The Extracranial Consequences of Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) is managed across the full spectrum of healthcare, from clinical diagnosis to management of the hemorrhage and associated complications. Knowledge of the pathogenesis and pathophysiology of SAH is widely known; however, a full understanding of the underlying molecular, cellular, and circulatory dynamics has still to be achieved. Intracranial complications including delayed ischemic neurologic deficit (vasospasm), rebleed, and hydrocephalus form the targets for initial management. However, the extracranial consequences including hypertension, hyponatremia, and cardiopulmonary abnormalities can frequently arise during the management phase and have shown to directly affect clinical outcome. This review will provide an update on the pathophysiology of SAH, including the intra- and extracranial consequences, with a particular focus on the extracranial consequences of SAH.

We review the literature and provide a comprehensive update on the extracranial consequences of SAH that we hope will help the management of these cohort of patients.

In addition to the pathophysiology of SAH, the following complications were examined and discussed: vasospasm, seizures, rebleed, hydrocephalus, fever, anemia, hypertension, hypotension, hyperglycemia, hyponatremia, hypernatremia, cardiac abnormalities, pulmonary edema, venous thromboembolism, gastric ulceration, nosocomial infection, bloodstream infection/sepsis, and iatrogenic complications.

Although the intracranial complications of SAH can take priority in the initial management, the extracranial complications should be monitored for and recognized as early as possible because these complications can develop at varying times throughout the course of the condition. Therefore, a variety of investigations, as described by this article, should be undertaken on admission to maximize early recognition of any of the extracranial consequences. Furthermore, because the extracranial complications have a direct effect on clinical outcome and can lead to and exacerbate the intracranial complications, monitoring, recognizing, and managing these complications in parallel with the intracranial complications is important and would allow optimization of the patient's management and thus help improve their overall outcome.