Paediatric Urology

8. ACUTE SCROTUM

8.1. Epidemiology, aetiology and pathophysiology

Acute scrotum is a paediatric urological emergency, most commonly caused by torsion of the testis or appendix testis, or epididymitis/epididymo-orchitis [261-266]. Other causes of acute scrotal pain are idiopathic scrotal oedema, mumps orchitis, varicocele, scrotal haematoma, incarcerated hernia, appendicitis or systemic disease (e.g. Henoch-Schönlein purpura) [267-279]. Trauma can also be a cause of acute scrotum, as it can relate to post-traumatic haematomas, testicular contusion, rupture dislocation or torsion [280-285]. Scrotal fat necrosis has also been reported to be an uncommon cause of mild-to-moderate scrotal pain in prepubertal overweight boys after exposure to cold [286].

This chapter discusses testicular torsion and epididymitis, while recurrent epididymitis is discussed in the chapter dealing with infections. Torsion of the testis occurs most often in the neonatal period and around puberty, whereas torsion of the appendix testis occurs over a wider age range.

Epididymitis affects two age groups: less than one year and twelve to fifteen years [287,288]. One study predicted the annual incidence of epididymitis at around 1.2 per 1,000 children [289]. Perinatal torsion of the testis (PTT) most often occurs prenatally. Bilateral torsion comprises 11-21% of all perinatal cases [290,291]. Most cases are extravaginal, in contrast to the usual intravaginal torsion, which occurs during puberty.

8.2. Diagnostic evaluation

Patients usually present with scrotal pain, except in neonatal torsion. The sudden onset of severe pain in combination with a vagal reaction (e.g. nausea, vomiting) is typical for torsion of the testis or appendix testis [292,293]. As the probability of irreversible changes and subsequent necrosis in testicular torsion is time-dependent with a critical window of approximately four to six hours, prompt diagnosis is essential [294].

In general, the duration of symptoms is shorter in testicular torsion (69% present within twelve hours) and torsion of the appendix testis (62%) compared to epididymitis (31%) [263,264,288].

In the early phase, location of the pain can lead to diagnosis. Patients with acute epididymitis experience a tender epididymis, whereas patients with testicular torsion are more likely to have a tender testicle, and patients with torsion of the appendix testis feel isolated tenderness of the superior pole of the testis [288].

An abnormal (horizontal) position of the testis is more frequent in testicular torsion than epididymitis [263]. Looking for absence of the cremasteric reflex is a simple method with 100% sensitivity and 66% specificity for testicular torsion [287,293]. Elevation of the scrotum may reduce complaints in epididymitis, but not in testicular torsion (Prehn Sign). Testicular torsion can also occur in undescended testes [295].

Fever occurs more often in epididymitis (11-19%). The classical sign of a ‘blue dot’ was found only in 10-23% of patients with torsion of the appendix testis [262,263,287,296]. In many cases, it is not easy to determine the cause of acute scrotum based on history and physical examination alone [261-266,287,296]. A positive urine culture is only found in a few patients with epididymitis [265,287,296,297]. It should be remembered that a normal urinalysis does not exclude epididymitis. Similarly, an abnormal urinalysis does not exclude testicular torsion.

The urological history and clinical findings can be used for risk-scoring to expedite the diagnostic process to identify testicular torsion as exemplified by the Testicular Workup for Ischemia and Suspected Torsion (TWIST) [298]. While risk-scoring systems such as TWIST may assist in streamlining decision-making, they do not conclusively prove or refute the diagnosis of testicular torsion and should not be solely relied upon. Incorporating scoring systems into the assessment can help reduce potential delays, although current evidence does not provide definite support from a medicolegal standpoint for conclusive decision-making [299-301]. Nevertheless, it may be prudent to consider lowering thresholds for intervention within the scoring systems in settings with limited diagnostic facilities.

Doppler US is useful to evaluate acute scrotum, with 63.6-100% sensitivity and 97-100% specificity, a positive predictive value of 100% and negative predictive value of 97.5% [302-307]. The use of Doppler US may reduce the number of patients with acute scrotum undergoing scrotal exploration, but it is operator-dependent and can be difficult to perform in prepubertal patients [304,308]. It may also show a misleading arterial flow in the early phases of torsion and in partial or intermittent torsion. Of key importance, persistent arterial flow does not exclude testicular torsion. In a multicentre study of 208 boys with torsion of the testis, 24% had normal or increased testicular vascularisation [304]. A comparison with the other side should always be done. Point-of-care US (POCUS) in emergency settings performed by the treating physician shows high sensitivity and specificity for testicular torsion in a systematic review, however, a risk of bias persists in the baseline studies [309]. Nevertheless, POCUS can aid in streamlining the diagnostic process.

Better results were reported using high-resolution US (HRUS) for direct visualisation of the spermatic cord twist with a sensitivity of 97.3% and specificity of 99% [304,310]. This should be done without inordinate delays for emergency intervention [296].

The diagnosis of acute epididymitis in boys is mainly based on clinical judgement and adjunctive investigation. However, it should be remembered that findings of secondary inflammatory changes in the absence of evidence of an extra-testicular nodule by Doppler US might suggest an erroneous diagnosis of epididymitis in children with torsion of the appendix testes [311]. Prepubertal boys with acute epididymitis have an incidence of underlying urogenital anomalies of 29.1% [312]. Complete urological evaluation in all children with acute epididymitis is still debatable [265,287,289].

