High risk and low incidence diseases: Aneurysmal subarachnoid hemorrhage

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.