Letters Subarachnoid haemorrhage

Cases may have been missed

BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c7406 (Published 30 December 2010) Cite this as: BMJ 2010;341:c7406
  1. Jonathan Lamb, doctor1
  1. 1East and North Hertfordshire NHS Trust, UK
  1. lambjn{at}googlemail.com

Perry and colleagues state that missing a subarachnoid haemorrhage in an otherwise alert patient could lead to catastrophic morbidity or death.1 However, in their study around 626 eligible patients did not receive either computed tomography or lumbar puncture to rule out subarachnoid haemorrhage. If the incidence of subarachnoid haemorrhage in these patients was only 3% (the incidence was 6.5% and 2.7% in the enrolled and missed patients respectively1), 19 cases would have been missed. Including these cases to create guidelines with 100% specificity might have led Perry and colleagues to different conclusions.

Patients were seen on average 8.8 hours after the beginning of the headache. If a potential diagnosis of subarachnoid haemorrhage had been missed in patients not investigated with either computed tomography or lumbar puncture the likelihood of rebleeding after discharge is quite low, given that 92% of rebleeding may occur in the first six hours after the initial haemorrhage.2 A patient with subarachnoid haemorrhage who was not fully investigated with computed tomography or lumbar puncture might not have rebled. The telephone follow-up used in the study may not have been sufficient to identify missed cases of subarachnoid haemorrhage.


Cite this as: BMJ 2010;341:c7406


  • Competing interests: None declared.


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