Non-acute abdominal and urological problems in children

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51

Non-acute abdominal and urological problems in children

Introduction

The acute conditions described in Chapter 50 are largely congenital disorders presenting in the neonatal period, whereas non-acute conditions present across the whole of childhood. The most common referrals are hernias and associated problems, abnormalities of testicular descent and foreskin problems. Less often, surgeons manage chronic or recurrent abdominal pain, chronic constipation, rectal bleeding, an abdominal mass or rectal prolapse. Many children present first to a paediatrician and are referred to a paediatric or general surgeon.

Finally, a range of urological problems occur in infancy and childhood. Most are unique to young patients and are usually dealt with by paediatric urologists. Congenital urological abnormalities are often diagnosed by ultrasound in the antenatal period.

Problems with the groin and male genitalia

Hernias and associated problems

The processus vaginalis normally closes spontaneously soon after birth. Persistence causes three common problems in boys: patent processus vaginalis (PPV), hydrocoele and inguinal hernia, which may all present as inguinal or scrotal swellings, usually in babies and pre-school children (Fig. 51.1).

Hydrocoele

Non-communicating hydrocoeles are mostly seen in neonates and young babies (Fig. 51.2). The usual type is a scrotal swelling resulting from incomplete reabsorption of fluid within the tunica vaginalis after closure of the processus vaginalis. There may be a separate hernia present. These so-called ‘primary hydrocoeles’ sometimes appear following a viral illness. Rarely, a secondary hydrocoele results from testicular trauma or torsion, epididymitis or a testicular tumour.

On examination, there is a fluid swelling surrounding a normal testis; the sac transilluminates brightly and the testis can be felt posteriorly (but note that neonatal bowel is thin and may also transilluminate brightly in a hernia). If this cannot be achieved, investigation needs to exclude a secondary hydrocoele. In inguinal hernia the examiner cannot ‘get above’ the swelling, i.e. the swelling originates in the groin; this is the cardinal feature. Hydrocoeles also occur in the spermatic cord (hydrocoele of the cord) or in the round ligament in girls where they are known as hydrocoeles of the canal of Nuck. Most hydrocoeles resolve between 18 and 24 months of age. A hydrocoele persisting beyond the age of 2 or appearing later may require surgery.

Inguinal hernia

Inguinal hernias in children arise because the processus vaginalis fails to close after testicular descent; they are true congenital abnormalities. Anatomically, they are the same as indirect inguinal hernias in adults (see Ch. 32) but without a substantial abdominal wall defect. The incidence in infants ranges from 1% to 4.4%, with a male preponderance of 4 : 1; 98% are indirect. The incidence in premature neonates is 30% and the overall incidence is increasing in line with the number of premature neonates surviving.

A hernia usually presents as a lump at the external inguinal ring, when the child cries or strains at stool, but then reduces spontaneously. When seen electively, there is often no abnormality, but most surgeons accept a parent’s clear history of a hernia and arrange surgery. With larger defects, a lump is constantly present and expands during crying. The urgency of hernia repair is governed by age; the older, the less likely it will become incarcerated (acutely irreducible). Infants at home should have hernias fixed on the next available operating list. Neonates and pre-term infants in hospital should have them fixed before discharge. Older children without episodes of incarceration can have hernias fixed electively.

Inguinal hernias may become acutely irreducible and painful, sometimes with obstructive symptoms such as vomiting (see Ch. 50). In these cases, there is a real risk of testicular necrosis and/or strangulation of the hernia contents, e.g. bowel or ovary (see Fig. 50.10). In known hernias, parents should be instructed to bring the child to hospital for urgent herniotomy if it becomes incarcerated to prevent these risks.

The standard operation is inguinal herniotomy, a common general paediatric operation. In babies and children, this involves separating the peritoneal sac from the cord (or round ligament), ligating it at the external ring and removing it. There is rarely any need to perform a repair (herniorrhaphy); see Figure 51.3. The incidence of an undiagnosed contralateral hernia in boys is between 1 : 8 and 1 : 13 but contralateral groin exploration is no longer performed in the UK.

Umbilical hernia

Many newborn babies have umbilical hernias, particularly if premature (Fig. 51.4), but the defect usually cicatrises and resolves during the first 2 years of life; they are common in Afro-Caribbean babies and can run strongly in families. Small umbilical hernias may undergo spontaneous closure up to 4–5 years of age. Rarely, they become incarcerated or strangulate. Indications for repair are symptoms, persistence beyond 5 years and perhaps social pressure to prevent teasing. The size of the abdominal wall defect should be determined; large defects (> 2 cm) are less likely to close spontaneously, although very large swellings may have small abdominal wall defects likely to close spontaneously. It is important to differentiate umbilical hernias from epigastric hernias which do not close spontaneously. At operation, a small subumbilical ‘smile’ incision allows emptying and ligation of the peritoneal sac and placement of a few absorbable repair sutures. The umbilical skin is usually sutured to the repair to restore its normal recessed appearance.

