The Autonomic Storm

This chapter focuses on the diagnosis and management of autonomic storm that occurs after a severe brain injury. The diagnosis of autonomic storm is based on the recognition of the regular pattern of dysautonomic spells in a patient with acute intracranial disease. It must be distinguished from other syndromes that have features of autonomic instability-such as neuroleptic malignant syndrome-malignant hyperthermia, and lethal catatonia. Lethal catatonia is most often seen in patients with psychiatric disorders but can also occur after viral encephalitis. Morphine sulfate, bromocriptine, and nonselective β-blockers-such as labetalol or propranolol-have been successfully used to treat autonomic storms. These agents may be used alone or in combination, especially during the acute phase. Once dysautonomic manifestations have been under control for several weeks, the medications may be tapered while carefully watching for symptom recurrence. Often, it is necessary to continue treatment for several months. The mechanisms by which opioids, dopamine (DA) agonists, and β-blockers improve dysautonomia remain speculative. Antiepileptic drugs are typically not helpful in true cases of autonomic storm but should be tried if questions about a possible epileptic nature of the spells persist. Systematic studies of different treatment regimens are needed to optimize outcome in patients with autonomic storm.