Opsoclonus - Myoclonus syndrome induced by phenytoin intoxication

Movement disorders associated with antiseizure medications: A systematic review

New-onset movement disorders have been frequently reported in association with the use of antiseizure medications (ASMs). The frequency of specific motor manifestations and the spectrum of their semiology for various ASMs have not been well characterized. We carried out a systematic review of literature and conducted a search on CINAHL, Cochrane Library, EMBASE, MEDLINE, PsycINFO, and Scopus from inception to April 2021. We compiled the data for all currently available ASMs using the conventional terminology of movement disorders. Among 5123 manuscripts identified by the search, 437 met the inclusion criteria. The largest number of reports of abnormal movements were in association with phenobarbital, valproic acid, lacosamide, and perampanel, and predominantly included tremor and ataxia. The majority of attempted interventions for all agents were discontinuation of the offending drug or dose reduction which led to the resolution of symptoms in most patients. Familiarity with the movement disorder phenomenology previously encountered in relation with specific ASMs facilitates early recognition of adverse effects and timely institution of targeted interventions.

Postintervention acute opsoclonus myoclonus syndrome

Opsoclonus myoclonus syndrome (OMS) is a rare, neurological condition affecting 1 in 10 000 000 people annually. Opsoclonus, defined as involuntary rapid, multivectorial oscillations of the eyes, together with ataxia and myoclonus are usually present. OMS may be paraneoplastic: often associated with occult neuroblastoma in childhood and with breast carcinoma or small cell lung carcinoma in adults. Other aetiologies include viral or toxic agents. The pathogenesis is thought to be immune mediated. A 37-year-old woman with previous inflammatory cranial mononeuropathies was admitted for elective dilatation and curettage (D&C). Immediately after she complained of left-sided paraesthesia and later became disoriented, with incoherent speech, inability to obey commands, opsoclonus of the eyes and myoclonic jerks. Investigations including onconeuronal antibodies, cerebrospinal fluid analysis, and imaging were normal. She was treated with intravenous methylprednisolone with rapid improvement. Previous surgeries with anaesthesia were uncomplicated. The anaesthetic agents used for the D&C were fentanyl and propofol.