Clinical Vignette

A 66-year-old woman suddenly experienced a terrible temporal pain radiating into her forehead. The headache was so severe that she almost lost consciousness. She became nauseated, vomited, and felt disoriented. Her family called emergency medical services and had her brought to the emergency room. There, she was noted to be arousable but sleepy and confused. She had nuchal rigidity, photophobia, but no focal motor deficit. An unenhanced head computed tomography (CT) showed subarachnoid hemorrhage centered in the right sylvian fissure but no brain parenchymal abnormalities. Angiography demonstrated a ruptured middle cerebral artery aneurysm that was successfully clipped the next morning. The patient’s postoperative course was uneventful (Figs. 57-1 and 57-2).

Figure 57-1 Right Middle Cerebral Artery Aneurysm.

Figure 57-2 Middle Cerebral Artery Aneurysm Clipping.

Clinical Vignette

A 44-year-old postal worker presented with severe headache and nuchal rigidity to an emergency room. Unenhanced head CT revealed a subarachnoid hemorrhage centered in the basal cisterns, and further evaluation with catheter angiography revealed a large aneurysm arising from the basilar artery tip. After consultation between the neurosurgeon and the interventional neuroradiologist, the decision to perform endovascular coil embolization was made and the procedure was carried out successfully. The patient recovered fully after a 3-week hospital stay but required a second procedure after 6 months when follow-up angiography demonstrated a reexpansion of the neck of the aneurysm (Figs. 57-3 and 57-4).

Figure 57-3 Basilar Artery Tip Aneurysmal Bleed.

Figure 57-4 Basilar Artery Tip Aneurysm.

Clinical Presentation

The classic symptom of SAH is the “worst headache of one’s life.” Headaches associated with aneurysm rupture are frequently sudden in onset and often described as a severe thunderclap, excruciating and unbearable. The headache peaks rapidly and is frequently associated with pain extending across the head and toward the neck. The headache is usually global, with a constant viselike ache but occasionally throbbing. Unilateral aches or a retro-orbital stab-like pain, even fleetingly, raise the suspicion of a possible posterior communicating artery aneurysm.

Nausea and vomiting, neck pain, and altered consciousness are often associated with the headache. Approximately 30% of patients are found to be confused and lethargic after the ictus. During the moment of rupture, one fourth of patients become comatose and up to 40% have transient loss of consciousness.

Seizure-like activity may be observed. The incidence of true seizure activity in patients with SAH is estimated at 20%. Seizures in SAH are most commonly associated with middle cerebral artery (MCA) and anterior communicating artery (ACA) aneurysmal rupture causing intracerebral hematomas. Unfortunately, many patients recall having a sentinel hemorrhage or warning leak with a fleeting but severe headache within the 2–3 weeks before the major ictus. This headache is somewhat milder and usually not associated with meningismus; it is often ignored until the catastrophic return of a major rupture. When evaluating patients with SAH or sudden severe headache, special attention should be focused on the level of consciousness, focal neurologic signs such as hemiparesis or cranial nerve palsies, and signs of meningismus (Fig. 57-5). Meningismus frequently occurs, associated with nuchal rigidity. Brudzinski’s maneuver is an excellent means of evaluating meningismus; the examiner flexes the patient’s neck, precipitating hip flexion, knee flexion, and hamstring pain. Diplopia (due to abducens or oculomotor nerve palsies) and visual loss (chiasmal or optic nerve involvement) are caused by either cranial nerve compression from the aneurysmal dome or aneurysmal rupture and increased intracranial pressure (Fig. 57-6).

Figure 57-5 Clinical Manifestations of Cerebral Aneurysm Rupture.

Figure 57-6 Ophthalmologic Manifestations of Cerebral Aneurysms.

Examination of the optic fundi frequently discloses retinal or preretinal hemorrhage, subhyaloid hemorrhages, and occasional papilledema. Hemorrhage into the vitreous results in Terson syndrome, with scarring and epiretinal membrane formation (macular pucker) and eventually visual loss or distortion. Terson syndrome is a frequent cause of visual loss in SAH, which often goes unnoticed until the patient regains consciousness 1–2 weeks later. It is often related with more severe subarachnoid bleeds that cause loss of consciousness and papilledema. Its association with ACA aneurysms is less clear. The long-term prognosis for vision in this situation is fairly good; however, a vitrectomy is occasionally required.

