English

Abstract

Introduction Aneurysm subarachnoid haemorrhage is a leading cause of mortality occurring in about 10 per 100,000 persons annually. It is characterised by three commonly occurring complaints: ‘worst headache of my life’, photophobia and meningismus. It is imperative that emergency department and primary care physicians understand how to diagnose and initially manage aneurysm subarachnoid haemorrhage. Discussion This review details cerebrospinal fluid analysis and the current imaging techniques for identifying aneurysm subarachnoid haemorrhage and intracranial aneurysms. It will cover the initial management and treatment options along with considerations in delayed SAH presentation. Conclusion A high suspicion for SAH during the initial evaluation increases the patient’s chance for early intervention and reduces mortality and disability. Introduction Aneurysm subarachnoid haemorrhage (SAH) is a leading cause of mortality (40%–50% of SAH), occurring in about 10 per 100,000 persons annually; 30,000 SAH in the United States alone each year. SAH is characterised by three commonly occurring complaints: ‘worst headache of my life’, photophobia and meningismus. These symptoms often can be confused with bacterial or viral meningitis and migraine headaches. As a result, aneurysm SAH is initially misdiagnosed in nearly 12% of patients, a potentially lethal mistake. Misdiagnosis increases the risk of re-bleeding and subsequent death1. The rule of thirds dictates that one-third of the patients with SAH die before reaching the hospital, another third present with irrecoverable neurological deficits and the last third make it to treatment; half of the last third will have long-term disabilities (Figure 1)2. In short, only about 16% of patients will be left with minimal or no permanent neurological sequelae after SAH. A high suspicion for SAH during the initial evaluation in the Emergency Department or by the Primary Care Physician increases the patient’s chance for early intervention and reduces mortality and disability. Standardised protocols for the evaluation of patients with ‘headache’ in the Emergency Department currently does not exist, further complicating the initial evaluation and disposition of these patients; such a protocol may save lives. Here, we review the diagnosis and initial management of suspected aneurysm in patients with SAH. Discussion Aetiology Trauma is the most common cause of SAH, followed by ruptured intracranial aneurysm (75%–80%) and arteriovenous malformations (4%–5%). Other causes to consider include: central nervous system vasculitis, cerebral artery dissection, coagulopathy, dural venous sinus thrombosis, spinal cord arteriovenous malformation or dural fistula, sickle cell disease and sympathomimetic drugs such as cocaine. In 14%–22% of SAH, no cause can be identified on angiography even with multiple modes of imaging. In this case, the aetiology may be from a venous bleed (perimesencephalic haemorrhage) or small aneurysm that auto-thrombosed and no longer fills with blood; this is referred to as angiographic negative SAH3. Patients with SAH who are suspected of having a ruptured aneurysm should be evaluated for risk factors associated with brain aneurysm formation, a spinal tap to look for blood in the cerebrospinal fluid and radiographic imaging. Risk Factors Many risk factors for brain aneurysm formation and haemorrhage are modifiable with medication or behavioural changes; cigarette smoking and hypertension being the most important (Table 1)4. Identification of risk factors in men and women aged 18–49 years concluded that SAH in this age group is mostly associated with cigarette smoking, illicit drug use and hypertension5. A 70%–75% of patients with SAH had a prior history of smoking and 50%–60% are current smokers. Other independent risk factors in this study included a low Body Mass Index, family history of haemorrhagic stroke, and low educational achievement; the increased risk of SAH persists even after cessation of cigarette smoking6. The odds ratio (OR) of SAH in previous smokers (OR, 4.1; 95% confidence interval (CI): 2.7–6.0) and current smokers (OR, 5.4; 95% CI: 3.7–7.8) suggests that the haemodynamic, but not structural changes induced by smoking, may resolve after smoking cessation6. Genome linkage studies observing 104 siblings affected with intracranial * Corresponding author Email: deshaiee@upstate.edu Department of Neurosurgery, SUNY Upstate Medical University, Syracuse, NY, USA