Abdominal Hernia

Hernia: an abnormal protraction of a cavity’s contents through a weakness in the wall of the cavity

Aetiology

Two factors usually required:

Structural weakness

  • Commonly in the body wall
  • Normal anatomical weakness e.g. diaphragm, umbilicus, inguinal/femoral canal
  • Abnormal weakness - congenital diaphragmatic hernia, inherited collagen disorders, surgical scars

Increased pressure

  • Repeated bouts of increased intra-abdominal pressure on that part of the body wall
    • Chronic cough
    • Pregnancy
    • Strenuous activity
  • Straining during bowel movements or urination

Pathophysiology

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Classification of hernias

  • Reducible: hernia can easily be pushed back into the abdomen
  • Incarcerated/irreducible hernia: when a hernia cannot be manipulated back to the abdomen
  • Strangulated hernia: vascular supply to the contents contained within the hernia is compromised, resulting in ischaemic and gangrenous tissue
    • Symptoms depend on organ involved

Epigastric hernia

  • Fascial defect in the linea alba between the xiphoid process and the umbilicus

Clinical presentation

  • Main presentation is a midline lump
  • Asymptomatic (75%) or can present with pain

Paraumbilical hernia

  • Found just above or just below umbilicus
  • Risk factors include stretching of the abdominal wall by obesity, multiple pregnancies and ascites

Clinical presentation

  • Frequently symptomatic presenting with pain
  • High incidence of incarceration and strangulation

Adult umbilical hernia

  • Usually results from persistent elevation of intraabdominal pressure

Clinical presentation

  • Frequently symptomatic presenting with pain
  • High incidence of incarceration and strangulation

Inguinal hernia

  • More frequent in males (12:1)
  • Right sided more common than left
  • Indirect (2/3) - patent processus vaginalis allows intestines to enter inguinal canal
  • Direct (1/3) - inguinal canal floor weakness e.g. pathological change in connective tissue

Clinical presentation

  • Groin swelling which usually disappears when lying down
  • Usually located above and medial to the pubic tubercle
  • Palpable cough impulse on examination

Investigation

  • Dynamic USS can be useful if there is doubt over diagnosis

Femoral hernia

  • Hernia passes through the femoral ring into the femoral canal
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Incisional hernia

  • Iatrogenic
  • Commonest complication of a laparotomy
  • Risk factors include morbid obesity, wound complications, inherited collagen abnormalities and advanced age

Spligelial hernia

  • Occur at the lateral edge of the rectus sheath, below and lateral to the umbilicus

Lumbar hernia

  • Occur on the posterolateral abdominal wall

Management

  • Conservative or surgical
  • Surgery usually indicated, especially if high risk of strangulation