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Clinical Review

Subarachnoid haemorrhage

BMJ 2006; 333 doi: https://doi.org/10.1136/bmj.333.7561.235 (Published 27 July 2006) Cite this as: BMJ 2006;333:235

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Spectrophotometry should always be used to examine Cerebrospinal fluid in suspected subarachnoid haemorrhage

Dear Sir

We read with interest the review on subarachnoid haemorrhage by Al-
Shahi et al. and would like to comment on a couple of points in the
review.

Firstly we maintain that examination of the cerebrospinal fluid
should always be by spectrophotometry. Visually clear and colourless CSF
has, when analysed by spectrophotometry, shown significantly raised
bilirubin in patients who were subsequently diagnosed with ruptured
cerebral artery aneurysms (1,2). Visual inspection alone will miss some
subarachnoid haemorrhages. No clinical decision should therefore be made
on fluid examined only with the naked eye.

Secondly the authors state that if a computed tomogram and
cerebrospinal fluid are normal within two weeks of a sudden severe
headache, then subarachnoid haemorrhage is excluded. This statement should
be tempered with a note of caution. The evidence that bilirubin, detected
by spectrophotometry, is always present 2 weeks following a bleed is based
on evidence from patients with positive computed tomograms(3). In patients
with negative computed tomograms which may be negative because of late
presentation or small bleeds we cannot be certain that bilirubin will be
always be detected by spectrophotometry up to two weeks post event(4). If
there is a strong clinical history, but negative investigations, then a
clinical judgement to proceed to angiography should be made(5).

1. Cruickshank A, Beetham R, Holbrook I, Watson I, Wenham P, Keir G,
White P, Egner W. Spectrophotometry of cerebrospinal fluid in suspected
subarachnoid haemorrhage. BMJ 2005; 330: 138

2. Beetham R, et al. Visual inspection versus spectrophotometry in
detecting bilirubin in cerebrospinal fluid.
http://jnnp.bmjjournals.com/cgi/eletters/76/10/1452#722.

3. Vermeulen M, Hasan D, Blijenberg BG, Hijdra A, van Gijn J.
Xanthochromia after subarachnoid haemorrhage needs no revisitation. J
Neurol Neurosurg Psychiat 1989; 52: 826-8

4. A Working Group of UK NEQAS for Immunochemistry. National
Guidelines for analysis of cerebrospinal fluid for bilirubin in suspected
subarachnoid haemorrhage. Ann Clin Biochem 2003; 40: 481-8

5. O’Connell DM, Watson ID. Definitive angiographic detection of
subarachnoid haemorrhage compared with laboratory assessment of
intracranial bleed in CT-negative patients. Ann Clin Biochem 2003; 40: 269
-73

Competing interests:
None declared

Competing interests: No competing interests

12 September 2006
Ian B Holbrook
Consultant Clinical Biochemist
Peter Auld, Robert Beetham, Anne Cruickshank, Mike Fahie-Wilson, Geoff Keir, Dina Patel, Ian Watson, and Peter White
York Hospital YO31 8HE