What is the primary underlying pathology of Guillain-Barré syndrome?

The primary underlying pathology of Guillain-Barré syndrome is the demyelination of peripheral motor nerves. This condition is classified as an autoimmune disorder in which the body’s immune system mistakenly attacks the myelin sheath—the protective covering surrounding the peripheral nerves. This demyelination leads to disrupted nerve conduction, resulting in muscle weakness, paralysis, and sensory changes.

In Guillain-Barré syndrome, the descending weakness often follows a viral or bacterial infection, which can trigger the immune response. The loss of myelin contributes to the characteristic symptoms of the syndrome, such as areflexia, symmetrical weakness, and the potential for respiratory compromise, depending on the extent of nerve involvement.

Understanding this pathology is crucial for clinical diagnosis and treatment, as it differentiates Guillain-Barré syndrome from other neurological conditions that may present with similar symptoms but have different underlying mechanisms, such as diseases impacting the central nervous system or other forms of neuropathy.