Neurological complications of sepsis: critical illness polyneuropathy and myopathy

Sepsis may cause not only failure of parenchymal organs but can also cause damage to peripheral nerves and skeletal muscles. It is now recognized that sepsis-mediated disorders of the peripheral nerves and the muscle, called critical illness polyneuropathy (CIP) and critical illness myopathy, are responsible for weakness and muscle atrophy occurring de novo in intensively treated patients. CIP represents an acute axonal neuropathy that develops during treatment of severely ill patients and remits spontaneously, once the critical condition is under control. The course is monophasic and self-limiting. Among the critical illness myopathies, three main types have been identified: a nonnecrotizing "cachectic" myopathy (critical illness myopathy in the strict sense), a myopathy with selective loss of myosin filaments ("thick filament myopathy") and an acute necrotizing myopathy of intensive care. Clinical manifestations of both critical illness myopathies and CIP include delayed weaning from the respirator, muscle weakness, and prolonging of the mobilization phase. The pathogenesis of these neuromuscular complications of sepsis is not understood in detail but most authors assume that the inflammatory factors that mediate systemic inflammatory response and multiple organ failure are closely involved. In thick filament myopathy and acute necrotizing myopathy, administration of steroids and neuromuscular blocking agents may act as triggers. Specific therapies have not been discovered. Stabilization of the underlying critical condition and elimination of sepsis appear to be of major importance. Steroids and muscle relaxants should be avoided or administered at the lowest dose possible.