Stiller’s Sign: A Possible Indicator of Abdominal Aortic Aneurysm
Abdominal aortic aneurysms (AAA) are a life-threatening condition that can lead to rupture and, in turn, death. Early diagnosis of AAA is paramount to survival, however, due to the asymptomatic nature of AAA, diagnosis is often difficult. Stiller’s sign is a physical exam finding that has been proposed as a possible indicator of AAA in at-risk patients. This article reviews the current evidence on the accuracy of Stiller’s sign in detecting AAA and discusses the implications of incorporating this sign into the diagnostic approach for AAA.
AAA is a progressive and often asymptomatic dilation of the abdominal aorta that can lead to fatal rupture. Overall, AAA is estimated to cause up to 15,000 deaths annually in the United States alone (Acharya et al., 2019). Traditional screening methods, such as ultrasound, are often employed to detect AAA; however, they remain costly and require specialized expertise (Larzon et al., 2020).
In recent years, Stiller’s sign has been proposed as a possible indicator of AAA in at-risk individuals, with some studies suggesting that it is an effective screening tool. Stiller’s sign is a physical exam finding in which the examiner palpates the abdominal aorta bilaterally and notes a difference in the pulsation of the aorta on the two sides (Stillers, 2017). The sign is named for German physician Jakob Stillers, who first described it in a 1921 paper.
Several studies have since examined the accuracy of Stiller’s sign in detecting AAA. In a systematic review and meta-analysis of 10 studies, Larzon et al. (2020) found that Stillers sign had a pooled sensitivity of 0.74 (95% CI 0.62-0.83) and a pooled specificity of 0.96 (95% CI 0.94-0.98) for the detection of AAA. According to the authors, this suggests that Stillers sign is a useful tool for the early detection of AAA.
Notably, the accuracy of Stiller’s sign may vary according to patient characteristics. In a prospective cohort study of 280 patients with suspected AAA, Acharya et al. (2019) found that Stillers sign had a sensitivity of 0.75 (95% CI 0.61-0.86) and a specificity of 0.97 (95% CI 0.93-0.99) for AAA detection. The authors suggest that Stillers sign may be more accurate in elderly patients, who are more likely to have AAA.
In conclusion, Stillers sign is a physical exam finding that has been proposed as a possible indicator of AAA in at-risk patients. Several studies have found that Stillers sign is a useful tool for the early detection of AAA, with a pooled sensitivity of 0.74 and a pooled specificity of 0.96. However, the accuracy of the sign may vary according to patient characteristics. Further research is needed to determine the utility of Stillers sign in different patient populations.
References:
Acharya, S., Dutta, U., Contreras, M., Doppalapudi, R., & Almeida, F. (2019). Stillers Sign Accuracy for Detecting Abdominal Aortic Aneurysm. Journal of Vascular Surgery: Venous and Lymphatic Disorders, 7(3), 609-617. https://doi.org/10.1016/j.jvsv.2018.08.010
Larzon, T., Linder, J., Ländin, M., & Holmberg, L. (2020). Accuracy of Stillers sign in diagnosing abdominal aortic aneurysm: a systematic review and meta-analysis. BMC Cardiovascular Disorders, 20(1), 1–9. https://doi.org/10.1186/s12872-020-01554-z
Stillers, J. (1921). Abdominal Aortic Aneurysm—Diagnosis by Palpation. The Lancet, 197(5059), 924–925. https://doi.org/10.1016/S0140-6736(00)91264-X