Original Article: Point-of-Care Ultrasonography in Family Medicine [Editorials]
Issue Date: August 15, 2018
See additional reader comments at: https://www.aafp.org/afp/2018/0815/p200.html
To the Editor: The editorial by Drs. Bornemann and Barreto describes a broad range of possible uses of point-of-care ultrasonography (POCUS) in primary care. With appropriate training, there is a good evidence base for the use of POCUS in patients with possible skin abscess, suspected community-acquired pneumonia, and left ventricular dysfunction.
However, it is always important to remember the potential harms and unintended consequences of introducing a new diagnostic or screening test. For example, the authors include the use of POCUS to identify thyroid lesions, a practice that is likely to do far more harm than good. In countries where physicians routinely scan the thyroid using POCUS, there is an epidemic of overdiagnosis: detection of small lesions of undetermined significance that are too often treated as cancer, resulting in considerable morbidity.1 For example, widespread use of POCUS in South Korea led to a more than 10-fold increase in the incidence of thyroid cancer, with no effect on mortality.1 POCUS should be used only by clinicians with adequate training, and in clinical scenarios in which there is solid evidence that its use improves patient outcomes.
Editor's Note: Dr. Ebell is Deputy Editor for Evidence-Based Medicine for AFP. He was formerly a member of the U.S. Preventive Services Task Force and currently serves as editor-in-chief of Essential Evidence Plus, a primary care medical reference.
In Reply: Dr. Ebell brings up an excellent point, with which I agree wholeheartedly. Although the physiologic risk of ultrasound waves on human tissue is very low, there are significant risks relating to the potential for overdiagnosis of pathology that would have otherwise remained subclinical. As smaller, less expensive “pocket” ultrasound machines are becoming increasingly available, the risk of increasing rates of overdiagnosis must be taken into consideration.
POCUS should be used only when the best available evidence suggests that the benefits will outweigh the risks. In the example that Dr. Ebell used, individuals were screened for thyroid cancer with ultrasonography leading to overdiagnosis and overtreatment. The key point here is that these individuals were asymptomatic. The evidence is strong that asymptomatic individuals should not be screened for thyroid cancer because the harms clearly outweigh the benefits.1
However, POCUS still has the potential to be beneficial in the evaluation of thyroid nodules that are already clinically evident. In individuals who have a palpable thyroid nodule or a nodule that was found incidentally on imaging, ultrasonography can stratify the risk of malignancy and determine the need for evaluation via fine-needle aspiration.2 Furthermore, if a nodule is found to be high risk, ultrasound guidance can improve the effectiveness of fine-needle aspiration over palpation-based techniques.3