- Clinical science
Abdominal hernias are defined as the abnormal protrusion of intra-abdominal contents through congenital/acquired areas of weakness in the abdominal wall. The four categories of anatomically-classified abdominal hernias include the following: ventral hernias (e.g., epigastric, umbilical, incisional hernias), groin hernias (inguinal and femoral hernias), pelvic hernias (obturator, sciatic, and perineal hernias), and flank/lumbar hernias. Groin hernias are discussed in more detail in their respective learning cards. Inguinal, incisional, and umbilical hernias are the most common types of hernias. Persistently raised intra-abdominal pressure (e.g., due to ascites, pregnancy, intra-abdominal tumors, chronic cough, etc.) increases the risk of developing an abdominal hernia. Uncomplicated hernias are asymptomatic, nontender, and completely reducible with an expansile cough impulse. Complicated hernias include incarcerated, obstructed, and strangulated hernias and are characterized by tenderness, irreducibility, features of bowel obstruction, and an absent cough impulse. Abdominal hernias are often diagnosed on clinical examination. Imaging (e.g., ultrasound, CT scan) is used to confirm the diagnosis and evaluate the contents of the hernia. Complicated hernias and those with a narrow neck (e.g., femoral hernia, obturator hernia, paraumbilical hernia) should be surgically repaired (primary repair/mesh repair). Congenital umbilical hernias typically close spontaneously by 5 years of age, have a wide neck, and a low risk of complications; surgical intervention is rarely necessary.
- Epigastric hernia: herniation through the linea alba, between the xiphoid process and the umbilicus
- Umbilical hernia: see below
- Incisional hernia: see below
- Spigelian hernia: a rare type of hernia that can occur anywhere along the ; most commonly below the (i.e., below the umbilicus)
- Parastomal hernia: herniation through a surgically created abdominal wall defect (i.e., a stoma)
Pelvic hernias (rare)
- Obturator hernia: herniation through the obturator foramen, especially the right side (since the sigmoid colon blocks the obturator canal on the left).
- Sciatic hernia: herniation through greater or lesser sciatic foramen
- Perineal hernia herniation through the pelvic floor
- Incisional hernias (see below)
- Lumbar hernias
Hernial contents completely return to the abdominal cavity through the abdominal wall defect on lying down or upon application of mild external pressure.
Most reducible hernias manifest as an asymptomatic nontender mass.
- Increases on straining (e.g., sitting up from a recumbent position)
- Decreases completely on lying down
- Visible cough impulse present: expansion of the hernia when the patient is asked to cough
- Edges of the fascial defect are palpable
- Bowel sounds may be heard over the mass (if the hernial content is bowel)
- Most reducible hernias manifest as an asymptomatic nontender mass.
Hernial contents become adhered to the hernial sac and cannot be reduced into the abdominal cavity.
- Irreducible nontender mass
- Visible cough impulse present
- May decrease partially on lying down
- Increased risk of obstruction and strangulation
- The abdominal wall defect acts as a tourniquet around the hernial contents, causing edema and distension of the hernial contents.
- Ischemia and necrosis of the hernial contents due to compromised vascular supply
The smaller the hernial orifice, the higher the risk of incarceration!
- Usually a clinical diagnosis
Imaging: indicated if the diagnosis is unclear and/or to identify contents of the hernial sac (e.g., loops of bowel)
- Ultrasound: especially useful to identify ventral hernias (e.g., epigastric, Spigelian, incisional, or umbilical hernia)
- IV and oral contrast enhanced CT scan: useful for suspected hernias that may be difficult to identify on physical examination (e.g., lumbar, obturator, perineal or sciatic hernia)
- Findings: abdominal wall defect with/without protrusion of intra-abdominal contents through it
- Abdominal x-ray
- Differential diagnosis of a ventral hernia
- Differential diagnosis of pelvic and groin hernias
- Differential diagnosis of a strangulated hernia
The differential diagnoses listed here are not exhaustive.
- Surgical hernia repair is recommended for the management of most abdominal hernias.
- Conservative management (observation) is indicated in:
- Definition: Herniation of intra-abdominal contents through an abdominal wall defect created during a previous abdominal surgery.
- Incidence: ∼15% of patients who have undergone abdominal surgery develop incisional hernias.
- Risk factors
- Clinical features
Conservative management is indicated in:
- Asymptomatic incisional hernias, with a wide neck;
- Patients who are at a high anesthetic risk (advanced age, multiple comorbidities)
- Surgery is indicated in symptomatic/complicated hernias or those with a narrow neck.
- Conservative management is indicated in:
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Risk of developing complications
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