Snapshot A 45-year-old woman presents to the emergency room with a stiff neck, photophobia, and an extremely severe headache that began while she was enjoying a glass of sweet Alabama southern tea. She states her symptoms came on immediately and she is in severe distress. Introduction Commonly caused by ruptured aneurysm (Berry Aneurysm) most common site of berry aneurysm development is the anterior communicating artery (AComm) stroke AVM trauma Blood accumulates between arachnoid and pia mater Presentation Symptoms intense headache neck stiffness fever nausea vomiting fluctuating level of conciousness possibly seizures can resemble meningitis because both cause menigeal irritation Physical exam Berry aneurysm presents with severe, sudden headache and CN III palsy Evaluation Immediate head CT without contrast to look for blood in the subarachnoid space If CT is negative, and there is no papilledema or focal signs, proceed with an LP RBC in CSF CSF xanthoma (CSF protein > 150 mg/dL or serum bilirubin > 6 mg/dL) Differential Hemorrhagic stroke, trauma, meningitis, and migraine headache. Treatment Once an SAH has been confirmed, move to four vessel angiography. Surgical or IR clipping or coiling of aneurysm or AVM Focus on preventing elevation of ICP by: raising the head of the bed limiting fluids treating hypertension giving calcium channel blockers (nimodipine) Prophylax with anti-seizure medictions (phenytoin). Nimodipine to prevent vasospasm Prognosis, Prevention, and Complications Rebleeds, extension into brain parenchyma, and arterial spasms are complications. Also at risk of communicating hydrocephalus due to injury to the arachnoid villi and cisterns Patients with aneurysmal subarachnoid hemorrhage are at risk for developing hyponatremia