A 56-year-old man presents to the emergency department after he develops a severe headache associated with photophobia, nausea, and vomiting. Noncontrast head computed tomography (CT) demonstrates subarachnoid blood within the basal cisterns and in the bilateral Sylvian fissures as well as early communicating hydrocephalus (Figure 24-1).
Noncontrast computed tomographic scan demonstrating subarachnoid hemorrhage (left) and early hydrocephalus (right).
What are the initial management considerations for this patient?
This patient’s clinical presentation suggests subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. He should be admitted to the neurological intensive care unit (NeuroICU). Two large bore IV lines as well as an arterial line for blood pressure management should be established. An initial systolic blood pressure goal of < 140 mm Hg should be instituted. Coagulopathy or platelet inhibition should be reversed if present. Intubation is reserved for patients who are unable to adequately protect their airway because of depressed mention. Ventricular drainage is also a consideration for patients with hydrocephalus who are unable to follow commands or present in poor neurological status.
What diagnostic studies are indicated for the investigation of SAH?
In the first 12 hours after the initial bleed, noncontrast head CT has a 98% to 100% sensitivity for the detection of SAH. This sensitivity decreases to 93% at 24 hours and to 57% to 85% after 6 days.1–7 If the initial head CT does not reveal SAH, a lumbar puncture with analysis of the cerebrospinal fluid (CSF) for xanthochromia should be performed.8
Imaging of the cerebral vasculature must be obtained to determine the source of the SAH. The gold standard for evaluation of cerebral vascular lesions remains catheter angiography. Less invasive modalities including magnetic resonance angiography (MRA) and CT angiography (CTA) may be initially utilized depending on availability and patient stability. Three-dimensional time-of-flight MRA has a sensitivity to detect cerebral aneurysms of between 55% and 93%.9–12 Dichotomizing by size, the sensitivity is 85% to 100% for aneurysms ≥ 5 mm but only 56% for those < 5 mm.11,13,14 CTA is more frequently utilized in the setting of SAH as it is faster and more readily available. In addition, it has an aneurysm detection sensitivity of between 77% and 100% and specificity between 79% and 100%.15–21
Catheter cerebral angiogram demonstrates posterior communicating artery aneurysm. Three hours later, the patient develops a third nerve palsy. How do you interpret this finding?
Newly diagnosed cranial nerve (CN) III palsy in the setting of a posterior communicating artery aneurysm suggests aneurysm instability and expansion (Figure 24-2). A noncontrast head CT should be immediately obtained to rule out rebleeding. Rebleeding is the major cause of death in patients who survive the initial hemorrhage but do not undergo surgical intervention. Early intervention is thus warranted in patients with aneurysmal SAH and especially in those demonstrating aneurysm instability.22–25
Internal carotid artery injection angiogram demonstrating a posterior communicating artery aneurysm.