Sudden intense headache commonly develops in subarachnoid hemorrhage. Subarachnoid hemorrhage can be easily diagnosed using head computed tomography (CT) or head magnetic resonance imaging (MRI). We treated two patients with subarachnoid hemorrhage who could not be diagnosed on the basis of imaging findings. We diagnosed them with subarachnoid hemorrhage after performing lumbar puncture. Here, we report the case findings.Case 1: An 82-year-old manHe developed sudden intense headache while going to eat at home. Head CT did not reveal a clear subarachnoid hemorrhage. The iso-intensity mass was seen in basal cistern by head MRI. However, head magnetic resonance angiography (MRA) revealed an aneurysm in the anterior communicating artery. Cerebrospinal fluid extracted after lumbar puncture was clear. We considered the patient to have an unruptured cerebral aneurysm.Case 2: A 38-year-old womanShe developed sudden intense headache and vomited twice while relaxing at home. The iso-intensity mass was seen in basal cistern by head MRI. However, head MRA revealed an aneurysm in the right internal posterior communication artery. Cerebrospinal fluid extracted after lumbar puncture had a light red color. We considered the patient to have subarachnoid hemorrhage due to a ruptured cerebral aneurysm, and performed emergency clipping and craniotomy.Consideration and conclusionWe think that performing an imaging examination in all patients with headache is unnecessary. We performed an imaging examination only when we suspected subarachnoid hemorrhage after analyzing a patient’s medical history. If subarachnoid hemorrhage is suspected in a case with no abnormal imaging findings, lumbar puncture should be considered.
