Encephalitis Lethargica (von Economo's encephalitis)

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Background    Histopathology & Immunohistochemistry    Reference

BACKGROUND AND CLINICAL INFORMATION: Head

Clinical features:

• Fever, somolence, occulomotor palsies and signs of meningeal irritation.

• Freuquently occur in an epidemic form. Cases of post encephalitic Parkinson disease, often occur months to years after the encephalitis, followed a world pandemic of encephalitis lethargica between 1915 to 1927. Almost disappeared by 1930.

Anatomic locations: The brain stem adjacent to the aqueduct and the floor of the forth ventricle is the most frequently involved site. Also involve the gray matter of the cortex, basal ganglia, and the cervical spinal cord.

HISTOPATHOLOGY AND IMMUNOHISTOCHEMISTRY: Head

Perivascular infiltration by lymphocytes and plasma cells. Inflammatory changes were most severe in the midbrain. Degeneration of neurons is seen characteristically in the substantia nigra and in the occulomotor nuclei. For patients surviving more than 2 weeks, most of the neurons in substantia nigra are destroyed.

REFERENCES: Head