Acute Disseminated Encephalomyelitis (ADEM)

Acute Disseminated Encephalomyelitis (ADEM) is a rare condition that affects the brain and spinal cord, which are parts of the central nervous system. It usually happens after an infection or, less commonly, after a vaccination. The condition causes the body's immune system to mistakenly attack the protective covering of nerve fibers, called myelin, leading to inflammation. This inflammation can cause symptoms like sudden weakness, difficulty walking, confusion, and problems with vision or coordination. Because it affects the nervous system, it can impact movement, sensation, and thinking. The symptoms often develop quickly and can be severe but may improve with treatment.

Acute Disseminated Encephalomyelitis (ADEM) is an immune-mediated inflammatory demyelinating disorder of the central nervous system (CNS) characterized by widespread, multifocal lesions predominantly affecting the white matter. It typically follows a viral or bacterial infection or, rarely, vaccination, triggering an autoimmune response against myelin antigens. The pathophysiology involves perivenular inflammation and demyelination, leading to acute neurological deficits. Clinically, ADEM presents with encephalopathy, multifocal neurological signs, and rapid symptom onset. It is distinguished from multiple sclerosis by its monophasic course and often more diffuse CNS involvement. The condition is significant due to its potential for severe neurological impairment but generally has a favorable prognosis with appropriate immunotherapy.