A previously healthy 35-year-old man is evaluated in the hospital for new-onset fever. He was admitted 9 days ago following a motorcycle collision that resulted in severe traumatic brain injury and multiple extremity fractures. The patient initially required mechanical ventilation and multiple interventions to lower his intracranial pressure. He has since stabilized and underwent fracture fixation and tracheostomy, with subsequent weaning off of mechanical ventilation. Yesterday, while receiving a sponge bath, the patient was noted to be diaphoretic as well as hypertensive and tachycardic; his symptoms improved after morphine administration. Today, during routine repositioning and vital sign measurement, he again becomes diaphoretic. Temperature is 38.8 C (101.8 F), blood pressure is 194/110 mm Hg, pulse is 146/min, and respirations are 40/min. Oxygen saturation is 98% on room air. On examination, heart sounds and lung sounds are normal. Neurologic examination shows eye opening and withdrawal of all 4 extremities in response to painful stimuli, which is unchanged from previous examinations. Which of the following is the most likely cause of this patient's abnormal vital signs?

Question

A previously healthy 35-year-old man is evaluated in the hospital for new-onset fever.  He was admitted 9 days ago following a motorcycle collision that resulted in severe traumatic brain injury and multiple extremity fractures.  The patient initially required mechanical ventilation and multiple interventions to lower his intracranial pressure.  He has since stabilized and underwent fracture fixation and tracheostomy, with subsequent weaning off of mechanical ventilation.  Yesterday, while receiving a sponge bath, the patient was noted to be diaphoretic as well as hypertensive and tachycardic; his symptoms improved after morphine administration.  Today, during routine repositioning and vital sign measurement, he again becomes diaphoretic.  Temperature is 38.8 C (101.8 F), blood pressure is 194/110 mm Hg, pulse is 146/min, and respirations are 40/min.  Oxygen saturation is 98% on room air.  On examination, heart sounds and lung sounds are normal.  Neurologic examination shows eye opening and withdrawal of all 4 extremities in response to painful stimuli, which is unchanged from previous examinations.  Which of the following is the most likely cause of this patient's abnormal vital signs?

Quizplus · Accepted Answer

This patient with severe traumatic brain injury and episodic hypertension, tachycardia, and diaphoresis most likely has paroxysmal sympathetic hyperactivity (PSH), a clinical syndrome characterized by sudden episodes of excessive sympathetic activity. PSH occurs in approximately 10%-20% of patients with severe traumatic brain injury. Although its pathophysiology is not fully understood, PSH likely occurs following damage to cortical areas that are responsible for modulating and inhibiting lower sympathetic centers (eg, in the hypothalamus, brainstem, and spinal cord). The resulting sympathetic hyperactivity most commonly manifests as rapid-onset episodes of tachycardia, hypertension, and tachypnea often accompanied by fever and diaphoresis. These episodes, which can last up to 20-30 minutes, are usually triggered by external stimuli (eg, bathing, repositioning) but may occur spontaneously. PSH is a clinical diagnosis with no confirmatory tests. Treatment consists of supportive care (eg, avoiding triggers, treating fever) and medication (eg, opioids, GABA-agonists, α₂-agonists) to abort and/or prevent episodes. Opioids may improve symptoms via a general reduction of sympathetic tone. (Choice A) Sudden cessation of alcohol intake (eg, hospitalization) may lead to severe alcohol withdrawal (eg, delirium tremens), with rebound central nervous system overexcitation causing autonomic hyperactivity. However, withdrawal symptoms typically persist for days (rather than short episodes) and have an earlier onset (eg, within 2-3 days after the last drink). (Choice B) Bacterial sepsis can cause fever, diaphoresis, and tachycardia; however, it is more likely to cause hypotension (eg, septic shock) than severe hypertension. In addition, episodes would be unlikely to improve with morphine administration and would likely worsen (eg, progress to septic shock) over the course of a day if not treated appropriately with antibiotics. (Choice C) Severe elevation of intracranial pressure can cause hypertension; however, hypertension is classically accompanied by bradycardia and irregular respirations (ie, Cushing triad). (Choice E) Pulmonary thromboembolism can cause tachypnea and tachycardia. However, it usually causes accompanying hypoxia. In addition, it is more likely to cause hypotension (from decreased preload) than severe hypertension, and fever >38 C (>100.4 F) is uncommon. (Choice F) Uncontrolled acute pain can cause episodic tachycardia, hypertension, and tachypnea, which may improve with morphine administration. However, vital sign changes are typically less extreme, and fever is uncommon. Educational objective: Traumatic brain injury can cause damage to cortical areas responsible for inhibiting lower sympathetic centers. This disrupted inhibition may result in paroxysmal sympathetic hyperactivity, a syndrome characterized by rapid-onset episodes of tachycardia, hypertension, and tachypnea often accompanied by fever and diaphoresis. References: Understanding paroxysmal sympathetic hyperactivity after traumatic brain injury. (http://www.ncbi.nlm.nih.gov/pubmed/25506508) Paroxysmal sympathetic hyperactivity: the storm after acute brain injury. (http://www.ncbi.nlm.nih.gov/pubmed/28816118) Paroxysmal sympathetic hyperactivity after acute brain injury. (http://www.ncbi.nlm.nih.gov/pubmed/23780802)

A Previously Healthy 35-Year-Old Man Is Evaluated in the Hospital