Panencephalitis is a rare and severe neurological condition that affects the brain cells and causes inflammation. Some synonyms for panencephalitis include progressive rubella panencephalitis, panencephalitis subacute sclerosing, and Dawson encephalitis. Other related terms are SSPE, which stands for subacute sclerosing panencephalitis, and measles encephalitis, which is a complication of the measles virus. These terms all refer to similar conditions that have similar symptoms and effects on the brain. While these conditions are rare, they can have devastating effects on the patient's health and quality of life. Early detection, diagnosis, and treatment are critical for managing these conditions.