8.3. Management

8.3.1. Epididymitis

In prepubertal boys, the aetiology is usually unclear, with an underlying pathology in about 25%. A urine culture is usually negative, and unlike in older boys, a sexually transmitted disease is very rare.

Antibiotic treatment, although often started, is not indicated in most cases unless urinalysis and urine culture show a bacterial infection [289,313,314]. Epididymitis is usually self-limiting and with supportive therapy (i.e. minimal physical activity and analgesics) heals without any sequelae. However, bacterial epididymitis can be complicated by abscess or necrotic testis, in which case surgical exploration might be required [315].

8.3.2. Testicular torsion

Surgical exploration is necessary in the setting of testicular torsion. If testicular torsion is confirmed, contralateral orchiopexy is commonly performed as well [316]. This should not be done as an elective procedure, but rather immediately following detorsion. One study reported residual torsion during exploration in 17 out of 53 patients, including 11 patients who had reported pain relief after manual detorsion [317,318]. Manual detorsion of the testis can be attempted in the ER while awaiting surgery and should not delay surgery [319]. Manual detorsion should be done using outward rotation of the testis unless the pain increases or if there is obvious resistance. Success is defined as the immediate relief of all symptoms and normal findings at physical examination [317]. Doppler US may be used for guidance [320].

Torsion of the appendix testis can be managed nonoperatively with the use of anti-inflammatory analgesics. During the six-week follow-up, clinically and with US, no testicular atrophy was revealed. Surgical exploration is done in equivocal cases and in patients with persistent pain [307].

8.3.3. Surgical treatment

Testicular torsion is an urgent condition that requires prompt surgical treatment. The two most important determinants of early salvage rate of the testis are the time between onset of symptoms and detorsion, and the degree of cord twisting [294]. Severe testicular atrophy occurred after torsion for as little as four hours when the turn was > 360°. In cases of incomplete torsion (180-360°) with symptom duration up to 12 hours, no atrophy was observed. However, an absent or severely atrophied testis was found in all cases of torsion > 360° and symptom duration > 24 hours [321].

Early surgical intervention with detorsion (mean torsion time less than 13 hours) was found to preserve fertility [322] and could also avoid testicle loss in a relevant portion of patients [295]. Urgent surgical exploration is mandatory in all cases of testicular torsion within 24 hours of symptom onset. In patients with testicular torsion > 24 hours, semielective exploration is necessary [294,321]. There is still controversy regarding whether to carry out detorsion and to preserve the ipsilateral testis, or to perform an orchiectomy, to preserve contralateral function and fertility after testicular torsion of long duration (> 24 hours). A study found that sperm quality was preserved after orchiectomy and orchidopexy in comparison to normal control men, although orchiectomy resulted in better sperm morphology [323,324]. However, larger testicular volumes have been associated with enhanced testicular function, suggesting a conservative approach to preserving the affected testicle unless it is unequivocally necrotic [325]. Although Sertoli cell function depends primarily on the contralateral testis, the torsed testicle may contribute to endocrine function.

Recurrence after orchidopexy is rare (4.5%) and may occur several years later. There is no consensus recommendation regarding the preferred type of fixation and suture material [316,326]. Incision of the tunica albuginea with tunica vaginalis graft to prevent or treat compartment syndrome has also been suggested [327], however, immediate effect on intratesticular pressure is vague with unclear long-term benefits [328].

Metachronous contralateral torsion may occur in perinatal testicular torsion. Therefore, early but not acute exploration of both testes with fixation is recommended [290,291,329].

8.4. Follow-up

Patients require follow-up mainly for fertility issues and hormonal consequences. Despite timely and adequate detorsion and fixation of the testicle, up to half of the patients may develop testicular atrophy, even when intraoperatively assessed as viable, and should be counselled accordingly [330].

8.4.1. Fertility

The results vary and are conflicting. In one study, unilateral torsion of the testis seriously intervened with subsequent spermatogenesis in approximately 50% of the patients and produced borderline impairment in another 20% [331]. Although, 30% of affected testicles with mumps orchitis show a degree of atrophy, long-term outcome in terms of fertility is not conclusive [332].

A study showed a normal pregnancy rate after unilateral testicular torsion, with no difference between the patients undergoing orchidopexy and those after orchidectomy [329].

8.4.2. Subfertility

Subfertility is found in 36-39% of patients after torsion. However, in a limited series, paternity and health-related quality of life (QoL) appear to be unaffected in patients as compared to age-matched controls in a long-term follow-up study [334]. Semen analysis may be normal in only 5-50% in long-term follow-up [294]. Early surgical intervention (mean torsion time less than 13 hours) with detorsion was found to preserve fertility, but prolonged torsion period (mean 70 hours) followed by orchiectomy jeopardised fertility [322].

Subfertility and infertility are consequences of direct injury to the testis after the torsion. This is caused by the cut-off of blood supply, but also by postischaemic-reperfusion injury that is caused after the detorsion when oxygen-derived free radicals are rapidly circulated within the testicular parenchyma [294].

8.4.3. Androgen levels

Even though the levels of FSH, luteinising hormone (LH) and testosterone are higher in patients after testicular torsion compared to normal controls, endocrine testicular function remains in the normal range after testicular torsion [323,325].