Genitalia

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Genitalia

Inguinoscrotal disorders

Embryology

The testis is formed from the urogenital ridge on the posterior abdominal wall close to the developing kidney. Gonadal induction to form a testis is regulated by genes on the Y chromosome. During gestation, the testis migrates down towards the inguinal canal, guided by mesenchymal tissue known as the gubernaculum, probably under the influence of anti-Müllerian hormone (Fig. 19.1a).

Inguinoscrotal descent of the testis requires the release of testosterone from the fetal testis. A tongue of peritoneum, the processus vaginalis, precedes the migrating testis through the inguinal canal. This peritoneal extension normally becomes obliterated after birth, but failure of this process may lead to the development of an inguinal hernia or hydrocele (Fig. 19.1b–d).

Inguinal hernia

Inguinal hernias in children are almost always indirect and due to a patent processus vaginalis. They are much more frequent in boys and are particularly common in premature infants. Hernias are more common on the right side. At least 1 in 50 boys will develop an inguinal hernia.

Inguinal hernias usually present as an intermittent swelling in the groin or scrotum on crying or straining. Unless the hernia is observed as an inguinal swelling (Figs 19.2, 19.3), diagnosis relies on the history and the identification of thickening of the spermatic cord (or round ligament in girls). The groin swelling may become visible on raising the intra-abdominal pressure by gently pressing on the abdomen or asking the child to cough.

An inguinal hernia in an infant may present as an irreducible lump in the groin or scrotum. The lump is firm and tender. The infant may be unwell with irritability and vomiting. Most ‘irreducible’ hernias can be successfully reduced following opioid analgesia and sustained gentle compression. Surgery is delayed for 24–48 hours to allow resolution of oedema. If reduction is impossible, emergency surgery is required because of the risk of strangulation of bowel and damage to the testis. A hernia associated with an undescended testis should be operated early to minimise risks to the testis.

Hydrocele

A patent processus vaginalis, which is sufficiently narrow to prevent the formation of an inguinal hernia, may still allow peritoneal fluid to track down around the testis to form a hydrocele (Fig. 19.4). Hydroceles are asymptomatic scrotal swellings, often bilateral, and sometimes with a bluish discoloration. They may be tense or lax but are non-tender and transilluminate. Some hydroceles are not evident at birth but present in early childhood after a viral or gastrointestinal illness. The majority resolve spontaneously as the processus continues to obliterate, but surgery is considered if it persists beyond 18–24 months of age. A hydrocele of the cord forms a non-tender mobile swelling in the spermatic cord.

Undescended testis

An undescended testis has been arrested along its normal pathway of descent (Fig. 19.5). At birth, about 4% of full-term male infants will have a unilateral or bilateral undescended testis (cryptorchidism). It is more common in preterm infants because testicular descent through the inguinal canal occurs in the third trimester. Testicular descent may continue during early infancy and by 3 months of age the overall rate of cryptorchidism in boys is 1.5%, with little change thereafter. Contrary to previous teaching, it is now recognised that occasionally a testis which is fully descended at birth can ascend to an inguinal position during childhood, accounting for some late-presenting ‘undescended’ or ‘ascended’ testes. This phenomenon may be due to a relative shortening of cord structures during growth of the child.

Classification

Investigations

Useful investigations include:

• Ultrasound – this has a limited role in identifying testes in the inguinal canal in obese boys but cannot reliably distinguish between an intra-abdominal or absent testis. It is performed in children with bilateral impalpable testes to verify internal pelvic organs.

• Hormonal – for bilateral impalpable testes, the presence of testicular tissue can be confirmed by recording a rise in serum testosterone in response to intramuscular injections of human chorionic gonadotrophin (HCG); these boys may require specialist endocrine review.

• Laparoscopy (Fig. 19.6) – the investigation of choice for the impalpable testis. Under anaesthesia, inguinal examination is first carried out to check that the testis is not in the inguinal canal.

