Clinical conundrum: status epilepticus culminating into acute dystonia myoclonus

Movement Disorders in Patients with Subacute Sclerosing Panencephalitis: A Systematic Review

BACKGROUND

Subacute sclerosing panencephalitis (SSPE) is a complication of measles, occurring after a latency of 4-10 years. It continues to occur in developing countries although resurgence is being reported from developed countries. Characteristic features include progressive neuropsychiatric issues, myoclonus, seizures, movement disorders and visual impairment. Electroencephalography (EEG) typically shows periodic generalized discharges, and elevated CSF anti-measles antibodies are diagnostic. Movement disorders are being increasingly recognized as part of the clinical spectrum, and range from hyperkinetic (chorea, dystonia, tremor, tics) to hypokinetic (parkinsonism) disorders and ataxia.

OBJECTIVES

This article aims to comprehensively review the spectrum of movement disorders associated with SSPE.

METHODS

A literature search was conducted in PubMed and EMBASE databases in December 2023 and articles were identified for review.

RESULTS

Movement disorders reported in SSPE included hyperkinetic (chorea, dystonia, tremor and tics), hypokinetic (parkinsonism), ataxia and extraocular movement disorders. Myoclonus, a core clinical feature, was the most frequent "abnormal movement." Movement disorders were observed in all clinical stages, and could also be a presenting feature, even sans myoclonus. Hyperkinetic movement disorders were more common than hypokinetic movement disorders. An evolution of movement disorders was observed, with ataxia, chorea and dystonia occurring earlier, and parkinsonism later in the disease. Neuroradiological correlates of movement disorders remained unclear.

CONCLUSION

A wide spectrum of movement disorders was observed throughout the clinical stages of SSPE. Most data were derived from case reports and small case series. Multicentric longitudinal studies are required to better delineate the spectrum and evolution of movement disorders in SSPE.

Spectrum of Movement Disorders Among Children With Subacute Sclerosing Panencephalitis: A Cross-Sectional Study

Background: Subacute sclerosing panencephalitis is a progressive devastating condition due to persistence of mutant measles virus, affecting children and adolescents, characterised by myoclonus, seizures, and neuropsychiatric issues. Movement disorders apart from myoclonus are reportedly uncommon. We aimed to describe frequency and proportion of movement disorders among children with subacute sclerosing panencephalitis, hypothesizing that these occur more frequently than previously reported. Methods: In this cross-sectional study, we enrolled children with subacute sclerosing panencephalitis between 1 month and 18 years of age who fulfilled the diagnosis of subacute sclerosing panencephalitis as per modified Dyken criteria, and examined them for movement disorders. We also assessed their clinical profile and disease severity via Jabbour staging and modified Rankin Scale score. We compared demographic, clinical, and laboratory features of children with and without movement disorders. Results: We enrolled 50 children (36 males; 72%) (age range 1.5-14 years). Of these, 28 (56%) had movement disorders. Among movement disorders, the most frequent was myoclonus (92%), followed by ataxia (9; 18%), chorea-athetosis (7; 14%), dystonia (6; 12%), tremor (4; 8%), repetitive behavior (4; 8%), and parkinsonism (3; 6%). Movement disorders were the presenting feature of subacute sclerosing panencephalitis among 7 children. There were no significant differences in clinical or laboratory features among children with and without movement disorders. Conclusions: Movement disorders were frequent in subacute sclerosing panencephalitis. Hyperkinetic disorders were dominant. Dystonia and chorea-athetosis occurred more commonly among nonmyoclonus movement disorders. Movement disorders may manifest even in earlier stages of subacute sclerosing panencephalitis and may be the heralding feature. Recognition of these features is important to plan management and reduce morbidity.