Ruptured intracranial aneurysms. A 56-year-old man is admitted to the neurologic intensive care unit (NICU, NeuroICU) after he develops a nonradiating frontal headache associated with photophobia, nausea, and one episode of nonbilious, nonbloody vomiting 30 minutes prior to his arrival at the emergency department. Noncontrast head computed tomography (CT) is consistent with acute subarachnoid hemorrhage—Blood is seen in the middle cerebral artery cisterns extending into the sylvian fissures bilaterally (Figure 21-1).
Noncontrast computed tomographic scan demonstrating subarachnoid hemorrhage.
What are your initial management considerations for this patient?
In order to make an appropriate treatment decision for this patient, etiology of the sub-arachnoid hemorrhage (SAH), whether aneurysmal or traumatic, must first be determined. Most frequently, intracranial aneurysms present to clinical attention with symptoms of major aneurysmal rupture and, therefore, constitute a distinct clinical entity in the setting of SAH. Although rupture nearly always results in SAH, it may also be accompanied by intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and, less often, subdural hemorrhage. This chapter discusses neurologic intensive care specific to surgical interventions for both ruptured and unruptured aneurysms. For NICU management of SAH and its related complications, see Chapter 1.
Symptoms that support a diagnosis of acute SAH due to aneurysmal rupture include:
Worst headache of life, often with vomiting.
Unilateral third cranial nerve palsy.
Sixth nerve palsy.
In the setting of concomitant ICH: hemiparesis, aphasia, amnesia, deterioration due to cerebral edema.
In many cases, patients may present with sudden severe headache, but without any focal neurologic symptoms.
What diagnostic studies should be performed before deciding on a definitive treatment strategy and what medications should he be started on in the meantime?
If an aneurysmal rupture is suspected, a noncontrast head CT scan must be performed immediately to assess for subarachnoid blood. In the first 12 hours after the initial bleed, noncontrast head CT has a 98% to 100% sensitivity for SAH, which decreases to 93% at 24 hours1-5 and to 57% to 85% after 6 days.6,7 If the head CT does not reveal SAH, a mass lesion, or hydrocephalus, a lumbar puncture with analysis of the cerebrospinal fluid for xanthochromia should be performed.8
The gold standard for evaluation of cerebral aneurysms remains digital subtraction angiography (DSA), which demonstrates the source of SAH in approximately 85% of patients. Two less invasive modalities are increasingly being used, magnetic resonance angiography (MRA) and CT angiography. Three-dimensional time-of-flight MRA has a sensitivity to detect cerebral aneurysms between 55% and 93%.9-12 Dichotomizing by size, the sensitivity is 85% to 100% for aneurysms 5 mm or greater, but only 56% for those less than 5 mm in size.11,13,14...