Xanthochromia

Abstract: Recently it was contended that it is bloodstained cerebrospinal fluid (CSF) that is important in the diagnosis of subarachnoid haemorrhage (SAH) and not xanthochromia, and also that a normal CT scan and the absence of xanthochromia in the CSF do not exclude a ruptured intracranial aneurysm. The CSF findings were therefore reviewed of 111 patients with a proven SAH. All patients had xanthochromia of the CSF. Lumbar punctures were performed between 12 hours and one week after the ictus. Xanthochromia was still present in all (41) patients after 1 week, in all (32) patients after 2 weeks, in 20 of 22 patients after three weeks and in 10 of 14 patients after four weeks. In six years we identified only 12 patients with sudden headache, normal CT, bloodstained CSF, and no xanthochromia. Angiography was carried out in three and was negative. All 12 patients survived without disability and were not re-admitted with a SAH (mean follow up 4 years). It is concluded that it is still xanthochromia that is important in the diagnosis of SAH and not bloodstained CSF. Furthermore a normal CT scan and the absence of xanthochromia do exclude a ruptured aneurysm, provided xanthochromia is investigated by spectrophotometry and lumbar puncture is carried out between 12 hours and 2 weeks after the ictus.

Abstract: Objective To identify high risk clinical characteristics for subarachnoid haemorrhage in neurologically intact patients with headache. Design Multicentre prospective cohort study over five years. Setting Six university affiliated tertiary care teaching hospitals in Canada. Data collected from November 2000 until November 2005. Participants Neurologically intact adults with a non-traumatic headache peaking within an hour. Main outcome measures Subarachnoid haemorrhage, as defined by any of subarachnoid haemorrhage on computed tomography of the head, xanthochromia in the cerebrospinal fluid, or red blood cells in the final sample of cerebrospinal fluid with positive results on angiography. Physicians completed data collection forms before investigations. Results In the 1999 patients enrolled there were 130 cases of subarachnoid haemorrhage. Mean (range) age was 43.4 (16-93), 1207 (60.4%) were women, and 1546 (78.5%) reported that it was the worst headache of their life. Thirteen of the variables collected on history and three on examination were reliable and associated with subarachnoid haemorrhage. We used recursive partitioning with different combinations of these variables to create three clinical decisions rules. All had 100% (95% confidence interval 97.1% to 100.0%) sensitivity with specificities from 28.4% to 38.8%. Use of any one of these rules would have lowered rates of investigation (computed tomography, lumbar puncture, or both) from the current 82.9% to between 63.7% and 73.5%. Conclusion Clinical characteristics can be predictive for subarachnoid haemorrhage. Practical and sensitive clinical decision rules can be used in patients with a headache peaking within an hour. Further study of these proposed decision rules, including prospective validation, could allow clinicians to be more selective and accurate when investigating patients with headache.

Abstract: It is crucially important to detect subarachnoid haemorrhage (SAH) in all patients in whom it has occurred to select patients for angiography and preventative surgery. A computerized tomography (CT) scan is positive in up to 98% of patients with SAH presenting within 12 h, but is positive in only 50% of those presenting within one week. Cerebrospinal fluid (CSF) bilirubin spectrophotometry can be used to determine the need for angiography in those few CT-negative patients in whom clinical suspicion of SAH remains high; it may remain positive up to two weeks after the event. A lumbar puncture (LP) should only be performed >12 h after the onset of presenting symptoms. Whenever possible collect sequential specimens. Always ensure that the least blood-stained CSF sample taken (usually the last) is sent for bilirubin analysis. Protect the CSF from light and avoid vacuum tube transport systems, if possible. Always use spectrophotometry in preference to visual inspection. All CSF specimens are precious and should always be analysed unless insufficient sample is received. Centrifuge the specimen at >2000 rpm for 5 min as soon as possible after receipt in the laboratory. Store the supernatant at 4 degrees C in the dark until analysis. An increase in CSF bilirubin is the key finding, which supports the occurrence of SAH but is not specific for this. In most positive cases, bilirubin will occur with oxyhaemoglobin.