Up to 17% of all strokes occur in patients originally admitted for another reason, according to a study published in the March 2015 Journal of Hospital Medicine. But common mimics like delirium and seizure can confound timely stroke diagnosis in the hospital.
“Studies suggest that at least half of stroke code activations in the hospital are mimics,” said Shyam Prabhakaran, MD, MS, professor of neurology and medical social sciences at Northwestern University Feinberg School of Medicine in Chicago.
To address this issue, his research group developed and validated the 2CAN score, a tool that uses risk factors to distinguish true strokes from mimics in the inpatient setting. The score was named after four elements that independently predict stroke: Clinical deficit (1 or 3 points, depending on severity), Cardiac procedure during hospitalization (1 point), Atrial fibrillation history (1 point), and New admission within 24 hours (1 point).
In a single-center study, the authors observed that a 2CAN score of 2 or greater had 92.2% sensitivity, 69.6% specificity, 62.2% positive predictive value, and 94.3% negative predictive value for identifying stroke, according to results published in the December 2018 Stroke. The score is the first tool targeted at helping non-neurologist clinicians diagnose acute stroke in the hospital, according to the paper.
Dr. Prabhakaran, senior author of the study, recently spoke with ACP Hospitalist about how the score was developed and how hospitalists can better discern stroke from its mimics.
Q: What led you to develop the 2CAN score?
A: There is currently a major gap in this area, as non-neurologists and neurologists struggle with distinguishing strokes from mimics, especially in the inpatient setting where many confounders, such as medications and acute medical illness, make it more difficult than in the emergency department.
Q: What are some common examples of medications or acute illnesses that can mimic a stroke?
A: Sedation and narcotics can result in altered mental status, which can sometimes be confused with aphasia from stroke or brain stem stroke in some instances. Likewise, in the elderly, an infection, such as in the urinary tract, can result in stroke-like deficits produced by encephalopathy.
Q: Which factors appear to be most important for distinguishing stroke from other conditions?
A: Those elements in the score turned out to be the most important factors, with clinical deficit akin to using the Cincinnati Prehospital Stroke Scale (scored in the field by paramedics). This scale identifies those with focal deficits involving the face, arm, or speech.
Q: Why is a tool like this useful for hospitalists in particular?
A: The idea was to try to create something that could be applied by non-neurologists. Internists, hospitalists, surgeons, physician assistants, and nurses could use a simple screen such as ours to activate appropriate consulting services and do it, hopefully, sooner. In the case of stroke, time is essential. But even for nonstroke, it may be appropriate to activate services to manage acute problems very quickly and allocate resources appropriately.
Q: What are the most important take-home messages from your study?
A: We think the score is mostly common sense. This [score] should be simple to use at the bedside. A clinical screen to assess for focal deficits, like those used by paramedics, is important. Atrial fibrillation and recent cardiac procedure are more likely to cause stroke. Recent admissions may be missed strokes in the emergency department (which occurs in about 10%) or, inversely, prolonged hospitalization is less likely to be associated with stroke since multiple medical issues predominate.
Q: Do you have any tips for how hospitalists can distinguish in-hospital stroke from its mimics?
A: I would encourage clinicians to assess for focal deficits (unilateral hemiparesis, facial droop) rather than diffuse deficits (confusion, generalized weakness), as the former are much more likely to be associated with stroke. In addition, considering the patient situation, [including] risk factors, recent procedures, and time from admission, may be helpful in raising the suspicion for stroke above other stroke mimics.
Q: Is this tool ready for clinical practice?
A: We are cautious about single-center studies and lack of external independent validation. A prospective validation study, especially with external sites, is necessary. We would encourage others to pilot it at their hospitals and monitor the results.