Introduction

The acute scrotum is defined as a painful and/or enlarged scrotum and may be acute or subacute in onset. The origin of the pathology may be from the testis, the groin or the scrotal skin. In a younger child, the pain will cause the child to be unsettled with crying, and it may be intractable. In an older child, the reluctance to ambulate may be a predominant feature. In addition, referred pain from a sore testis may present as abdominal pain. Therefore, in patients presenting with abdominal (especially lower-abdominal) pain one must examine the inguinal scrotal region so as not to overlook torsion of a testicle.

The diffuse vasculitis of Henoch–Schönlein purpura may affect the testis and/or scrotum. Usually other manifestations of the condition such as a skin rash or haematuria are present. A radionuclide scan may assist in differentiating this condition from torsion of the testicle.

Torsion of a testicular or epididymal appendage

Appendages of the testis and epididymis occur in 90% of testicles. Torsion of these appendages is the most common cause of testicular pain. The most common age of presentation is at the onset of puberty and this is thought to be due to the release of oestrogens and androgens from the male adrenal gland stimulating the appendages and causing them to enlarge. As the appendages are on a narrow stalk they have a tendency to twist.¹ Oedema of the appendages may also occur following trauma to the testis. Onset of the pain is usually gradual and the child is often able to ambulate without difficulty. Redness and swelling of the scrotum are also mild in the first 24 hours but may increase to an alarming degree in the following days and appearances can then be similar to those of testicular torsion. The scrotal swelling is often due to a small secondary hydrocele. The testis is usually normally aligned and in normal position in the scrotum. Tenderness is maximal at the upper pole of the testis (where the appendage is located) and a blue dot may be seen through the skin at the upper pole consistent with an infarcted appendage.

Torsion of the testis

This is an acute emergency and is due, in most situations, to medial rotation of the spermatic cord. However, in one-third of cases the testis rotates in a lateral direction.² The torsion usually occurs spontaneously. However, sometimes it can follow direct trauma to the testis. The pain is likely to be acute and severe and may be associated with nausea or vomiting. The older child is often reluctant to ambulate. Often there is a history of previous short-lived pain in a testis consistent with intermittent episodes of spontaneously resolving torsion. The testis is usually enlarged and in a high position in the scrotum or even in the groin. It is not usually in its normal lie and there is much redness and swelling of the scrotal skin. Usually a secondary hydrocele is present. The contralateral testicle may lie in a bell-clapper fashion owing to the insertion of the epididymis in the central part of the testicle and this in turn predisposes the testicle to undergo torsion. The child should be taken to the operating theatre urgently, even if the child is not adequately fasted, as prolonged obstruction of the testicular vessels may lead to partial or complete atrophy of the testicle. Therefore nuclear scans and colour Doppler ultrasound should be avoided if the diagnosis is clear, as these investigations may result in unnecessary delay and they are not reliable. False negatives and false positives have been reported with both modalities. Colour Doppler ultrasonography may be misleading as intratesticular flow may be seen even in testicles that have undergone torsion.³ Visualisation of a twist in the cord is more reliable.⁴ Survival of the testicle will depend on the number of twists that the spermatic cord has undergone, along with the length of time that the cord has been twisted, with the prognosis being excellent for those undergoing surgery within 6 hours of the onset of symptoms.^5,6

Epididymo-orchitis

Infection or inflammation may affect the epididymis or the testis. Infections in the epididymis may arise from retrograde flow along the vas deferens or lymphatics from urinary tract infections, or from the bloodstream. Inflammation of the testis may arise from conditions such as mumps. The epididymis is tender and swollen and the testis also may be tender. The testis is of normal lie and in a normal position in the scrotum. A raised interleukin-6 level may be clinically helpful in assisting the diagnosis of epididymitis.⁷ Once the diagnosis has been confirmed the child’s urine should be sent for analysis and he should then be commenced on antibiotics. Enteric organisms are the usual cause of the urinary tract infection.⁸ Once the condition has resolved renal ultrasound and micturating cystourethrogram should be performed as the urine infection may have resulted from an abnormality in the urinary tract, such as posterior urethral valves.⁹

Idiopathic scrotal oedema

The cause of this condition is unknown. The child presents with scrotal discomfort, oedema and erythema of one side of the scrotum, which may spread to affect the entire scrotum, the penis and inguinal and perineal regions. The testis is not swollen and is normally aligned and the tenderness arises from the palpably thickened scrotal wall. Occasionally, eosinophilia may occur and, characteristically, ultrasound examination shows marked thickening of the scrotal wall, increased peri-testicular blood flow and a mild reactive hydrocele.¹⁰ The condition resolves in 1–4 days and no treatment, apart from pain relief, is required.