Review Question - QID 218493

This patient with a history of hypertension, smoking, and Ehlers-Danlos syndrome who presents with a sudden onset headache, photophobia, and nuchal rigidity most likely has a subarachnoid hemorrhage (SAH). The diagnosis is further confirmed with a non-contrast CT scan which shows blood in the paramesencephalic subarachnoid cisterns (interpeduncular, crural, ambient, and quadrigeminal cisterns). SAH is most commonly due to the rupture of a saccular (berry) aneurysm.

Saccular aneurysms are arterial outpouchings generally found at branch points of large arteries in the anterior circulation, usually on or near the Circle of Willis. Rupture of saccular aneurysms leads to bleeding into the subarachnoid space. Risk factors for SAH include hypertension, smoking, autosomal dominant polycystic kidney disease (ADPKD), and Ehlers-Danlos syndrome type IV. Clinically, SAH presents with a sudden onset “thunderclap” headache and signs of meningeal irritation. Diagnosis can be secured with a non-contrast CT of the head, which will most often show extravasated blood in the basal cisterns. Treatment for unruptured saccular aneurysms includes endovascular coiling or microsurgical aneurysm clipping. Acute treatment for subarachnoid hemorrhage includes emergent neurosurgical clipping or coiling, blood pressure lowering, and nimodipine to prevent vasospasm.

Thompson et al. discuss the American Heart Association (AHA) and American Stroke Association recommendations for the management of patients with unruptured intracranial aneurysms. The authors note that endovascular coiling is associated with a reduction in procedural morbidity and mortality compared to surgical clipping, but that there is an overall higher risk of recurrent rupture. The authors recommend further study of coiling versus clipping with large-scale prospective trials that include aneurysm size and location as predictors of outcome.

Incorrect Answers:
Answer 1: Cerebral amyloid angiopathy (CAA) is the most common cause of lobar intraparenchymal hemorrhage. CAA usually occurs in older patients. Presentation is variable depending on the location of the hemorrhage. As the hemorrhage is intraparenchymal, blood would not be expected to layer in the basal cisterns.

Answer 2: Rupture of a Charcot-Bouchard aneurysm leads to intraparenchymal hemorrhages, most often in the basal ganglia. Charcot-Bouchard aneurysms are small outpouchings associated with chronic hypertension and are most often in the lenticulostriate vessels.

Answer 3: Rupture of a middle meningeal artery usually occurs in the setting of trauma and would lead to an epidural hematoma. In patients with expanding epidural hematomas, patients may initially be asymptomatic (lucid interval), followed by a rapid neurologic decline with loss of consciousness. On a non-contrast CT of the head, a lenticular hematoma that respects suture lines would be expected in patients with epidural hematomas.

Answer 5: Shearing injuries to the bridging veins may result from head trauma, especially in patients with cerebral atrophy (elderly, chronic alcohol users, and previous traumatic brain injury). This leads to a subdural hematoma, which can present with acute to subacute headache, confusion, seizures, and focal neurologic deficits. Subdural hematomas show a crescent-shaped hematoma that does not respect suture lines on non-contrast head CT.

Bullet Summary:
Subarachnoid hemorrhages present with sudden onset and severe headaches and most often result from rupture of a saccular aneurysm in the subarachnoid space.