Acute respiratory failure neuropathy: a variant of critical illness polyneuropathy.

Objective: To describe a severe axonal polyneuropathy that follows acute respiratory failure and, in turn, causes continued ventilator dependence and paralysis after resolution of the primary illness.

Design: Retrospective chart review of three patients and prospective analysis of two patients.

Setting: Respiratory and neurologic ICUs of a general hospital.

Patients: Five critically ill patients after an episode of acute respiratory failure. Neuromuscular blocking drugs were used in four patients, intermittently in two patients, high doses of corticosteroids were briefly administered in four, four patients had multiple organ failure, three patients had sepsis, but weakness preceded these complications in two patients.

Interventions: None.

Main Results: All patients had moderate-to-severe limb weakness with reduced or absent reflexes. Sensation was relatively preserved and the spinal fluid protein concentrations were normal. Electrophysiologic studies showed a severe, acute axonal motor neuropathy in four patients and normal studies in the fifth that later demonstrated denervation. Sensory potentials were mildly or not affected. Two quadriparetic patients died at 2.5 months, one remained weak and ventilator dependent several months after onset, and two patients recovered to walk in 4 to 6 months.

Conclusions: Severe axonal motor neuropathy after acute respiratory failure probably represents a variant of "critical illness polyneuropathy" that can be recognized from the temporal course of a conversion from primarily pulmonary to a pattern of neuromuscular ventilatory failure.