Wednesday, March 6, 2013

Stroke or Stroke Mimic? Who Cares!

Suppose you're "lucky" enough to be taken to an experienced stroke center if you have stroke-like symptoms.  After all, they see strokes every day, are experts in the diagnosis of stroke, and have given thousands of patients thrombolytics.  However, how often might they be wrong, you ask?

Oh, they estimate about 1 in every 50.  But, truthfully, it's probably much worse.

This is a multi-center observational cohort that purports to identify the percentage of patients treated with tPA and subsequently diagnosed with stroke mimics.  Out of the 5518 patients in their cohort, 100 were identified as stroke mimics.  Two of the 100 had sICH by NINDS criteria, but none died.  Therefore, these authors confirm, tPA is safe even when they're wrong, and the collateral damage of racing to tPA is low.

Of course, their methodology for identifying a stroke mimic is hugely skewed towards maintaining the diagnosis of ischemic stroke.  Only patients in whom clinical details did not suggest a vascular etiology or a clear alternative diagnosis were labeled mimics.  Patients with nonspecific features, non-contradictory imaging, or lacking definite evidence favoring stroke mimic remained as diagnoses of acute stroke.

So, even at experienced stroke research institutions – 1 in 50 with the most generous of criteria.  What's the chance real-world performance approaches anything close to this level of diagnostic skill?

The authors, of course, declare multiple financial conflicts of interest with the manufacturer of tPA.

"Safety of Thrombolysis in Stroke Mimics : Results From a Multicenter Cohort Study"
www.ncbi.nlm.nih.gov/pubmed/23444310

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