Diagnostic Criteria for Transient Ischemic Attack (TIA)

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The diagnosis of transient ischemic attack (TIA) can be notoriously difficult, mainly because it is often solely based on history taking. Patients suspected of a TIA require an urgent assessment with timely start of antithrombotic therapy to reduce the risk of an early ischemic stroke.

Transient symptoms can be motor (in the frontal lobe or pyramidal tract), sensory (in the parietal area), or visual (monocular [transient monocular blindness] with retinal ischemia or binocular [e.g., hemianopia due to intracerebral visual tract or parietal, temporal, or occipital involvement]), or they can involve speech disturbance (aphasia or dysarthria). Other types of transient symptoms (e.g., vertigo, diplopia, dizziness, unsteady gait, or amnesia) can also occur with transient ischemic brain injury, although uncommonly, the occurrence of these symptoms or signs in isolation is explained by ischemia.

 

Original Explicit Diagnostic Criteria for TIA (EDCT) and the Modified Subcriteria (C1, C2, and C3)

A. Sudden onset of fully reversible neurological or retinal symptoms (typically hemiparesis, hemihypesthesia, aphasia, neglect, amaurosis fugax, hemianopsia, or hemiataxia)

B. Duration <24 h

C. At least 2 of the following:

  1. At least 1 symptom is maximal in <1 min (no gradual spread)
  2. 2 or more symptoms occur simultaneously
  3. Symptoms in the form of deficits (no irritative symptoms such as photopsias, pins, and needles, etc)
  4. No headache accompanies or follows the neurological symptoms within 1 h

C (Modified). At least 2 of the following:

  1. All symptoms are maximal in <1 min (no gradual spread)
  2. All symptoms occur simultaneously
  3. All symptoms are deficits (no irritative symptoms such as photopsias, pins, and needles, etc)
  4. No headache accompanies or follows the neurological symptoms within 1 h

D. 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

E. No evidence of acute infarction in the relevant area on neuroimaging

 

Common Symptoms Suggestive of TIA

Definite TIA

  • Focal cerebral or retinal symptoms lasting for seconds or minutes and typically lasting <1 hr
  • Motor weakness in two limbs or in one limb and the face
  • Sensory deficit in two limbs or in one limb and the face
  • Visual-field defect (homonymous hemianopia) or monocular blindness
  • Aphasia or dysarthria

Possible TIA: When combined, at least two of these symptoms suggest definite TIA; when isolated, they suggest possible TIA.

  • Unsteady gait
  • Diplopia
  • Vertigo, dizziness
  • Dysphagia

Usually not a TIA: “Bizarre spells” or isolated atypical symptoms are nonfocal or not clearly focal transient neurologic events for which the type of onset, topography, and course of symptoms do not fulfill the criteria for definite or possible TIA or another definite or possible neurologic syndrome (e.g., epilepsy or migraine).

  • Amnesia
  • Confusion
  • Incoordination of limbs
  • Partial sensory deficit (abnormal sensation or deficit in one limb or only in the face)
  • Unusual cortical visual symptoms (lone bilateral blindness and bilateral positive visual phenomena). Brief positive visual phenomena affecting one or both eyes or one hemifield are often described as flashes of light, stars, colored spots, or swirls of light. Transient positive visual phenomena involving both eyes include a variety of symptoms such as distortion, tilt of images, trails of images, and formed or unformed visual hallucinations.
  • Transient loss of consciousness
  • Headache
  • Phosphenes, photopsias, complex visual hallucinations, and palinopsia

 

References:

  1. Amarenco P. Transient Ischemic Attack. N Engl J Med. 2020;382(20):1933-1941. [Medline]
  2. Dolmans LS, Lebedeva ER, Veluponnar D, et al. Diagnostic Accuracy of the Explicit Diagnostic Criteria for Transient Ischemic Attack: A Validation Study. Stroke. 2019;50(8):2080-2085. [Medline]

 

Created Jul 6, 2020.