Management

Surgical placement of the testis in the scrotum (orchidopexy) is undertaken for several reasons:

• Fertility – to optimise spermatogenesis, the testis needs to be in the scrotum below body temperature. The timing of orchidopexy is controversial, but orchidopexy during the second year of life may optimise reproductive potential. After 6 months of age descent of testis is unlikely and referral for paediatric surgical review at that age is recommended. Fertility after orchidopexy for a unilateral undescended testis is close to normal. In contrast, fertility is reduced to around 50% after bilateral orchidopexy for palpable undescended testes, and men with a history of bilaterally impalpable testes are usually sterile.

• Malignancy – undescended testes have histological abnormalities and an increased risk of malignancy. The risk is greater for bilateral undescended testes and the greatest risk is for testes which are intra-abdominal. Although the evidence is somewhat contradictory, some studies have suggested that early orchidopexy for a unilateral undescended testis reduces the risk to nearly the same as a normal testis. A scrotal testis can also be more easily self-examined than an inguinal or ectopic one.

• Cosmetic and psychological – if a testis is absent, a prosthesis can be used but this is best delayed until a larger adult-sized prosthesis can be inserted.

Surgery

Most boys with an undescended testis undergo an orchidopexy via an inguinal incision. The testis is mobilised, preserving the vas deferens and testicular vessels, the associated patent processus vaginalis is ligated and divided, and the testis is placed in the scrotal pouch. The operation is usually performed as a day-case procedure.

Most intra-abdominal testes are amenable to laparoscopic staged orchidopexy. Orchidectomy is considered in rare circumstances of a very high testis in an older child or a unilateral intra-abdominal testis in a postpubertal adolescent with a normal contralateral testis. Before conducting laparoscopy in a peripubertal boy, baseline abdominal ultrasound scan and serum tumour markers are checked. Although intra-abdominal testes have profoundly defective spermatogenesis, they are capable of producing male hormones.

The acute scrotum

Torsion of the testis

Testicular torsion is most common in adolescents but may occur at any age, including the perinatal period (Fig. 19.7). The pain is not always centred on the scrotum but may be in the groin or lower abdomen. Atypical presentation is not unusual and the testes must always be examined whenever a boy or young man presents with inguinal or lower abdominal pain of sudden onset (see Case History 19.1). There may be a history of previous self-limiting episodes. Torsion of the testis must be relieved within 6–12 h of the onset of symptoms for there to be a good chance of testicular viability. Surgical exploration is mandatory unless torsion can be excluded. If torsion is confirmed, fixation of the contralateral testis is essential because there may be an anatomical predisposition to torsion, for example the ‘bell clapper’ testis, where the testis is not anchored properly. An undescended testis is at increased risk of torsion and at increased risk of delayed diagnosis. It may also be confused with an incarcerated hernia. Expert Doppler ultrasound looking at flow in the testicular blood vessels may allow torsion of the testis to be differentiated from epididymitis, but should not be used to diagnose torsion as only early surgical correction may salvage the testis. If there is any doubt about the cause of a painful scrotum, surgery should be performed.

Other causes

Viral or bacterial epididymo-orchitis or epididymitis may cause an acute scrotum in infants and toddlers, and scrotal exploration is often necessary to confirm the diagnosis. If an associated urinary tract infection is present, antibiotic treatment and full investigation of the urinary tract will be required. Other conditions which may cause scrotal symptoms and signs are idiopathic scrotal oedema (usually painless, bilateral scrotal swelling and redness in a preschool child) or an incarcerated inguinal hernia.

Abnormalities of the penis

Hypospadias

In the male fetus, urethral tubularisation occurs in a proximal to distal direction under the influence of fetal testosterone. Failure to complete this process leaves the urethral opening proximal to the normal meatus on the glans and this is termed hypospadias (Fig. 19.10). This is a common congenital anomaly, affecting about 1 in every 200 boys. Recent studies suggest that the incidence is increasing.

Hypospadias consists of:

Glanular hypospadias may be a solely cosmetic concern, but more proximal varieties may cause functional problems including an inability to micturate in a normal direction and erectile deformity. With more severe varieties of hypospadias, additional genitourinary anomalies should be excluded and sometimes it is necessary to consider disorders of sexual differentiation.

