Encephalitis lethargica (von Economo disease)
Association of clinic pharyngitis followed by sleep disorder, basal ganglia signs (particularly Parkinsonism), neuropsychiatric sequelae and MRI swelling in the basal ganglia and the substantia nigra is very suggestive of Encephalitis lethargica. It is a rare disease, first described by von Economo in 1916 during an epidemic, affecting 500,000 people worldwide in 1916-1927. There has been no further epidemic of EL reported since the 1920s although sporadic cases have been described.
Alternative diagnoses were excluded with the help of multiple immunohistochemistry test in LCR. Infectious/inflammatory laboratory and serological workup were normal. Furthermore a scan of the chest, abdomen, and pelvis was normal. Intrathecal oligoclonal bands (OCB) were found.
Sparing of the insular and basifrontal regions rule out confounding diagnosis.
Steroid and immunomodulating therapy were administered with a beneficial effect. There were only mild neuropsychiatric symptoms and Parkinsonism sequelae.