Chronic Inflammatory Demyelinating Polyneuropathy

CIDP is an acquired demyelinating disorder of the peripheral nervous system in which the body's immune system mistakenly attacks the myelin covering of peripheral nerves. Pathologically, this results in demyelination, axonal degeneration, and inflammation of the peripheral nerves. The exact trigger is unknown but may involve molecular mimicry following infections, genetic predisposition, and dysregulation of B cells and T cells that target myelin proteins. CIDP exists in several clinical variants including typical CIDP (most common with distal-predominant weakness), atypical CIDP subtypes, and demyelinating forms that resemble other neuropathies. Symptoms develop over weeks to months and then either progress continuously or follow a relapsing-remitting course. Patients experience progressive distal weakness that often becomes proximal, sensory loss, and gait disturbance. Diagnosis requires characteristic clinical features combined with supportive electrodiagnostic studies showing demyelination, elevated CSF protein, and exclusion of other demyelinating diseases. Disease severity varies widely, from mild sensory involvement to severe disability requiring assistive devices. About 60% of patients respond well to first-line immunotherapies including corticosteroids, intravenous immunoglobulin (IVIG), and plasmapheresis, though response rates and long-term outcomes vary.