SYMPTOMS
■ Characterized by sudden onsetof severe headache
■ May be preceded by activities that increase ICP (intercourse, cough-
ing, weight lifting)
■ N/ V (in majority)
■ Other possible symptoms include seizures, neck stiffness, preceding less
severe headache (“sentinel bleed”).EXAM
■ Depends on degree of hemorrhage and inflammatory response
■ Fifty percent have a completely normal examination.
■ Hunt and Hess classification:
■ Grades I and IIhave good prognosis: Headache with nuchal rigidity
+/– 3rd or 6th cranial nerve palsy; normal mental status.
■ Grade III are at risk for rapid deterioration (50% survival): Drowsiness,
confusion, +/– mild focal deficit.
■ Grades IV, V have poor prognosis: Stupor, hemiparesis, deep coma,
decerebrate posturing.DIAGNOSIS
■ Head CT without contrast (see Figure 15.4)
■ Symptoms <24 hours = sensitivity > 90%.
■ Symptoms for 1 week = sensitivity < 50%.
■ LP if CT negative; positive CSF findings for SAH:
■ Grossly bloody
■ Persistently bloody
■ Xanthochromia (via spectrophotometry, NOT naked eye) ≥12 hours after
onset of headache = gold standard.NEUROLOGY
Polycystic kidney disease and
headache? Think SAH!FIGURE 15.4. Noncontrast head CT demonstrating acute subarachnoid blood.(Reproduced, with permission, from Stone CK, Humphries, RL. Current Emergency Diagnosis
and Treatment, 5th ed. New York: McGraw-Hill, 2004:372.)