Testicular torsion is a medical emergency that occurs when the testicle twists on its spermatic cord, cutting off the blood supply to the testicle, which can lead to ischemia. The principal symptom is rapid onset of testicular pain. The most common underlying cause in adolescents and neonates is a congenital malformation known as a "bell-clapper deformity" wherein the testis is inadequately affixed to the scrotum allowing it to move freely on its axis and susceptible to induced twisting of the cord and its vessels. Testicular malignancy is the most common cause in adults.
Symptoms include sudden onset of severe pain in one testicle, often accompanied by swelling and tenderness, there may also be nausea and vomiting, abdominal pain, and a high-riding testicle. Diagnosis is clinical, with a scrotal ultrasound for confirmation. Treatment may require emergency detorsion, which can be done manually, or surgically if the former is not possible