Testicular torsion and ectopic pregnancy present similarly to appendicitis, and both have serious morbidity if not quickly diagnosed.

The differential diagnosis for a child with abdominal pain is extensive. It includes problems from organs within the abdomen as well as from organs outside of the abdomen. Both testicular torsion and ectopic pregnancy can present with abdominal pain that mimicks appendicitis, and both can lead to significant morbidity if not quickly diagnosed. As a result, it is important to always perform a complete physical examination, including examining the genitals, when a child presents with abdominal pain.

Testicular torsion requires prompt diagnosis and intervention if the testicle is to be saved. Spermatogenesis may be lost within 4 to 6 hours of absent blood flow. It is the most common cause of testicular pain in boys older than 12 years, and is uncommon in boys younger than 10 years. Testicular torsion occurs in a testis that is inadequately fixated in the scrotum because of a redundant tunica vaginalis. This anatomical abnormality is called the bell-clapper deformity and is often bilateral. Testicular torsion usually presents with testicular pain and swelling, although in some cases may present with abdominal pain. The pain usually begins abruptly and without precipitating event. Occasionally there is a report of genital trauma prior to the onset of pain. The pain may be accompanied by nausea and vomiting. Physical examination will reveal swelling and erythema of the scrotal sac. The testis will be in a horizontal rather than vertical position and the cremasteric reflex will almost always be absent. Torsion of an undescended testis will present as abdominal pain; examination of the genitals will reveal an empty scrotal sac.

Suspicion of testicular torsion should lead to prompt intervention. In equivocal cases, a Doppler ultrasound may be useful and may reveal decreased blood flow to the affected testis. A ^99mTc-pertechnetate testicular flow scan is a good alternative to Doppler ultrasound. False-negative studies can occur; therefore, highly suspicious cases should be treated immediately without
waiting for radiologic imaging. When diagnosis occurs within 6 hours of the onset of torsion, as many as 90% of testes can be saved through either manual or surgical detorsion. Survival of the gonad depends on the amount of time elapsed since the onset of torsion, and on the degree of torsion. If the degree of torsion is >360 degrees, the testis may still be viable after 24 to 48 hours. Manual detorsion may be successful in approximately 25% of cases. Attempts at manual detorsion should not delay surgical consultation. Surgical intervention is indicated for failed manual detorsion, for removal of a nonviable testis, or as a first-line intervention for detorsion. Following detorsion, bilateral orchiopexy is necessary to prevent future episodes of torsion.