What is an Umbilical Hernia?
An umbilical hernia is a protrusion of intraabdominal contents (preperitoneal fat, omentum, or bowel) through a fascial defect at the umbilical ring, resulting from incomplete closure or weakness of the abdominal wall at this location. 1, 2
Anatomical Basis
The umbilical hernia develops due to structural weakness at the umbilical ring where the fascia posterior to the umbilical canal is inherently thinner, creating a vulnerable area. 1 This defect allows abdominal contents to protrude through:
- Congenital (direct) hernias occur through the area of fascial weakness itself 1
- Acquired (indirect) hernias develop through herniation within the umbilical canal 1
- The fascial defect can range from very small (<1 cm) to large/complex hernias 3
Epidemiology and Risk Factors
The incidence varies significantly by population:
- Pediatric population: 1.9% to 18.5% in white populations 1
- Adult risk factors include female gender, obesity, and ascites 4
- Patients with cirrhosis and ascites have particularly high complication rates 5
Clinical Presentation
Most umbilical hernias are asymptomatic, presenting as a visible bulge at or lateral to the umbilicus. 1, 2 However, complications can occur:
Potential Complications
- Incarceration: hernia contents become irreducible and trapped 6, 5
- Strangulation: compromised blood supply to hernia contents, requiring emergency intervention 6, 5
- Bowel obstruction: when intestinal contents are involved 6, 4
- Intermittent umbilical or abdominal pain 1
- Skin ulceration or necrosis over the hernia (rare but serious) 5
- Rupture with evisceration (extremely rare) 1
Warning Signs Requiring Immediate Attention
Patients must be monitored for signs indicating emergency surgical intervention: 5
- Inability to reduce the hernia
- Redness or discoloration of skin over the hernia
- Nausea or vomiting
- Severe pain suggesting ischemia
Systemic inflammatory response syndrome (SIRS), contrast-enhanced CT findings, and elevated lactate, serum creatinine phosphokinase (CPK), and D-dimer levels are predictive of bowel strangulation. 5
Natural History
In Children
The great majority of pediatric umbilical hernias close spontaneously without treatment. 1 Observation with periodic follow-up is appropriate in most cases, as incarceration and strangulation are uncommon in this population. 1
In Adults
Adult umbilical hernias do not spontaneously resolve and carry risk of complications, particularly in patients with obesity, ascites, or other comorbidities. 4
Common Pitfalls
- Umbilical hernias account for 15-25% of small bowel obstructions in adults, making them a significant cause of emergency presentations 6
- Each hernia orifice (including umbilical) should be carefully examined during evaluation of bowel obstruction 6
- Rare presentations include herniation of the appendix through an umbilical hernia, which can present as appendicitis 4
- In patients with cirrhosis and ascites, special attention is required due to higher complication rates 5