Matthew Maximillian Padrick, MD, BA

Dolmans LS, Lebedeva ER, Veluponnar D, van Dijk EJ, Nederkoorn PJ, Hoes AW, et al. Diagnostic Accuracy of the Explicit Diagnostic Criteria for Transient Ischemic Attack: A Validation Study. Stroke. 2019;50:2080–2085

The diagnosis of Transient Ischemic Attack (TIA) has remained one of the murkier diagnoses a physician can encounter, and yet it yields a disproportionately large impact on patient wellbeing. Diagnoses can be given haphazardly, say in a busy emergency department, for brief dizziness, confusion, tingling, or just not feeling quite right. I have seen a patient who was given the diagnosis after less than a minute of isolated whole body shivering. ED neurology consults are a luxury, not the rule, and “follow up with neuro” discharge action plans may never materialize.

With the growing acceptance and implementation of the POINT and CHANCE trials, these TIA diagnoses carry significant weight. Patients with no clear indication may suddenly find themselves on dual antiplatelet therapy, which is certainly not without risk. On the other end of the spectrum, missing the diagnosis significantly increases our patients’ risk of stroke within 6 months. There have been multiple scales created to help with risk stratification, and the quest for reliable biomarkers is well underway. 

The Markers in the Diagnosis of TIA (MIND TIA) trial was created in an attempt to find serum biomarkers to aid in diagnosis, and while no reliable biomarker has yet to emerge, the database has allowed Dolmans et al. to perform a retrospective validation study of a tool ideally used by general practitioners and emergency departments to help parse out TIA vs non-TIA. The modified Explicit Diagnostic Criteria for Transient Ischemic Attack (EDCT) is a five-point set of criteria that includes the following: 

  1. Sudden Onset of fully reversible neurological or retinal symptoms
  2. Duration <24 h
  3. At least 2 of the following:
    1. All symptoms are maximal in <1 min (no gradual spread)
    1. All symptoms occur simultaneously
    1. All symptoms are deficits (no irritative symptoms such as photopsias, pins, and needles)
    1. No headache accompanies or follows the neurological symptoms within 1 h
  4. None of the following isolated symptoms (can occur together with more typical symptoms): shaking spells, diplopia, dizziness, vertigo, syncope, decreased level of consciousness, confusion, hyperventilation associated paresthesia, unexplained falls, and amnesia
  5. No evidence of acute infarction in the relevant area on neuroimaging

The authors used data from patients suspected of TIA by a GP and referred to a TIA service in the region of Utrecht, the Netherlands, who participated in the MIND-TIA study. Patients provided clinical information with a standardized questionnaire 72 hours after onset, and a panel of 3 experienced neurologists ultimately determined the diagnosis based on all available diagnostic information, including a 6-month follow up. Two authors not on the expert panel scored the EDCT. Sensitivity, specificity, and predictive values were assessed using the panel diagnosis as reference.

206 patients were included in the study, of which 126 had TIA or minor stroke, and 80 had an alternative diagnosis. The modified EDCT was found to have a sensitivity of 98.4% (95% CI, 94.4-99.8), a specificity of 73.8% (62.7-83.0), negative predictive value of 96.7%, and positive predictive value of 85.5%.

The modified criteria listed above indicates a change in the language for the C group from “2 or more symptoms” to “all”, which increased specificity and positive predictive value while maintaining fantastic sensitivity and negative predictive value. 

There are limitations to the study, as the panel of experts only had the recorded history and questionnaire from which to come to a diagnosis. With TIA, however, the large majority of diagnoses will be based on history alone. Only two false negative TIA cases came as a result of employing the EDCT, and both were patients with diplopia, indicating this score is more reliable to diagnose anterior circulation TIA compared to posterior circulation. Barring these two cases, however, the EDCT is a wonderful tool in the primary care setting. Combining this score with other established risk stratification modalities such as the ABCD2 score should help funnel patients towards warranted consultations with a neurologist, and help avoid unnecessary testing and medications.