C. Take the patient's blood pressure.
Autonomic dysreflexia is a massive, uncompensated cardiovascular reaction mediated by the sympathetic nervous system. Manifestations include hypertension (up to 300 mm Hg systolic), throbbing headache, marked diaphoresis above the level of the injury, bradycardia (30 to 40 beats/min), piloerection, flushing of the skin above the level of the injury, blurred vision or spots in the visual fields, nasal congestion, anxiety, and nausea. It is important to measure blood pressure when a patient with a spinal cord injury complains of headache. Other nursing interventions in this serious emergency are elevation of the head of the bed 45 degrees or sitting the patient upright, notification of the physician, and assessment to determine the cause. Table 61-8 lists the causes and symptoms of autonomic dysreflexia. The nurse must monitor blood pressure frequently during the episode. An α-adrenergic blocker or an arteriolar vasodilator may be administered.