The recent description of sexual headaches1 prompts us to reemphasize symptomatic causes of this condition and the usefulness, or lack thereof, of spinal fluid xanthrochromia in the detection of subarachnoid hemorrhage (SAH). We report the history of a young woman with two sexual headaches who was initially believed to have a benign condition. Further investigation revealed two intracranial aneurysms, one of which had ruptured to produce SAH.

CASE REPORT

A thirty-three year old woman on an oral contraceptive presented with a severe headache following sexual intercourse. Three days prior to admission she had noted the onset of severe right parietal headache peaking one hour after sexual intercourse. An evaluation at another hospital revealed normal computed tomography (CT). There was partial relief of the headache with hydroxy-codone. She had persistent mild pain for the next three days with associated low back stiffness. Prior to presentation at our emergency room, she had acute onset of a severe right parietal headache during sexual intercourse at the time of orgasm. The headache was so severe that the patient held her head and then experienced a brief period of unresponsiveness with irregular breathing. Within ten minutes she had returned to her cognitive baseline without a change in headache intensity. General examination was remarkable only for marked nucal rigidity with Kernig=s and Brudzinski=s signs. Her neurologic examination was entirely normal. CT suggested possible small hemorrhage in the medullary cistern and was considered by most to be normal. Spinal fluid examination revealed 400,000 red blood cells in tube 1 with 311 white blood cells, and 280,000 red blood cells in tube 2. The fluid was spun down in the laboratory and no xanthochromia was reported, although upon later questioning, the spinal fluid, supernatant, was described as being straw colored. Complete blood count and a SMAC 16 were normal. Arteriography revealed an 8 mm anterior communicating artery aneurysm with evidence of hemorrhage as well as a smaller right middle cerebral bifurcation aneurysm. Surgical clipping of both aneurysms was successful.

DISCUSSION

We emphasize, first, that all patients with so-called benign coital headaches should be carefully evaluated for the possibility of a SAH from a ruptured aneurysm.1 Investigation must include lumbar puncture. As emphasized by Adams et. al.2 14.6% of subarachnoid hemorrhages have a negative CT scan. The finding of xanthochromia upon examination of the spun cerebrospinal fluid (CSF) has long been cited as indicated the presence of subarachnoid hemorrhage versus blood from a traumatic lumbar puncture. Xanthochromia usually appears within two to four hours of SAH, but may take as long as twelve hours. Rarely, however, xanthochromia may occur following a traumatic lumbar puncture if the cell count exceeds 100,000 to 200,000 cells/mm3. MacDonald and Mendelow3 noted that the presence or absence of xanthochromia was not dependent upon the time of the lumbar puncture in relation to cerebral hemorrhage. They noted that 20 patients had no blood visible on CT scan and that 7 of these 20 had blood in their CSF, but no xanthochromia. They concluded that it was bloodstained CSF that was important in the diagnosis of subarachnoid hemorrhage and not xanthochromia. Their major point was that a normal CT scan with absence of CSF xanthochromia does not rule out a ruptured intracranial aneurysm.
But how is xanthochromia determined? It is determined by visual inspection or spectrophotometry. We would emphasize that most neurologists are unaware of how it is determined in their own hospital. When xanthochromia is determined by a photometric method4 it is detected 100% of the time in true SAH. Xanthochromia is defined as extinctions exceeding 0.023 at wavelength 415nm and\or a peak in the absorption curve in the 450-460nm range.4 Visual inspection alone has a false-negative rate of 463 to 50%.5 Of note is the fact that none of the academic health centers in North Carolina employ photometric methods for the determination of xanthochromia.

In the case under discussion, the sudden onset of severe headache associated with sexual intercourse followed by nucal rigidity strongly suggested SAH. The concern, however, was whether the patient had had a Atraumatic tap.@ The initial attempt at lumbar puncture was performed by an intern in the emergency department and was unsuccessful. No fluid was obtained. The second attempt was performed by a third year emergency medicine house officer who went one interspace lower and immediately obtained bloody fluid without difficulty. The supernatant in both tubes 1 and 4 was observed to be straw colored. It was reported as showing no xanthochromia. Our laboratory does not perform a photometric analysis on CSF. Fortunately, because of the clinical presentation, the patient was taken to arteriography. The procedure showed both an anterior communicating artery aneurysm and a middle cerebral artery aneurysm which were treated successfully. We would emphasize that clinicians should not rely upon a laboratory determination of xanthochromia unless a spectrophotometric method is used.

References
1. Pascual J, Iglesias F, Oterino A, Vazquez-Barquero A, Berciano J. Cough, exertional, and sexual headaches: An analysis of 72 benign and symptomatic cases. Neurology 1996;46:1520-1524.
2. Adams HP, Kassell NF, Torner JC, Sahs AL. CT and clinical correlations in recent aneurysmal subarachnoid haemorrhage: A preliminary report of the Co-operative Aneurysm Study. Neurology 1983;33:981-988.
3. MacDonald A, Mendelow AD. Xanthochromia revisited: a re-evaluation of lumbar puncture and CT scanning in the diagnosis of subarachnoid haemorrhage. J Neurol Neurosurg Psychiatr 1988;51:342-344.
4. Vermeulen M, Hasan D, Blijenberg BG, Hijdra A, Van Gijn J. Xanthochromia after subarachnoid haemorrhage needs no revisitation. J Neurol Neurosurg Psychiatr 1989;52:826-828.
5. Soderstrom CE. Diagnostic significance of CSF spectrophotometry and computer tomography in cerebrovascular disease. A comparative study in 231 cases. Stroke 1977;5:606-612.