of symptoms and pathophysiological mechanisms found in this study, DIM can be categorized into three types: type 1 (serotonin syndrome), type 2 (non-serotonin syndrome), and type 3 (unknown).

Meningeal Dissemination and Drop Metastasis From Glioma Presenting With Non-Epileptic Myoclonus and Minipolymyoclonus

We describe the case of a 36-year-old woman with a past medical history of low grade right frontal lobe glioma and focal epilepsy presenting with subacute, progressive, multifocal myoclonus and neck and back pain. Unlike her typical seizures, the myoclonus exhibited a distinct semiology, involving both positive and negative muscle jerks affecting multiple limb muscles while sparing the face. In addition, neurological examination revealed low-amplitude, arrhythmic movements of the hands and fingers, resembling minipolymyoclonus. There were no other neurological exam findings, including mental status changes, extrapyramidal signs or signs of myelopathy. Brain and spine MRI indicated leptomeningeal and spinal "drop" enhancing lesions, suggesting likely malignant evolution of the glioma. EEG ruled out a cortical origin of the myoclonus. Pharmacological trials with benzodiazepines and other antiepileptic medications were ineffective. The patient's myoclonus was most likely spinal segmental in origin from meningeal spread of glioma. The spinal roots or anterior horns of the spinal cord may have represented a focus of hyperexcitability responsible for generating minipolymyoclonus. Our case expands the etiological spectrum of non-epileptic myoclonus and minipolymyoclonus to encompass meningeal carcinomatosis and drop metastases from glioma. These cases may occur even without overt signs of myelopathy. Recognizing such presentations holds significance due to the poor prognosis associated with meningeal spread of glioma and the limited response of non-epileptic myoclonus to symptomatic treatments.