Eliciting renal tenderness by sonopalpation in diagnosing acute pyelonephritis

Diagnosing acute pyelonephritis relies on the combination of historical, physical, and laboratory findings. Costovertebral angle tenderness is important, although its accuracy is unknown. Point-of-care ultrasound-guided palpation (sonopalpation) may aid clinicians in localizing pain to discrete anatomic structures in cases of suspected acute pyelonephritis lacking classic features. We describe three low-to-moderate pre-test probability cases wherein maximal tenderness was elicited by renal sonopalpation, aiding in the diagnosis of acute pyelonephritis. In a fourth case, absence of renal tenderness to sonopalpation in a patient exhibiting typical acute pyelonephritis features led to an alternate diagnosis. Therefore, renal sonopalpation may be useful in confirming or refuting suspected cases.