Encephalitis lethargica is a rare neurological condition that primarily affects the brain, leading to inflammation. It was first identified during the Spanish flu pandemic in the early 20th century. Symptoms can include extreme sleepiness, fever, and changes in behavior. Some patients may experience movement disorders or difficulty with coordination. The exact cause of encephalitis lethargica is not fully understood, but it is believed to be linked to viral infections. Treatment focuses on managing symptoms, as there is no specific cure. Some individuals may recover completely, while others can experience long-term effects, including cognitive and motor difficulties.