Demyelinerade

Demyelinerade refers to the loss or damage of the myelin sheath surrounding nerve fibers, a condition that disrupts fast electrical signaling. Myelin surrounds axons and is produced by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system.

Common causes include autoimmune demyelinating diseases such as multiple sclerosis and neuromyelitis optica; inflammatory or infectious processes; metabolic or nutritional deficiencies such as vitamin B12 deficiency; toxic exposures; genetic disorders like leukodystrophies; and physical trauma.

The loss of myelin slows nerve conduction, may cause conduction block and sensory or motor deficits, and can lead to neurodegeneration if axons are damaged. Remyelination can occur, especially in the peripheral nervous system, but is often incomplete and may leave deficits or scar tissue.

Symptoms depend on the affected pathways and can include numbness, tingling, weakness, coordination problems, vision disturbances, fatigue, pain, or sensory loss. In central nervous system demyelination, episodes may be intermittent; in chronic conditions, progression may occur.

Diagnosis involves magnetic resonance imaging to detect demyelinating lesions, along with clinical history and exam. Additional tests may include lumbar puncture, nerve conduction studies, and blood tests to identify underlying causes. Treatment targets the underlying condition, reduces inflammation, protects neurons, or manages symptoms; disease-modifying therapies are used for autoimmune demyelination, steroids for acute attacks, and rehabilitation.

Prognosis varies with cause, extent of demyelination, and patient factors. Some conditions stabilize or improve with remyelination in part, while others progress with accumulating axonal loss.