Status Dystonicus as the Initial Manifestation of Subacute Sclerosing Panencephalitis: Lessons in Early Recognition

Dear Editor, Subacute sclerosing panencephalitis (SSPE) is a progressive measles-related encephalitis classically characterized by cognitive decline and periodic myoclonus. However, atypical movement disorder presentations may obscure diagnosis and delay appropriate evaluation. Here, we report an adolescent with SSPE presenting as status dystonicus, highlighting an important diagnostic challenge in pediatric movement disorder practice. A 15-year-old partially immunized boy presented with a 3-month history of progressive behavioral disturbance, including agitation, emotional lability, and persecutory ideation, initially managed as a primary psychiatric disorder. He subsequently developed language regression, gait difficulty, and orofacial dyskinesias, evolving into generalized dystonia involving axial, cervical, and upper limb musculature. On admission, he was severely undernourished, mute, incontinent, and bed-bound. Examination revealed persistent dystonic posturing, facial grimacing, generalized hypertonia with preserved deep tendon reflexes, bilateral flexor plantar responses, and intermittent autonomic instability (bradycardia with tachycardia episodes). Continuous severe dystonia with autonomic instability requiring benzodiazepine sedation fulfilled criteria for status dystonicus. Magnetic resonance imaging suggested encephalitis, and autoimmune encephalitis was initially suspected. Pulse methylprednisolone and symptomatic anti-dystonia therapy (levodopa, trihexyphenidyl, and baclofen) produced no significant response. Recurrent dystonic storms were aborted with intravenous lorazepam. Following partial control of dystonia, intermittent myoclonic jerks became apparent. Electroencephalography demonstrated generalized, bilaterally synchronous periodic epileptiform discharges occurring at approximately 4–5 s intervals with background slowing, consistent with classical SSPE periodic complexes. Cerebrospinal fluid (CSF) analysis revealed elevated anti-measles immunoglobulin G (IgG) antibodies (20 U/mL; positive >11 U/mL) with negative immunoglobulin M. Serum measles IgG was also positive. The diagnosis fulfilled Dyken’s criteria based on characteristic clinical features, typical periodic electroencephalography (EEG) findings, and raised CSF measles antibody titers. Dystonia overall has been reported in approximately 10%–15% of SSPE cohorts[1]; however, it is rarely the presenting manifestation compared to classical myoclonus, reported in up to 90% of cases. Multiple Indian case reports have described status dystonicus or prominent dystonia as an early feature.[2,3] In measles-endemic regions, such atypical hyperkinetic presentations may be under-recognized due to overlap with autoimmune encephalitis and primary movement disorders, contributing to diagnostic delay. Status dystonicus may represent a rare but fulminant initial manifestation of SSPE, particularly in unimmunized children from endemic regions. In adolescents presenting with refractory dystonia and subacute behavioral change, early EEG evaluation and prompt CSF measles antibody testing are essential—even in the absence of classical myoclonus. This case reinforces the need to include SSPE in the differential diagnosis of unexplained dystonic storms in pediatric practice. Acknowledgements The authors acknowledge the patient and his family for consenting to the publication of this report. Author contributions SPP: Clinical management, data collection, and manuscript drafting. MG: Conceptualization, clinical management, data collection, manuscript drafting, literature review, and final approval of manuscript. Author note This case was previously presented as an oral presentation at the 5th State Chapter Conference of the Association of Family Physicians of India (AFPI) held on 2-3 August 2025 in Bangalore, Karnataka. The manuscript has not been published previously and is not under consideration elsewhere. Consent to participate Informed consent was obtained from the patient’s legal guardian for participation and publication. Patient consent form The authors certify that they have obtained all appropriate patient consent forms. The patient’s guardian has given consent for clinical information to be reported. The patient’s identity has been adequately anonymized. Ethical approval and Institutional Review Board statement As this is a single-case report, formal Institutional Ethics Committee approval was not required as per institutional policy. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.