Testicular torsion is a urological emergency. It is a twisting of the testicle and the spermatic cord within the scrotum. As the blood vessels in the spermatic cord are blocked, the testicle lacks blood supply. If left untreated, the testicle will undergo ischemic necrosis and atrophy. The timing of treatment should be within 6 hours of the occurrence of torsion. In recent years, with the gradual improvement of the level of treatment, the understanding of this disease is also in progress. Testicular torsion occurs in adolescents, with the peak of the attack at the age of 14, and most cases are seen between the ages of 12 and 18. Most of the cases have no obvious cause before the onset of the disease, and the testicle can be twisted spontaneously. Some patients may have the testicle twisted during sleep or when they wake up after sleep, probably because the vagus nerve is excited during sleep and the contraction of the levator muscle increases with the erection of the penis. The typical symptoms of testicular torsion are sudden onset of pain and swelling on one side of the scrotum, which can start in the lower abdomen, inguinal region or thigh due to traction. The shortening of the torsional spermatic cord can cause elevation of the testicle, and the direction of torsion is mostly from lateral to midline torsion. However, in clinical practice, the onset of testicular torsion is often atypical, and because it overlaps with the peak age of onset of orchitis and epididymitis, it has often been misdiagnosed as orchitis or epididymitis and delayed in treatment. The main point of differentiation is that the latter has an older age of onset, more than 16 years old, and often has preexisting symptoms such as low-grade fever, urinary frequency, urinary urgency, and painful urination, while the testicles are in a normal position. A positive supination test is an effective test to diagnose testicular torsion, i.e. the patient’s pain is increased instead by supination of the affected testicle. Radionuclide scrotal scan or the use of Doppler ultrasound can show that the testicular blood supply is significantly reduced or even disappeared, which is an effective method for clear diagnosis. How to treat and prevent: 1. First of all, it is necessary to recognize this disease, because it often requires surgery once it is diagnosed, and the prognosis depends on the length of time from the onset to the surgery. According to statistics, if the testicle is operated within 6 hours of onset, the survival rate is 100%; if the testicle is operated within 6-12 hours, the survival rate is reduced to 70%; if the testicle is operated after 12 hours, the survival rate is reduced to 20%, which shows the importance of early diagnosis and treatment. 2, there is no effective prevention method, patients should go to the hospital immediately when symptoms appear. 3, primary care physicians, pediatricians and emergency physicians may not always be familiar with the disease and lack the necessary diagnostic equipment, it is advisable for children and patients to go directly to urology specialists to avoid delays and irreversible consequences. 4, suspected testicular torsion should be promptly surgically explored to reset the twisted testicle. If the blood supply to the testicle is poor after the reset and necrosis has occurred, it should be removed. Experienced urologists can perform manual repositioning for mild testicular torsion, but should closely observe the recovery of testicular blood supply. 5.Apply antibiotics to fight infection or prevent infection. Due to testicular torsion, the patient is in severe pain and resistance is reduced. Prophylactic antibiotics are necessary, and if the testicle is necrotic, antibiotics should be applied even more. Supportive therapy is also important to improve the body resistance. If one testicle is necrotic and has been surgically removed, close attention must be paid to the testicle on the healthy side, if there is discomfort, consult a doctor at any time. 7. Ultrasound can make a clear judgment on the blood flow of the testicle, which is of great value for the diagnosis of testicular torsion. Therefore, for sudden enlargement and pain of the testicle, scrotal ultrasound should be routinely performed to prevent leakage and misdiagnosis.