CURRENT Essentials of Critical Care.pdf

Chapter 13 Neurology 191■■■Critical Illness PolyneuropathyEssentials of Diagnosis• Flaccid weakness, loss of reflexes, sensory deficits indicatingperipheral neuropathy• Consider with weakness, failure to wean, decreased sensationin extremities• Up to 70% of sepsis or multiorgan failure, especially with prolongedICU stay• Distal axonopathy, degeneration of axons without inflammationdue to neuropathic consequence of decreased perfusion; no evidenceof nutritional deficiency, neuritis, drug effects• Nerve conduction studies: reduced muscle and sensory actionpotentials, fibrillations, loss of motor unit potentials with maximaleffort; no slowing of nerve conduction, conduction blocks,demyelinationDifferential Diagnosis• Guillain-Barré syndrome• Botulism• Myasthenia gravis• Prolonged effects of non-depolarizing muscle relaxants• Malnutrition• Paraneoplastic syndromes• Myopathies, including critical illness myopathy, corticosteroids,hypokalemiaTreatment• No specific treatment; correct underlying sepsis or organ failure;discontinue potentially neuropathic and myopathic medications(isoniazid, aminoglycosides, vincristine, corticosteroids);correct electrolyte abnormalities• Treat for vitamin deficiency (pyridoxine, thiamine)• Most have slow spontaneous improvement; recovery may belimited or absent if severe■ PearlCritical illness polyneuropathy should be considered in any patientwho is difficult to wean from mechanical ventilation.ReferenceHund E: Critical illness polyneuropathy. Curr Opin Neurol 2001;14:649.[PMID: 11562578]