Encephalitis lethargica

Editor-In-Chief: Prab R Tumpati, MD
Obesity, Sleep & Internal medicine
Founder, WikiMD Wellnesspedia &
W8MD's medical weight loss NYC, sleep center NYC
Philadelphia medical weight loss and Philadelphia sleep clinics

Encephalitis lethargica
Synonyms	N/A
Pronounce	N/A
Specialty	N/A
Symptoms	High fever, headache, lethargy, double vision, delayed physical and mental response, sleep inversion
Complications	Parkinsonism, catatonia, coma
Onset	Acute
Duration	Variable
Types	N/A
Causes	Unknown, possibly viral infection
Risks	Unknown
Diagnosis	Clinical diagnosis, neuroimaging, lumbar puncture
Differential diagnosis	Influenza, meningitis, encephalitis, narcolepsy
Prevention	N/A
Treatment	Supportive care, antiviral drugs, corticosteroids
Medication	N/A
Prognosis	Variable, can lead to chronic illness
Frequency	Rare
Deaths	Historical epidemic in the 1920s

A mysterious neurological disease

Encephalitis lethargica, also known as sleepy sickness, is a rare and mysterious neurological disease that was first identified in the early 20th century. It is characterized by high fever, headache, double vision, delayed physical and mental response, and lethargy. The disease can lead to a state of coma-like sleep, and in some cases, it can result in long-term neurological damage or death.

History

The first recorded outbreak of encephalitis lethargica occurred in 1916, and it spread worldwide, affecting millions of people. The disease reached epidemic proportions between 1917 and 1928. The cause of the epidemic remains unknown, and it disappeared as mysteriously as it appeared.

Symptoms

The symptoms of encephalitis lethargica can vary widely among individuals. Common symptoms include:

• High fever
• Severe headache
• Lethargy and prolonged sleepiness
• Double vision
• Delayed physical and mental responses
• Muscle pain and weakness
• Behavioral changes

In severe cases, patients may enter a coma-like state, and some may experience Parkinsonism or other long-term neurological sequelae.

Pathophysiology

The exact cause of encephalitis lethargica is unknown, but it is believed to be related to an autoimmune response triggered by an infection. Some researchers have suggested a link to the influenza virus, but this has not been conclusively proven. The disease primarily affects the brain, particularly the midbrain and diencephalon, leading to the characteristic symptoms.

Diagnosis

Diagnosis of encephalitis lethargica is challenging due to its rarity and the lack of specific diagnostic tests. It is primarily based on clinical presentation and the exclusion of other conditions. Magnetic resonance imaging (MRI) and computed tomography (CT) scans may be used to rule out other causes of encephalitis.

Treatment

There is no specific treatment for encephalitis lethargica. Management focuses on alleviating symptoms and providing supportive care. Corticosteroids and other immunosuppressive therapies may be used to reduce inflammation. In cases with Parkinsonian symptoms, dopaminergic medications may be beneficial.

Prognosis

The prognosis for encephalitis lethargica varies. Some patients recover fully, while others may experience long-term neurological complications. The disease can be fatal in severe cases.

See also

• Encephalitis
• Parkinsonism
• Autoimmune disease
• Influenza