ABCD² Score for TIA Risk Stratification
The ABCD² score is a clinical tool used to stratify short-term stroke risk in a patient who has had a transient ischemic attack (TIA). It combines five weighted factors — Age, Blood pressure, Clinical features, Duration of symptoms, and Diabetes — hence the mnemonic A-B-C-D-D (ABCD²). Each factor contributes points, and higher totals identify patients at greater risk who warrant more urgent evaluation and secondary prevention.
A — Age
Age ≥60 years contributes 1 point. Older age is an independent contributor to post-TIA stroke risk, reflecting the greater burden of cerebrovascular disease in this population.
B — Blood Pressure
A blood pressure ≥140/90 mmHg at presentation adds 1 point. Elevated blood pressure is a key modifiable vascular risk factor, and its presence at the time of the event flags a higher-risk patient.
C — Clinical Features
This is one of the two highest-weighted factors. Unilateral weakness scores 2 points — the maximum for this category. Speech impairment without weakness scores 1 point. The distinction matters: focal motor weakness carries more weight than an isolated speech disturbance.
D — Duration
Symptom duration is the second heavily weighted factor. Symptoms lasting ≥60 minutes score 2 points, while symptoms lasting 10–59 minutes score 1 point. Longer-lasting deficits indicate higher risk.
D — Diabetes
A history of diabetes adds 1 point. As with hypertension, diabetes is a major vascular risk factor contributing to the likelihood of subsequent stroke after a TIA.
High-yield
- ABCD² = Age, Blood pressure, Clinical features, Duration, Diabetes.
- Clinical features and Duration are the only categories that can score 2 points each; the others score 1 point.
- Unilateral weakness (2 points) outweighs speech impairment without weakness (1 point).
- Duration ≥60 min = 2 points; 10–59 min = 1 point.
- Age ≥60, BP ≥140/90, and Diabetes each contribute 1 point.
- The score is applied after a TIA to estimate short-term stroke risk and guide urgency of workup and prevention.
Pitfalls
- Confusing the point values: unilateral weakness is worth 2 points, not 1, while speech impairment without weakness is worth 1.
- Forgetting that duration is graded — ≥60 min earns 2 points but 10–59 min earns only 1.
- Assuming every factor scores equally; only clinical features and duration reach 2 points.
- Using the wrong blood pressure threshold — the cutoff is ≥140/90 mmHg.
- Overlooking that speech impairment scores only when it occurs WITHOUT weakness; weakness itself is scored under the higher unilateral-weakness criterion.
Clinical pearls
- Think 'ABCD²' — the squared reminds you there are two D's: Duration and Diabetes.
- The two time-and-motor factors (Clinical features, Duration) drive the score most because they can each add 2 points.
- A TIA is a warning sign: the ABCD² score turns that warning into a triage decision.
Frequently asked
What do the letters in ABCD² stand for?
Age, Blood pressure, Clinical features, Duration, and Diabetes — with the squared indicating the two D's (Duration and Diabetes).
Which factors can earn 2 points?
Only Clinical features (unilateral weakness = 2) and Duration (≥60 minutes = 2). All other factors contribute a maximum of 1 point.
How is the clinical features category scored?
Unilateral weakness scores 2 points, whereas speech impairment without weakness scores 1 point.
How does symptom duration affect the score?
Symptoms lasting ≥60 minutes add 2 points, and symptoms lasting 10–59 minutes add 1 point.
What blood pressure threshold earns a point?
A blood pressure of ≥140/90 mmHg adds 1 point.
At what age does the patient receive a point?
Age ≥60 years contributes 1 point.
Does diabetes contribute to the score?
Yes — a history of diabetes adds 1 point.
Turn this into reasoning you can use on exam day — practice ABCD² Score for TIA Risk Stratification on branching cases where your decisions shape the patient.