D Guillain-barré syndrome
Definition
Guillain-Barré syndrome refers to acquired inflammatory peripheral neuropathies that are characterized by: (1) acute onset, (2) elevated cerebrospinal fluid (CSF) protein levels with low CSF cell counts (cyto-albumologic dissociation), and (3) a monophasic illness with at least partial recovery. Guillain-Barré syndrome is subdivided into acute inflammatory demyelinating polyneuropathy, acute motor and sensory axonal neuropathy, acute motor axonal neuropathy, and Miller Fisher syndrome.
Pathophysiology
Acute inflammatory demyelinating polyneuropathy, the demyelinating form, accounts for up to 97% of cases of Guillain-Barré syndrome in North America and Europe. It is a sporadic disorder with an incidence of 0.6 to 1.9 cases per 100,000 in North America and Europe. Men are more likely to be affected than women (2:1).
Central nervous system bulbar involvement is most frequently manifested as bilateral facial paralysis. The most common symptoms are difficulty in swallowing because of pharyngeal muscle weakness and impaired ventilation resulting from intercostal muscle paralysis. Lower motor neuron involvement gives way to flaccid paralysis, and corresponding tendon reflexes are diminished. Sensory disturbances occur as paresthesias in the distal extremities and generally precede the onset of paralysis. Pain occurs in different forms, such as headache, backache, or tenderness to deep pressure. Wide fluctuations in blood pressure (orthostatic), abnormalities on electrocardiogram (e.g., conduction disturbances, tachycardia), diaphoresis, peripheral vasoconstriction, and thromboembolism may be seen as a result of autonomic nervous system dysfunction. Complete recovery can occur within weeks when “segmental” demyelination in the CNS is the primary pathologic change. A mortality rate of 3% to 8% is the result of sepsis, respiratory distress syndrome, and pulmonary embolism.