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Review
. 2025 Jun:92:138-151.
doi: 10.1016/j.ajem.2025.03.024. Epub 2025 Mar 15.

High risk and low incidence diseases: Aneurysmal subarachnoid hemorrhage

Christian R Gerhart  1 , Aaron J Lacy  2 , Brit Long  3 , Alex Koyfman  4 , Charles E Kircher  5
Affiliations
Review

High risk and low incidence diseases: Aneurysmal subarachnoid hemorrhage

Christian R Gerhart et al. Am J Emerg Med. 2025 Jun.

Abstract

Introduction: Aneurysmal subarachnoid hemorrhage (aSAH) is a serious condition that carries a high rate of morbidity.

Objective: This review highlights the pearls and pitfalls of aSAH, including presentation, diagnosis, and management in the emergency department based on current evidence.

Discussion: aSAH is a type of hemorrhagic stroke, most commonly from rupture of a saccular aneurysm, which results in leakage of blood into the subarachnoid space. It presents acutely and has many mimics, making the diagnosis difficult. Patients who present with either sentinel or acute presentation of a headache that is described as sudden or severe, has associated neck stiffness, cranial nerve deficits, syncope, seizure, and/or coma should raise suspicion for the diagnosis. Non-contrast head computed tomography is the imaging modality of choice for evaluation and diagnosis of the disease in patients who present acutely. Further diagnostic testing with lumbar puncture or advanced neuroimaging may be required in patients who present >6 h after symptom onset. Patients with aSAH require critical, multidisciplinary care, with particular attention to management of airway, breathing, and circulation; expeditious referral for neurosurgical intervention; coagulopathy reversal; and prophylaxis against downstream complications.

Conclusion: An understanding of aSAH can assist emergency clinicians in diagnosing and managing this disease.

Keywords: Aneurysm; Headache; Intracranial hemorrhage; Neurologic deficit; Neurology; Ottawa SAH rule; SAH; Stroke; Subarachnoid hemorrhage; Vascular.

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Conflict of interest statement

Declaration of competing interest None. No AI Program was utilized in the construction of this manuscript.

Figures

Fig. 1.
Fig. 1.
Circle of Willis anatomy with common saccular aneurysm locations. Figure adapted from https://commons.wikimedia.org/wiki/File:Circle_of_Willis_unlabeled.svg.
Fig. 2.
Fig. 2.
Subhyaloid bleeding (Terson Syndrome) in a patient with intracranial hemorrhage. Obtained from Ophthalmic Atlas Images by EyeRounds.org from https://webeye.ophth.uiowa.edu/eyeforum/atlas/pages/Terson/index.htm#gsc.tab=0. Accessed December 1, 2024.
Fig. 3.
Fig. 3.
Slice of NCHCT demonstrating subarachnoid hemorrhage, noted by high-attenuation in the subarachnoid space. Figure from https://commons.wikimedia.org/wiki/File:SAB_basal_bei_Aneurysma.jpg. Accessed December 1, 2024.
See this image and copyright information in PMC

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