What signs, symptoms and tests can rule in and rule out SAH and to what degree?
Title of Paper:
Spontaneous Subarachnoid Haemorrhage: A Systematic Review and Meta-Analysis Describing the Diagnostic Accuracy of History, Physical Exam, Imaging, and Lumbar Puncture with an Exploration of Test Thresholds.
Journal and Year:
Academic Emergency Medicine June 2016
Name of Contributor:
Systematic review and meta-analysis – 22 studies included
Summary of Results:
Authors analysed what symptoms and signs were highly indicative of SAH. They then looked at clinical decision rules and their ability to rule in and rule out the disease (SAH). They then looked at the sensitivity and specificities of 1. non-contrast CT (within 6 hours and after 6 hours) and LP for SAH.
Robust study with pooled data adds to strong evidence on what and what should not be done for SAH. Authors had good strategies to grade papers as “high risk for bias and low risk for bias”.
SRs and MAs have long been considered the gold standard evidence in EBM.
SRs and MAs have received a lot of bad press lately because they can also just pile up bad-evidence and make it look like good evidence by beefing numbers.
Clinical Bottom Line:
The evidence of benefit in LP post-6hr CT is in question, certainly in patients not at high risk. If a good, validated clinical decision rule were to be readily available, we could use this to facilitate shared decision making and avoid the risks of over testing.
Make sure you read the paper, particularly the likelihood ratios for parts of the history and examination, to help inform your gestalt.
Other FOAMed Resources: