A 10-year-old boy presents with acute scrotal pain, nausea, and a negative urine dipstick. What is the most likely diagnosis?

In a 10-year-old boy who presents with acute scrotal pain, nausea, and a negative urine dipstick, testicular torsion is the most likely diagnosis. Testicular torsion occurs when the spermatic cord becomes twisted, cutting off the blood supply to the testis. This condition is characterized by sudden onset of severe scrotal pain, which can also be accompanied by other systemic symptoms like nausea.

The absence of findings on a urine dipstick suggests that there is minimal or no infection or inflammatory process in the urinary system, which is consistent with testicular torsion, as it usually does not involve the urinary tract.

Acute orchitis and epididymitis typically present with urinary symptoms or a positive urine dipstick due to infection, which makes them less likely in this scenario. Severe Salmonella infection may cause various gastrointestinal symptoms but is not typically associated with acute scrotal pain. Thus, the clinical presentation aligns best with testicular torsion, necessitating prompt evaluation and surgical intervention to prevent testicular necrosis.