Autonomic hyperreflexia.

Autonomic hyperreflexia presents as acute episodes of uninhibited reflex sympathetic hyperactivity in the patient with chronic high spinal cord lesion. An understanding of the pathophysiology of this syndrome is paramount in its successful management. It occurs in patients with chronic spinal cord lesions above T7 upon stimulation below the lesion, particularly distention of the urinary bladder. The main clinical signs are paroxysmal hypertension and bradycardia. Management of acute episodes should include withdrawal of the initiating stimulus and possibly administration of pharmacological agents such as nifedipine and nitroprusside. Long-term treatment may involve radical surgery. Despite its technical difficulties, spinal block is still the anesthesia of choice in these patients.