Ina Skagervik

Subarachnoid haemorrhage (SAH) has a high mortality and morbidity rate. Early SAH diagnosis allows the early treatment of a ruptured cerebral aneurysm, which improves the prognosis. Diagnostic cerebrospinal fluid (CSF) analyses may be performed after a negative computed tomography scan, but the precise analytical methods to be used have been debated. Here, we summarize the scientific evidence for different CSF methods for SAH diagnosis and describe their implementation in different countries. The principle literature search was conducted using PubMed and Scopus with the search items "cerebrospinal fluid", "subarachnoid haemorrhage", and "diagnosis". CSF analyses for SAH include visual examination, red blood cell counts, spectrophotometry for oxyhaemoglobin or bilirubin determination, CSF cytology, and ferritin measurement. The methods vary in availability and performance. There is a consensus that spectrophotometry has the highest diagnostic performance, but both oxyhaemoglobin and bilirubin determinations are susceptible to important confounding factors. Visual inspection of CSF for xanthochromia is still frequently used for diagnosis of SAH, but it is advised against because spectrophotometry has a superior diagnostic accuracy. A positive finding of CSF bilirubin is a strong indicator of an intracranial bleeding, whereas a positive finding of CSF oxyhaemoglobin may indicate an intracranial bleeding or a traumatic tap. Where spectrophotometry is not available, the combination of CSF cytology for erythrophages or siderophages and ferritin is a promising alternative.

acute CT brain scan revealed subtle hypodensity of the left MCA territory with narrowing of the proximal MCA on CT angiography ( fig. 1 a).Due to symptom regression during the next 30 min and the unknown time of symptom onset, aspirin was given but not thrombolysis.The next morning she had minimal dysphasia and central facial paresis only (NIHSS score 2).However, her symptoms were fluctuating and on day 3 she again progressed to global aphasia.Brain CT with angiography was unchanged ( fig. 1 a).Brain CTP was performed, consisting of a 50-second series using cinemode scanning and nonionic contrast medium, which is believed to have no brain damaging effects during acute stroke [9] .A significant decrease of relative cerebral blood flow (rCBF) to approximately 30 ml/100 g brain tissue/min in the left MCA territory was seen ( fig. 1 b).Conventional angiography with angioplasty of the occluded M1 segment was performed.Due to immediate normalization of the blood flow we renounced stenting.After the procedure our patient again exhibited minimal dysphasia only.Brain CTP 2 days and angiography 8 days later showed complete restoration of rCBF to approximately 70 ml/100 g/min ( fig. 2 a andb).Magnetic resonance imaging on day 5 revealed minor infarcts in the left insular lobe and internal capsule.Despite extensive cardiovascular workup an embolic source was not found.Having made