How Do I Perform a Lumbar Puncture and Analyze the Results to Diagnose Bacterial Meningitis?
Journal Club Summary
Landmark Article Series – UPDATE
Methodology Score: 2.5/5
Usefulness Score: 4/5
Straus SE, Thorpe KE, Holroyd-Leduc J.
JAMA. 2006 Oct 25;296(16):2012-22.
This overview article from the JAMA Rational Clinical Exam series showed a non-significant trend towards a decrease in post-LP headaches when using an atraumatic needle when performing the LP, replacing the stylet prior to removal of the LP needle, and early mobilization rather than bedrest after the procedure. They also reported guidelines for the interpretation of CSF results showing that a CSF-Blood Glucose ratio of <0.4, a CSF WBC count of >500, and a CSF lactate level of >3.5mmol/L all had very high likelihood ratios for bacterial meningitis. JC attendees expressed interest in the finding that the TOH biochemistry lab can perform CSF lactate levels upon request.
By: Dr. Sameer Vakani
(Presented October 2013)
Epi lesson: Fixed vs Random Effect Models
In meta-analysis, pooling of multiple study estimates often uses one of two statistical analysis techniques: a fixed effects or random effects model. A fixed effects model is used when you have low inter-study variability but high intra-study variability and studies with larger sample sizes have greater weight. A random effects model is preferred if you have high inter-study variability and high intra-study variability and in this case studies are more evenly weighted regardless of sample size.
By: Dr. Lisa Calder