Encephalitis lethargica

What it is

A rare brain inflammatory disease characterized by acute or subacute encephalitis with involvement of the midbrain and basal ganglia occurring in children as well as adults. Initial symptoms are pharyngitis and fever, followed by progressive lethargy, sleep disturbances, extrapyramidal symptoms (parkinsonism, chorea, dystonia), neuropsychiatric manifestations (obsessive-compulsive behavior, mutism, catatonia), and ocular features (oculogyric crises). Autoantibodies against human basal ganglia are often positive. Survivors may develop post-encephalitic syndromes, most prominently parkinsonism.

Key facts

Prevalence

<1 / 1 000 000 (Europe)

Age of onset

Adult

Inheritance

Not applicable

Classified as

Disease

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Cross-references