Testicular maldescent

There are several terms for testes not fully descended into the scrotum; undescended is inaccurate in that most missing testes started along the normal pathway and arrest in the inguinal region, a few descended to the wrong place and a few are missing altogether. The terms maldescended or incompletely descended cover all but the truly absent testis. Clinically, one or both testes fail to reach the scrotum in 3% of full-term newborn males, but much higher rates with prematurity. Full descent has occurred in most boys by the age of 3–6 months, leaving about 1.6% with maldescended testes and these rarely descend later because androgen levels are highest in the first few months and then fall to very low levels until puberty.

The normal mechanism of descent is not fully understood but does occur in two phases. Migration from the gonadal ridge to the internal inguinal ring depends on shortening of the gubernaculum, driven by Müllerian inhibiting substance (MIS). This phase is not androgen-dependent, unlike the second phase of descent from internal ring to scrotum. A maldescended testis may arrest anywhere on its path of descent. About 20% lie within the abdomen but 80% lie in the groin area, in the inguinal canal or usually outside the external ring in the superficial inguinal pouch or upper scrotum. In addition, 1% of testes are deflected and lie ectopically. Second phase maldescent can result from the testis being structurally abnormal, rather than any abnormality being caused by maldescent. The common sites of incomplete descent or ectopia are shown in Figure 51.5.

The main concerns with maldescended testes are the risks of malignancy, subfertility, and torsion or trauma in an abnormal position; cosmetic appearance and psychological impact of cryptorchidism has a bearing in later life:

• Neoplasia—carcinoma-in-situ is present in 2% of undescended testes and maldescent has up to 10 times the normal risk of testicular malignancy (although the risk is still small); if surgical correction is done sufficiently early, it may reduce this risk but the principal purpose is for the patient to perform self-examination and report lumps in later life. Long-term follow-up after orchidopexy is desirable. Seminomas are the most common tumour (60%) and usually present between 20 and 40 years of age. It is important to inform the parents of the increased risk of malignancy and to reinforce the importance of testicular self-examination in adult life

• Subfertility—maldescended testes exhibit incomplete maturation of seminiferous tubules, leading to sperm abnormal in quantity, form or motility. This may be by virtue of being at normal body temperature instead of at least 1° cooler in the scrotum. Early orchidopexy helps maturation of the tubules and spermatogenesis, ideally between 6 and 12 months of age. Patients with unilateral maldescent have more subfertility and lower sperm counts. Those with bilateral intra-abdominal testes have the most subfertility

• Torsion—incompletely descended testes are abnormally mobile. Torsion of the testis, actually torsion of the spermatic cord, causes strangulation of blood supply, testicular necrosis and later atrophy. Torsion sometimes occurs during intrauterine life but may happen at any age. Intrauterine or neonatal torsion occurs proximal to the reflection of the tunica vaginalis (i.e. extravaginal). Infarction results in atrophy and loss of the testis so that at laparoscopy, only blind-ending testicular vessels and vas deferens are found. The condition occurs bilaterally in up to 30%

• Psychological—normal genitalia are important in the development of body image, gender acceptance and personality in adolescence. Orchidopexy at an early age provides reassurance to the child and parents

Boys should be examined regularly from birth right through school age to identify maldescent and allow timely orchidopexy. Periodic examination is needed because unequivocally descended testes can later ascend and parents and doctors should be alert to this possibility. There may be a fibrous band within the processus vaginalis preventing elongation of testicular vessels as the boy grows. The resulting ‘stationary’ testis appears to ascend, and no longer comes comfortably into the scrotum.

With a history of a missing testis, the chief point is whether the testis is palpable. If palpable at the scrotal neck, it should be gently manipulated into its correct position. If it then stays put, it is retractile and needs no treatment provided it become less retractile as the boy grows. If the testis immediately retracts, it is maldescended and needs treatment.

If the testis is impalpable, investigations should be undertaken to locate it. Laparoscopy is the investigation of choice; the testis may be found intra-abdominally or the cord may be seen entering the deep ring; in either case, the testis is mobilised and placed in the scrotum. Alternatively, a blind-ending spermatic cord may be found indicating the testis is missing, probably as a result of intrauterine torsion. No action is needed if this is unilateral but if bilateral, genetic screening is required and possible hormonal treatment and testicular prostheses.

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