Circumcision

At birth, the foreskin is adherent to the surface of the glans penis. These adhesions separate spontaneously with time, allowing the foreskin to become more mobile and eventually retractile. At 1 year of age, approximately 50% of boys have a non-retractile foreskin, but by 4 years this has declined to 10%, and by 16 years to only 1%. A non-retractile foreskin often leads to ballooning on micturition, which is physiological. Gentle retraction of the foreskin at bathtimes helps to maintain hygiene, but forcible retraction of a healthy non-retractile foreskin should be avoided.

Two conditions that require reassurance are preputial adhesions (when the foreskin remains partially adherent to the glans) and the presence of white ‘pearls’ under the foreskin due to trapped epithelial squames. Both conditions are usually asymptomatic and resolve spontaneously.

Circumcision is one of the earliest recorded operations and remains an important tradition in the Jewish and Muslim religions. Although routine neonatal circumcision is still common in some Western countries such as the USA, the arguments generally used to justify on medical grounds have been discredited and no national or international medical association currently advocates routine neonatal circumcision. Neonatal circumcision is not without risk of significant morbidity. Nevertheless, the issue is still hotly debated.

There are only a few medical indications for circumcision:

• Phimosis (Fig. 19.13). This term is often used to describe the inability to retract the foreskin. As described above, at birth the foreskin is non-retractile and phimosis is physiological. Pathological phimosis is seen as a whitish scarring of the foreskin and is rare before the age of 5 years. The condition is due to a localised skin disease known as balanitis xerotica obliterans (BXO), which also involves the glans penis and can cause urethral meatal stenosis

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Figure 19.13 Pathological phimosis.

• Recurrent balanoposthitis (Fig. 19.14). Single attack of redness and inflammation of the foreskin, sometimes with a purulent discharge, is common and usually responds rapidly to warm baths and a broad-spectrum antibiotic. Recurrent attacks of balanoposthitis (inflammation of the glans and foreskin) are uncommon and circumcision is occasionally indicated.

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Figure 19.14 Balanoposthitis.

• Recurrent urinary tract infections. Although urinary infection is more common in uncircumcised boys the overall incidence is low and routine circumcision is not justified as a preventative measure. However, circumcision may be helpful in reducing the risk of urinary tract bacterial colonisation in boys with upper urinary tract anomalies complicated by recurrent urinary infection. It may also be appropriate in boys with spina bifida who need to perform clean intermittent urethral catheterisation.

There is some data from countries with a high prevalence of HIV infection that the risk of transmission is lower in circumcised males.

Surgery

Circumcision for medical indications is performed under a general anaesthetic as a day case. During the procedure, a long-acting local anaesthetic block can be given to reduce postoperative pain. Circumcision is not a trivial operation. Healing can take up to 10 days, with discomfort for several days. Bleeding and infection are well-recognised complications, but more serious hazards, such as damage to the glans, may occur if the procedure is not carried out by appropriately trained personnel. The procedure also carries the risk of psychological trauma.

Preputioplasty can be offered as an effective alternative to circumcision in selected cases. After retraction of the foreskin, the tight preputial ring is incised longitudinally and then sutured transversely. Unlike circumcision, preputioplasty conserves the foreskin and results in less postoperative discomfort and fewer complications. However, regular retraction of the foreskin is required in the first few weeks after surgery and for this reason, preputioplasty is better suited to older boys who are willing to do this.

Genital disorders in girls

Vulvovaginitis/vaginal discharge

Vulvovaginitis and vaginal discharge are common in young girls. They may result from infection (bacterial or fungal), specific irritants, poor hygiene or sexual abuse, although none of these factors is present in most cases. Vulvovaginitis may rarely be associated with threadworm infestation. Parents should be advised about hygiene, the avoidance of bubble bath and scented soaps and the use of loose-fitting cotton underwear. Swabs should be taken to identify any pathogens, which can then be specifically treated. Salt baths may be helpful. Oestrogen cream applied sparingly to the vulva may relieve the problem in resistant cases by increasing vaginal resistance to infection as prepubertal tissues tend to be atrophic. If there are any concerns about sexual abuse, the child must be seen by a paediatrician (see Ch. 7). Rarely, if the vaginal discharge is persistent or purulent, examination under anaesthesia may be needed to exclude a vaginal foreign body or unusual infections.

Disorders of sexual differentiation are considered in Chapter 11.