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

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 features

• Main presentation is a midline lump