Spectrophotometry of cerebrospinal fluid in suspected subarachnoid hae
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《英国医生杂志》
1 Department of Biochemistry, Southern General Hospital, Glasgow G51 4TF, 2 Frenchay Hospital, Bristol, 3 York Hospital, York, 4 Walton Centre for Neurology and Neurosurgery, Liverpool, 5 Victoria Hospital, Kirckaldy, 6 Department of Neuroimmunology, National Hospital for Neurology and Neurosurgery, London, 7 Department of Immunology, Northern General Hospital, Sheffield
Correspondence to: A Cruickshank anne.cruickshank@sgh.scot.nhs.uk
Introduction
Computerised tomography can miss some cases of subarachnoid haemorrhage. Diagnostic sensitivity has been reported to decrease from 92% on the day of the bleed to 58% on day five.1 Because of this, it has been recommended that where subarachnoid haemorrhage is suspected but computerised tomography is normal, lumbar puncture should be done to exclude the presence of haem pigments (bilirubin and oxyhaemoglobin) in cerebrospinal fluid.2 After subarachnoid haemorrhage, haemolysis of subarachnoid erythrocytes releases haemoglobin, which is converted to bilirubin. Bilirubin concentration reaches a maximum at about 48 hours and may last for two to four weeks after extensive bleeding.3
In the two cases described here, spectrophotometry found increased bilirubin in cerebrospinal fluid providing evidence that subarachnoid haemorrhage had occurred; in each case the appearance of cerebrospinal fluid was normal. Without spectrophotometry the diagnosis may have been missed. Recent published guidelines have emphasised the poor sensitivity of visual inspection of cerebrospinal fluid for xanthochromia (yellow or reddish discolouration), and the importance of spectrophotometry.4 Many laboratories, however, continue to report the absence of haem pigments based on visual inspection.5 Spectrophotometry should be used to confirm the absence of haem pigments in cerebrospinal fluid. After lumbar puncture, the least blood stained sample of cerebrospinal fluid should be protected from light and sent immediately to the laboratory for spectrophotometry.
Spectrophotometry should be used to confirm the absence of haem pigments in cerebrospinal fluid
Contributors: All authors had the idea. Details of each case were provided by RB. The paper was written by AC and RB. AC is guarantor.
Funding: None.
Competing interests: None declared.
Ethical approval: Not needed.
References
Kassell NF, Torner JC, Haley EC Jr, Jane JA, Adams HP, Kongable GL. The international cooperative study on the timing of aneurysm surgery. Part 1: overall management results. J Neurosurgery 1990;73: 18-36.
Wasserberg J, Barlow P. Lumbar puncture still has an important role in diagnosing subarachnoid haemorrhage. BMJ 1997;315: 1598-9.
Fishman RA. Cerebrospinal fluid in diseases of the nervous system. London: WB Saunders, 1980.
UK National External Quality Assessment Scheme for Immunochemistry Working Group. National guidelines for analysis of cerebrospinal fluid for bilirubin in suspected subarachnoid haemorrhage. Ann Clin Biochem 2003;40: 481-8.
Edlow JA, Bruner KS, Horowitz GL. Xanthochromia. Arch Pathol Lab Med 2002;126: 413-5.(Anne Cruickshank, consultant chemical pa)
Correspondence to: A Cruickshank anne.cruickshank@sgh.scot.nhs.uk
Introduction
Computerised tomography can miss some cases of subarachnoid haemorrhage. Diagnostic sensitivity has been reported to decrease from 92% on the day of the bleed to 58% on day five.1 Because of this, it has been recommended that where subarachnoid haemorrhage is suspected but computerised tomography is normal, lumbar puncture should be done to exclude the presence of haem pigments (bilirubin and oxyhaemoglobin) in cerebrospinal fluid.2 After subarachnoid haemorrhage, haemolysis of subarachnoid erythrocytes releases haemoglobin, which is converted to bilirubin. Bilirubin concentration reaches a maximum at about 48 hours and may last for two to four weeks after extensive bleeding.3
In the two cases described here, spectrophotometry found increased bilirubin in cerebrospinal fluid providing evidence that subarachnoid haemorrhage had occurred; in each case the appearance of cerebrospinal fluid was normal. Without spectrophotometry the diagnosis may have been missed. Recent published guidelines have emphasised the poor sensitivity of visual inspection of cerebrospinal fluid for xanthochromia (yellow or reddish discolouration), and the importance of spectrophotometry.4 Many laboratories, however, continue to report the absence of haem pigments based on visual inspection.5 Spectrophotometry should be used to confirm the absence of haem pigments in cerebrospinal fluid. After lumbar puncture, the least blood stained sample of cerebrospinal fluid should be protected from light and sent immediately to the laboratory for spectrophotometry.
Spectrophotometry should be used to confirm the absence of haem pigments in cerebrospinal fluid
Contributors: All authors had the idea. Details of each case were provided by RB. The paper was written by AC and RB. AC is guarantor.
Funding: None.
Competing interests: None declared.
Ethical approval: Not needed.
References
Kassell NF, Torner JC, Haley EC Jr, Jane JA, Adams HP, Kongable GL. The international cooperative study on the timing of aneurysm surgery. Part 1: overall management results. J Neurosurgery 1990;73: 18-36.
Wasserberg J, Barlow P. Lumbar puncture still has an important role in diagnosing subarachnoid haemorrhage. BMJ 1997;315: 1598-9.
Fishman RA. Cerebrospinal fluid in diseases of the nervous system. London: WB Saunders, 1980.
UK National External Quality Assessment Scheme for Immunochemistry Working Group. National guidelines for analysis of cerebrospinal fluid for bilirubin in suspected subarachnoid haemorrhage. Ann Clin Biochem 2003;40: 481-8.
Edlow JA, Bruner KS, Horowitz GL. Xanthochromia. Arch Pathol Lab Med 2002;126: 413-5.(Anne Cruickshank, consultant chemical pa)