Clinical, physiologic, and pathologic evidence for vagus dysfunction in a case of traumatic brain injury.

A trauma victim with locked-in syndrome demonstrated severely decreased bowel sounds, intact response to suppository, and elevated, but unchanging pulse. Absent cardiac response to tracheal suctioning, high gastric residual volumes, and pulmonary edema in response to a urecholine challenge demonstrated dysfunction in the automatic system. Symptoms persisted for 2 1/2 years until death. At autopsy, asymmetric bilateral involvement of the dorsal motor nucleus of the vagus and of the nerve tract in the medulla were demonstrated. In contrast, a control subject with locked-in syndrome caused by a stroke did not demonstrate these phenomena. In trauma patients with delayed gastric emptying, measurement of the heart rate response to deep suctioning may lead to the diagnosis of this vagus dysfunction syndrome.