Thunderclap Headache With Normal CT and Lumbar Puncture

Stephen M. Davis MD, FRACP Geoffrey A. Donnan MD, FRACP Section Editors: Thunderclap headache (sudden and severe headache, maximum in intensity at onset) should raise concern for several life-threatening conditions, including subarachnoid hemorrhage (SAH). The traditional work-up for SAH is a noncontrast head CT followed by a lumbar puncture (LP) if the CT shows no apparent diagnosis. Patients with thunderclap headache and a normal examination, CT and cerebrospinal fluid analysis do not require angiography or other studies to exclude SAH.Several cases1–3 suggest otherwise and have reported patients with thunderclap headache and normal CT and LP results who are subsequently found to have aneurysms on digital subtraction angiography. These reports raise the point that some aneurysms cause headache by expansion, dissection or thrombosis and that angiography is important even after a negative standard work-up out of concern for incipient aneurysmal rupture.However, headache is a very common symptom and aneurysms detected on angiography do not necessarily imply that …