When the aneurysm ruptures and dissects into adjacent brain tissue, various focal deficits may also be found on examination.

Differential Diagnosis

Patients presenting with a sudden apoplectic-type headache with associated meningismus or altered mental status must be considered to have an SAH until proven otherwise. However, SAH symptoms are sometimes confused with other disorders, including migraine headaches, hypertension, meningitis, cervical spine disorders, vertigo, and syncope. The various vascular headache syndromes remain the most common mimics.

Although migraines are often characterized by the patient as sudden, a careful history reveals that they typically have a gradual onset, with progression over minutes to hours, at times, to the degree of excruciating pain often with nausea and vomiting. Many are preceded by a classic visual aura of fortification spectra or scintillating lights gradually evolving then regressing over minutes before the headache occurs.

Cluster headache is another benign but severe headache syndrome with a well-defined clinical presentation. These headaches typically affect men, awakening them from sleep with a terrible unilateral periorbital and frontal pain. Cluster headaches are almost always associated with unilateral conjunctival injection, excessive lacrimation, and nasal stuffiness. They have a limited time course, usually lasting 45–60 minutes. They occur nightly in a temporal cluster for 6–8 weeks but may recur several times within a day. When this pattern is established, the diagnosis is secure. However, when the patient first experiences this headache in early midlife, a careful evaluation is indicated to exclude SAH. A therapeutic response to inhalation of 100% oxygen is diagnostic.

Paroxysmal hemicrania is a related disorder with an equal sexual distribution. Its response to indomethacin is a specific therapeutic diagnostic modality.

Orgasmic postcoital or exercise-induced headaches are another group of benign headaches that occur during sexual intercourse or with significant exercise. Those related to sexual activity generally occur precipitously at the peak of orgasm. These incapacitating severe headaches mimic the onset of an acute SAH and require the same full evaluation to exclude a ruptured aneurysm as other patients presenting with spontaneous sudden first-time severe headaches. Orgasmic, postcoital, or exercise-induced headaches are essentially diagnoses of exclusion.

Diagnostic Approach

The clinical diagnosis of SAH is best confirmed with brain CT (Fig. 57-7). Its sensitivity is highest in the first 24 hours after headache onset. A mild hemorrhage may wash away within 24 hours but approximately 50% of severe SAHs are still visible on CT 1 week after the ictus, and only one third are seen after 2 weeks. CT confirms the presence of SAH and frequently highlights associated issues such as hydrocephalus, intraparenchymal hematoma, intraventricular hemorrhage, or subdural hemorrhage.

Figure 57-7 Subarachnoid Hemorrhage.

Whenever the clinical suspicion of SAH exists but CT is negative, a lumbar puncture must be performed. A nontraumatic tap is crucial. When the presence of blood in the CSF does not clear between the first and fourth tubes, this is particularly suggestive of SAH (See Fig. 57-5). However, a more sensitive indicator is CSF xanthochromia, which represents lysis of erythrocytes with degradation of heme products into bilirubin within the CSF. This frequently renders the CSF a yellowish color within 1–3 hours after an SAH, and often persists for approximately 2–3 weeks.

When SAH is confirmed by CT or lumbar puncture, the cause of the hemorrhage is best evaluated with a four-vessel cerebral arteriogram. An aneurysmal source is found in 80–85% of arteriograms preformed for suspected SAH. If arteriography is negative after SAH, a repeat study should be performed approximately 10 days later. Although reliance on CT angiography rather than catheter angiography has been increasing, cerebral arteriography remains the accepted standard for evaluating patients with SAH.

To ensure proper communication, predict outcomes, and guide management, a clinical grade for each SAH is needed. Several grading scales are available; the most widely used is the Hunt–Hess scale—a five-tiered description of the patient’s state and an indicator of prognosis (Table 57-1).

Table 57-1 Hunt–Hess Grading Scale for Berry Aneurysms