Subacute Sclerosing Panencephalitis

SSPE (Dawson encephalitis) is a rare progressive dementia of children/adolescents caused by measles virus/variant. Insidious onset, subacute/chronic progression, fatal. Schilder (1924) first described; Dawson (1933) found inclusions; 1965 EM showed paramyxovirus-like particles and high anti-measles antibody in CSF/serum; 1969 measles virus cultured from brain cells.

Common Symptoms

Coma; forgetfulness; circulatory failure; cognitive decline; ataxia; myoclonus; hyperreflexia

Causes and Pathogenesis

(1) Etiology: chronic measles infection; defective virus persists due to host immune dysregulation. High anti-measles antibody in serum/CSF; measles antigen in cortex; intranuclear inclusions on EM; virus recovered in half of co-cultures; animal transmissibility. (2) Pathogenesis: mutant/defective measles virus cannot be cleared. Matrix (M)/fusion (F)/hemagglutinin (H) proteins are defective → impaired budding/release → intracellular accumulation. Alternatively, immune defect allows latency. Early-life (especially <1 year) measles predisposes. M-mRNA translation defect causes M-protein-deficient persistent virus; spreads by nucleocapsid transfer. Pathology: diffuse brain atrophy, firm to touch; perivascular lymphocyte/macrophage/plasma cell cuffs; cortical neuronal loss; patchy demyelination and gliosis (sclerosing encephalitis); eosinophilic intranuclear/intracytoplasmic inclusions; EM shows hollow paramyxovirus-like tubules; fluorescent antibody positive for measles. Inclusions common early; late cases show more demyelination.

Treatment

Drug therapy, symptomatic, supportive therapy

Preventive Measures

Measles vaccination is the most effective prevention; rates have dropped since live-attenuated vaccine. Routine immunization of neonates/children; early comprehensive treatment to reduce complications and prolong survival.

Department to Visit

It is recommended to visit the Infectious Diseases department; an appointment can be booked on this platform before the visit.

Warm reminder: The above information is for health science reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek medical attention at a regular hospital promptly.