Stroke-Code Patients With Low NIHSS Score, No Acute Imaging Findings Often Misdiagnosed

older man laying in hospital bed with two nurses taking care of him
older man laying in hospital bed with two nurses taking care of him
The investigators observed a high rate of accurate diagnosis for acute cerebral ischemia, hemorrhagic stroke, and stroke mimics in the cohort.

In a study published in Neurology, researchers from Helsinki, Finland, found that patients with stroke admitted to the neurology department are typically diagnosed correctly, but misdiagnoses are common in patients with no acute findings on neuroimaging and patients with a National Institutes of Health Stroke Scale (NIHSS) score of 0 to 8. Misdiagnoses in these patients increase the length of emergency department stays and introduce unnecessary treatments, contributing to a substantial delay in receiving appropriate care.

A total of 1015 patients with stroke who were candidates for recanalization therapy were enrolled in the study. Patients were assessed using the NIH Stroke Scale (NIHSS), with scores of 0-8, 9-15, and >15, representing mild, moderate, and severe cases, respectively. In addition, medical record review, computed tomography (CT)-based neuroimaging, and blood sample analyses were performed. The primary end point was to determine the accuracy of diagnosis and consequences of misdiagnosis in patients with stroke eligible for recanalization in a neurology department with <20-minute door-to-thrombolysis times.

The investigators observed a high rate of accurate diagnosis of acute cerebral ischemia (91.1%), hemorrhagic stroke (99.2%), and stroke mimics (61.5%) in the cohort. A total of 150 patients (14.8%) were misdiagnosed at the admission evaluation; the vast majority (90.0%) demonstrated no acute imaging findings and 67.6% presented with a mild NIHSS score.

Significantly more patients with a misdiagnosis had no acute findings on initial imaging (20.6% vs 4.2%; P <.001) and were more likely to present with an NIHSS score of ≤8 vs 9-15 and >15 (19.4% vs 4.8% and 2.5%, respectively; P <.001).

In 70 patients, a misdiagnosis affected medical management. Specifically, misdiagnosis was associated with omission of thrombolysis, provision of unnecessary treatments, and a 56-hour median delay to administration of antiplatelet medication. In addition, misdiagnosis was associated with a significant increase in the number of days spent in the emergency department (median 6.6 [4.7–10.4] vs 5.8 [3.7–9.2] hours; P =.001).

The observational nature as well as the lack of a comparator group represent the study’s main limitations.

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Considering misdiagnoses are associated with an increase in resource wasting, the study’s investigators suggest that their “findings support increasing attention, research, and resourcing to further improve rapid admission diagnostics of acute neurologic patients.”


Pihlasviita S, Mattila OS, Ritvonen J, et al. Diagnosing cerebral ischemia with door-to-thrombolysis times below 20 minutes [published online July 11, 2018]. Neurology. doi:10.1212/WNL.0000000000005954