Abstract

Accurate identification of stroke patients is essential to ensure appropriate and timely treatment. Stroke mimics—patients initially suspected to have suffered a stroke who are subsequently diagnosed with a condition other than stroke—are estimated to account for 5–33% of suspected stroke patients conveyed by paramedics to a hospital stroke unit. The prevalence of stroke mimics in London has not been investigated although pan-London hospital data suggests that one quarter of all patients admitted to hyper-acute stroke units (HASUs) are stroke mimics.

Participants were recruited as part of a larger study investigating whether the use of the Recognition of Stroke in the Emergency Room (ROSIER) tool by ambulance crews improved pre-hospital stroke recognition. Only patients indicated by the ROSIER to have potentially suffered a stroke and conveyed to a participating HASU (n=256) were included.

A final diagnosis of stroke was received by 160 patients (“strokes”) while 96 patients received a final diagnosis of non-stroke (“mimics”), resulting in a stroke mimic rate of 38%. Mimics received a wide range of diagnoses, including seizure, syncope, brain tumour, non-organic stroke/symptoms, sepsis, somatisation, and migraine. Compared to strokes, mimics had a lower total ROSIER score, displayed fewer stroke-related symptoms, and presented with more symptoms not indicative of a stroke (e.g. loss of consciousness/syncope, seizure).

The stroke mimic rate is higher than reported by previous studies and pan-London hospital data. It is unlikely this higher rate is due to the use of the ROSIER since the specificity of the ROSIER is equal to the FAST in the pre-hospital setting (Fothergill et al, submitted). Stroke recognition in the pre-hospital setting needs to be improved in order to reduce the number of non-strokes falsely identified as stroke and to ensure these patients are taken to the appropriate facility for treatment.