This answer is: d) Left testicle abnormal, missed testicular torsion.

Acute scrotal pain is a fairly common clinical presentation for male adolescents and young adults. The differential diagnosis may include testicular torsion, infection (epididymitis, epididymo-orchitis, orchitis), torsion of the appendix testis, trauma, hernia, hydrocele, varicocele and segmental testicular infarction (seen in association with acute epididymoorchitis, polycythemia, sickle cell disease, hypersensitivity angiitis, Wegener’s granulomatosis, and following pelvic surgery, especially repair of scrotal hernias). Of all of these potential diagnoses, by far the most important is acute testicular torsion, as it can be treated successfully with urgent exploratory surgery. Figure 1a reveals a lack of colour Doppler flow within the left testicle, diagnostic of torsion. Testicular torsion is considered a surgical emergency because the likelihood of testicular salvage decreases as the duration of torsion increases (6 hours is commonly utilized as the cut-off point for organ salvage, from onset on acute scrotal pain). The physical exam should include inspection and palpation of the abdomen, testicles, epididymis, scrotum and inguinal regions. Urinalysis should always be performed, and scrotal imaging can be extremely useful when the diagnosis remains unclear. Scrotal ultrasound is the primary imaging modality of choice used to diagnose disorders of the scrotum and its contents. The combination of excellent anatomic visualization and colour Doppler flow analysis of real time blood flow allows accurate assessment of most disease entities in this body region.

Torsion of the testes results from a number of anatomical congenital abnormalities that allow the testis to rotate freely in the scrotal sac. The term is actually a misnomer of sorts, since the condition actually results from twisting of the spermatic cord, with secondary compromise of the testicular circulation. Testicular torsion has its peak incidence at puberty and during the neonatal period. Patients suspected of presenting with acute torsion of the testis should go immediately to surgical exploration, as the salvage rate is 70-100% within 6 hours of pain onset, but drops to 20% at 6-12 hours, with a negligible chance of salvage after 12 hours. Surgery is still indicated after 12 hours, to relieve pain and prevent infection.

Ultrasound imaging of acute torsion should be reserved for those cases in which the differential diagnosis is equivocal, since as stated above, those patients with a high index of suspicion for torsion should go directly to surgery. Unilateral absent flow with spectral Doppler sonography is the most accurate sign of acute testicular torsion. Intermittent or incomplete torsion, however, may result in false-negative studies, with some blood flow evident, and not deter the referring urologist to proceed with surgical exploration in suspected cases. Although some peripheral blood flow can be seen in the torsed testis, the presence of central flow is a strong negative predictor.

On the initial clinical assessment, the onset and duration of pain is a key factor in determining the initial most likely diagnosis. The pain associated with testicular torsion usually begins abruptly, as if a switch has been turned on. The pain is severe, and the patient often appears uncomfortable. Moderate pain developing gradually over a few days is more suggestive of epididymitis or testicular appendiceal torsion. With either of these conditions, the patient may appear relatively comfortable, except when examined.

Epididymitis, epididymo-orchitis and orchitis are usually the result of descending infection from a concomitant urinary tract infection. In young males, the most common pathogens include gonococcus and Chlamydia organisms. Ultrasound in epididymo-orchitis often shows an enlarged inhomogeneous hypoechoic testicle and epididymis with moderately to markedly increased colour Doppler flow. Cases of suspected epididymo-orchitis should be investigated with pelvic and scrotal ultrasound and consideration for a voiding cystourethrogram to rule out a pre-existing structural anomaly (which are present in almost all cases of UTI in prepubertal boys). Although option a) could be considered in the case presented, the amount of flow revealed in Figure 1b is actually normal, and the answer does not take into account the lack of flow in the left testicle (Figure 1a), which of course is the main finding.

Testicular tumours can be difficult to distinguish from benign entities; however, testicular tumours are a very uncommon cause of acute scrotal pain. Most large and infiltrative tumours are hypervascular (increased colour Doppler flow). Testicular tumours are the most common neoplasms in men aged 20-35 years. Approximately 95% of those are germ cell tumours. Seminomas are the most common germ cell tumours, comprising at least 40% of cases. The ultrasound appearance and presentation is not in keeping with seminoma in the patient presented.

The appendix testis is a mullerian duct remnant located at the superior pole of the testicle. It’s a common cause of acute scrotal pain when this small appendage undergoes torsion. Torsion of the appendix testis produces pain similar to that experienced with testicular torsion, but the onset is more gradual. Colour Doppler ultrasonography demonstrates increased blood flow, compared to the lack of blood flow seen with testicular torsion. On examination, there’s a tiny exquisitely tender palpable mass at the upper pole of the testicle, which may exhibit a focal bluish appearance on the skin in the early stage (“the blue dot sign” — bearing no relation to the colour Doppler exam). This condition is treated conservatively with non-steroidal anti-inflammatories, and scrotal support, as needed. This diagnosis should not be considered in the boy presented.

When presented with a patient with acute scrotal discomfort in the office or in the ER, the first steps are to take a history, physical and urinalysis. If the pain came on acutely, with duration of less than 6 hours, urological consultation with surgical exploration is likely required. In those with longer duration of symptoms and/or positive urinalysis, colour Doppler sonography is the next step. If the ultrasound reveals absent blood flow or equivocal results, surgical exploration should still be considered for missed or partial torsion. With cases of normal or increased blood flow on the symptomatic side, conservative management is indicated.

References:

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