Playing by the Rules: Using Decision Rules Wisely Part 2, Nontraumatic Conditions
In part 2 of this 2-part review, the authors discuss validated clinical decision rules for nontraumatic conditions commonly encountered in the ED, and provide useful pearls and pitfalls pertaining to their use.
The greater the number of points, the higher the risk for imminent stroke, from low (0-3 points) to moderate (4-5 points) to high (6-7 points). The initial retrospective internal validation study found that the low, moderate, and high groups correlated to 7-day stroke risk of 1.2%, 5.9%, and 11.7%, respectively. Subsequently, the ABCD2 score was rapidly incorporated into institutional and national protocols for assessing risk for stroke and featured prominently in the 2009 American Heart Association guidelines on TIA, which recommend hospitalization for a score of 3 or greater.4,5
More recently, a multicenter prospective external validation study of more than 2000 TIA patients found that using the American Heart Association recommended cutoff of 3 or greater resulted in a sensitivity of 94.7% for detecting those patients who sustained a stroke within 7 days, but a specificity of only 12.5%.6 The investigators concluded that a specificity this low would require “almost all” of the TIA patients in their cohort (87.6%) to be admitted to the hospital—even though only 3.2% of their patients had a stroke within 90 days.6 Even when examined at other cutoff scores, the investigators found the ABCD2 score to have poor accuracy.6
Comment: Decreasing resource utilization is a laudable goal, but it does not appear that the ABCD2 score provides much guidance on which TIA patients can safely go home. Moreover, the increasing availability of advanced imaging and tele-neurology consultation in the ED have changed the landscape of TIA and stroke care. Many EPs have since argued that the ABCD2 score adds little to their evaluation.7
Abdomen
Alvarado Score
There are multiple clinical prediction rules for appendicitis. Among the most commonly utilized by EPs and surgical consultants are the Alvarado score and the Appendicitis Inflammatory Response Score. The Alvarado score was derived in 1986 based on a retrospective review of 305 abdominal pain patients of whom 227 (aged 4 to 80 years) had appendicitis.8 Factors were identified and weighted, which can be recalled through the mnemonic MANTRELS:
Migration of pain to the right lower quadrant: 1 point
Anorexia or acetone in urine: 1 point
Nausea or vomiting: 1 point
Tenderness in the right lower quadrant: 2 points
Rebound tenderness: 1 point
Elevation of the temperature > 37.3°C: 1 point
Leukocytosis >10K X 109/L: 2 points
Shift to the left of neutrophils (>75%): 1 point
The original article posited that a score of 5 or 6 was “compatible” with the diagnosis of acute appendicitis—necessitating further observation for possible appendicitis—and that higher scores indicated an increasing probability of disease.8 Of note, the rule has also been adapted for clinical settings where differentials are not easily obtainable with the left shift criterion removed; this is known as the modified Alvarado score and calculated out at a maximum of 9.9
