...but they almost all do well! Only 5.1% of patients without stroke who receive TPA end up with intracerebral hemorrhage - so it's OK that we give TPA to a ton of patients without a confirmed diagnosis of stroke, right?
This is a retrospective Finnish registry study of 1,104 consecutive TPA patients enrolled in a prospective cohort. Of these, 119 had basilar artery occlusion, which is angiographically proven prior to treatment, and are excluded from their analysis, and a couple others were excluded for other reasons. This left 985 patients who were initially diagnosed with ischemic stroke, and, eventually, 14 of those patients were diagnosed as a stroke mimic such as migrane, epilepsy, or a demyelinating disorder. The authors then go on to say that stroke mimics such as these accounted for a mere 1.4% of all TPA patients, and none of them had ICH.
But, this isn't exactly a true reading of their data. The authors also state that 275 of their patients had "neuroimaging negative ischemic stroke", which is to say, their follow-up MRI detected no sign of infarct. Now, there is a false-negative rate on DWI MRI for stroke, but it's in the range of 5% for acute infarcts, and generally involves small lacunar, small cortical, and some posterior circulation strokes. Not only that, it's reasonable to suggest that around 40% of TIAs actually have DWI or FLAIR sequence abnormalities as well.
So, some of their "neuroimaging negative ischemic stroke" group probably does have ischemic stroke with false negative MRI - but not 30% of the study population. And, some of their neuroimaging positive group is likely false positive from TIA as well. These numbers for stroke mimics are also far below other reported case series, which have estimated 10-30% incidence, depending on whether TIAs are included.
I absolutely cannot fathom this line of reasoning and distortion Neurology is developing in justify recklessly pushing TPA onto a larger population.
"Stroke Mimics and Intravenous Thrombolysis"