A previously healthy 32-year-old man is brought to the ED “confused” and complaining of a severe headache for at least 12 hours despite over-the-counter pain medication. Because of his presentation, you suspect a subarachnoid hemorrhage, knowing that:
A plain CT scan will diagnose 97% of subarachnoid hemorrhages.
+If the patient has no papilledema, you can safely perform lumbar puncture prior to CT scanning.
+If the patient has a subarachnoid hemorrhage, the spinal fluid will be xanthochromic.
+MRI offers no significant advantage over CT scan in this setting.
+Blood pressure should be reduced if the diastolic pressure is greater than 100 mm Hg.
The most common site of a ruptured cerebral aneurysm is the anterior circle of Willis. A ruptured aneurysm causes an acute frontal headache that is aggravated by movement and recumbency. Intraparenchymal hemorrhage is frequently present. CT scan may be negative in up to 5% of cases of “fresh” subarachnoid hemorrhage; and, the percentage of false-negative studies is higher as the time from bleeding to CT scan increases. A lumbar puncture (LP) may be required to detect blood. Xanthochromia may develop within 4–6 hours. Papilledema may be a late (12–18 hours) finding and may not develop in some individuals. Other findings may include projectile vomiting, anisocoria, fluctuating mental status, hemiplegia, and diplopia. Acute treatment focuses on preserving cerebral perfusion. Blood pressure should not be acutely reduced unless diastolic pressures remain greater than 120 mm Hg. Vasodilator therapy (calcium channel blockers) has met with mixed success.