Scrotal complaints are relatively common in the emergency department, comprising at least 0.5% of all emergency department visits. Testicular torsion is a time-dependent diagnosis, a true urologic emergency, and early evaluation can assist in urologic intervention to prevent testicular loss. Ultrasound is the ideal imaging modality to evaluate the scrotal contents. 
The majority of cases occur in younger patients (< 25 years old) and are usually due to a congenital abnormality of the processus vaginalis. The history of onset may be spontaneous, exertional, or, in fewer instances, associated with trauma. Testicular torsion accounts for roughly one-quarter of scrotal complaints that present to the emergency department. 
The majority of cases occur in the adolescent age range (during periods of growth) but can occur at any age as well as pre- or perinatal. Testicular torsion is the most significant cause of testicular loss.
As the testicle twists around the spermatic cord, venous blood flow is cut off, leading to venous congestion and ischemia of the testicle. The testicle will become tender, swollen, and possibly erythematous. As the testicle further twists, arterial blood supply is cut off which leads to further testicular ischemia and eventually necrosis. 
Testicular torsion often presents as abrupt onset of unilateral scrotal pain. The pain may be constant or intermittent, but not positional. The patient may have associated symptoms of nausea or vomiting. There may be associated lower abdominal and inguinal pain, or alternatively, these may be the presenting complaint rather than scrotal pain.
The testicle may be in an abnormal or transverse lie and may be in the high position. The testicle may be swollen, erythematous, and have an absence of the normal cremasteric reflex; however, it should be noted that the presence of absence of the cremasteric reflex is not as sensitive as once thought. Additionally, the cremasteric reflex is unreliable in young patients, especially those less than one year old.
Torsion of the testicular appendages are more common and not dangerous. During early onset, this may be differentiated from testicular torsion by maximal tenderness to palpation near the head of the epididymis or testis, an isolated tender nodule, and/or a blue dot appearance on the testis. The characteristics blue dot is due to the cyanotic torsed appendage. The testicular appendage tends to calcify and degenerate over two weeks, and typically no surgical intervention is required.
Other differential diagnoses to be considered are epididymitis, orchitis, inguinal hernia, symptomatic hydrocele, testicular necrosis of other etiology, and scrotal hematoma.
Ultrasound is the primary diagnostic modality beyond physical exam. Ultrasound for testicular torsion is approximately 93% sensitive and 100% specific. Trained sonographers should perform this exam in a timely manner. The point-of-care ultrasound technique to evaluate the testicle involves the high-frequency transducer (5 to 10 MHz), ample ultrasound gel, and proper patient positioning. The process is described in brief below:
Color flow doppler must be applied to both the affected and unaffected testicle of the patient. Begin with the unaffected testicle to gain a sense of what normal vascular flow looks like in this particular patient. Power Doppler is useful in the evaluation of testicular vascular flow as well. Power Doppler has a greater sensitivity for vascular flow, but does not allow the examiner to discern between arterial and venous flow.
Doppler can be employed to evaluate for both venous and arterial flow by placing the Doppler gate on areas of vascular flow and evaluating for both venous and arterial Doppler waveforms. Arterial waveforms will have large spikes due to the peaks of arterial blood pressure whereas venous waveforms appear typically as plateaus of Doppler flow. Applying Doppler and checking for both venous and arterial flow can further demonstrate the severity of the torsion. The same technique will be employed on the affected testicle.
Assessment for pyuria with urineanalysis is typically part of the acute scrotal pain workup. The presence of pyuria is consistent with epididymitis, orchitis, or urinary tract infection but does not rule out the possibility of testicular torsion. 
Ultrasound is not a perfect test for testicular torsion, especially in the very young. For example, 40% of neonatal testicles may have no apparent color flow doppler. If the clinical concern is high, seek urologic surgery consultation immediately. Any delay in treatment could result in testicular necrosis and loss. The typical window of opportunity for surgical intervention and testicular salvage is 6 hours from onset of pain. Therefore, early urologic surgery consultation upon presentation may be critical even in the absence of confirmatory testing.
Manual detorsion should be attempted if urological intervention is not immediately available. The abnormal testicle should be rotated in a medial to lateral direction (open book) 180 degrees and then evaluated for pain relief. If the pain is increased, consider rotating the testicle in the opposite direction. Ultrasound also can be used serially to evaluate for return of blood flow at the bedside. If unsuccessful, further manual detorsion may be attempted as the testicle can twist 1080 degrees.
Ultrasound is a sensitive and specific test for the evaluation of testicular torsion. Early urology involvement is crucial to avoid testicular loss. The use of color flow is essential in the evaluation of testicular torsion.
Testicular torsion is a surgical emergency that almost always presents to the emergency department. The first person to encounter the patient is the triage nurse who must be familiar with the symptoms of the disorder. Time is of the essence and the nurse should quickly notify the ER physician, who should consult with a radiologist for the appropriate test. The urologist is usually required to perform the surgery. The nurse should educate the family and the patient about the potential complications, including loss of the testis and infertility. The nurse should ensure that the patient is administered no food or drink by mouth and have the patient prepared to go for urgent surgery. More important, the nurse should avoid giving any pain medications until the patient has been seen by the urologist- or the pain medication will mask the symptoms and delay the diagnosis. Only through a systemic approach to diagnosis and treatment, is salvage of the testis a possibility. (Level V)
The outcomes of testicular torsion depend on when the patient presents to the ER and how quickly the diagnosis is made and treatment undertaken. Delays in diagnosis and treatment always lead to testicular atrophy. About 20-40% of cases of testicular torsion result in an orchiectomy. The risk of losing a testis is much higher among African Americans and younger males. For those who present within the first 6 hours of symptoms, the salvage rate is nearly 100% but this number quickly drops to less than 50% if the delay in seeking help is more than 12-24 hours. More important, when the testis is fixed by orchiopexy, there is also a potential for future torsion. (Level V)
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