A LUMP IN THE GROIN

The site and intermittent nature of the swelling make an inguinal hernia the most likely diagnosis. They are sometimes difficult to detect. Older children can increase their intraabdominal pressure by coughing, and examining them standing up may help. The position of the testes must be noted because, if retractile, they can be mistaken for a hernia. In girls the contents of the hernial sac are often adherent within the sac and hence not reducible – a sliding hernia – and a fallopian tube or ovary may be palpable. The commonest cause of a swelling in the groin is a lymph node, but they are usually small and mobile and lie more inferior and lateral than an inguinal hernia. They may also be confused with a retractile testis. An ultrasound can help. Direct and femoral hernias are rare in children. In adults, inguinal hernias are associated with a muscular weakness or defect, but in children they usually result from persistent patency of the processus vaginalis (PV). This accompanies the testis as it exits the abdomen and descends into the scrotum and is obliterated by, or soon after, birth. Failure of obliteration can occur anywhere along its length, explaining the range of presentations (see Fig. 33.1). A hydrocoele is fluid within the tunica vaginalis – the remnant of the PV that surrounds the testis. Hydrocoeles transilluminate. They usually resolve spontaneously by the age of 12 months and, if not, should be referred to a surgeon. Fifty per cent of inguinal hernias present in the first year of life, most by the age of 6 months.

Children at risk of inguinal hernia

• Preterm infants – especially those with very low birth weight (30 per cent affected)

• Boys – outnumber girls 6:1 because ovaries do not leave the abdominal cavity

• Infants with chronic lung disease

• Children with conditions associated with abnormal abdominal fluid or increased intra-abdominal pressure

• Children with developmental urogenital anomalies

• Infants with disorders of sexual differentiation – phenotypically female infants with inguinal hernias, especially bilateral, should be examined carefully to exclude complete androgen insensitivity syndrome, an extremely rare but crucial diagnosis

Treatment is surgical. Early repair reduces the significant risk of the contents of the sac becoming irreducible (incarceration) and/or the hernia becoming strangulated, i.e. so tightly constricted that the contents become ischaemic or gangrenous, with consequent testicular atrophy.

KEY POINTS

• The commonest cause of a lump in the groin is a lymph node

• Preterm infants are at high risk of developing an inguinal hernia

• Early repair of a hernia is important to reduce the risk of incarceration and/or strangulation