From the Research
Encephalitis lethargica should be treated with immunomodulatory therapies like corticosteroids, such as methylprednisolone 1g IV daily for 3-5 days, to reduce inflammation in acute cases, as supported by the most recent and highest quality study 1.
Clinical Features and Management
Encephalitis lethargica is a rare form of brain inflammation that causes severe neurological symptoms including excessive sleepiness, movement disorders, and psychiatric changes. This condition gained notoriety during an epidemic from 1917 to 1928, often called "sleeping sickness."
- The exact cause remains unclear, though it's believed to be autoimmune or post-infectious in nature, possibly triggered by the influenza virus 1.
- Some patients respond to levodopa-carbidopa (starting at 25/100mg three times daily) for parkinsonian symptoms that can develop 2.
- Antipsychotics may be needed for psychiatric manifestations, while supportive care including respiratory support is crucial for severely affected patients.
Diagnosis and Long-term Outcomes
Modern cases are extremely rare, making diagnosis challenging and often based on excluding other conditions through MRI, EEG, lumbar puncture, and comprehensive blood work 3.
- Long-term outcomes vary widely, with some patients developing post-encephalitic parkinsonism years after apparent recovery 4.
- The centennial lesson of encephalitis lethargica highlights the importance of understanding the organic basis of mental illness and the role of the substantia nigra in the pathophysiology of parkinsonism 4.
Key Considerations
- A study published in 2024 found that encephalitis lethargica has a distinct identity as a neuropsychiatric condition with a wide range of clinical features, and evidence for a relationship with infectious or occupational exposures was weak 1.
- The use of actual medical technology has provided growing evidence about autoimmune aetiology, which is gaining force 5.
- The optimal management of autoimmune encephalitis is still uncertain, but many patients with encephalitis are left with residual physical or neuropsychological deficits which require long-term multidisciplinary management 3.