What is an Inguinal Hernia?
An inguinal hernia occurs when abdominal contents—most commonly intestine—protrude through a weakness or defect in the abdominal wall muscles in the groin area, creating a visible or palpable bulge that typically increases with activities that raise intra-abdominal pressure. 1
Underlying Mechanism
In infants and children, inguinal hernias result from incomplete closure of the processus vaginalis, which is a peritoneal outpouching that normally closes after testicular descent, leaving a patent communication between the abdominal cavity and the groin through which abdominal organs can herniate. 1
In adults, hernias develop from acquired weakness in the abdominal wall muscles or connective tissue membranes in the inguinal region, allowing organs or tissue to escape through this defect. 2
The hernia can contain various abdominal structures, though small intestine is most common; less frequently, the appendix, cecum, or transverse colon may herniate into the inguinal canal or scrotum. 3
Who Gets Inguinal Hernias
Males are predominantly affected, with more than 90% of pediatric inguinal hernias occurring in boys. 1
The incidence in term infants is approximately 3-5%, rising to 13% in premature infants born before 33 weeks gestation. 1, 4
In pediatric cases, 60% occur on the right side, and bilateral involvement (contralateral patent processus vaginalis) occurs in 64% of infants younger than 2 months. 1
Adults of all ages can develop inguinal hernias, though they are more common in males across all age groups. 5
How It Presents
Patients typically notice a bulge or swelling in the groin that may extend into the scrotum in males or the labia in females. 1
The bulge characteristically increases with crying, coughing, straining, or physical activity—any maneuver that raises intra-abdominal pressure. 1
The bulge often disappears when lying down or can be manually reduced when the patient is in the prone position. 5
Symptomatic patients experience groin pain that can range from mild discomfort to severe pain, often described as burning, gurgling, or aching. 5
A heavy or dragging sensation in the groin typically worsens toward the end of the day and after prolonged activity. 5
The "silk sign" is pathognomonic: scrotal contents visibly retract inward with coughing or straining as increased intra-abdominal pressure forces herniated contents back through the inguinal canal. 1
Critical Complications to Recognize
Incarceration and strangulation are life-threatening complications that require emergency intervention. 1
Warning signs of strangulation include: irreducibility of the hernia, tenderness over the bulge, redness or warmth of the overlying skin, and systemic symptoms suggesting bowel compromise. 1
Signs of systemic inflammatory response syndrome (SIRS) commonly indicate strangulated obstruction. 1, 4
Delayed treatment beyond 24 hours significantly increases mortality rates, and symptomatic periods exceeding 8 hours substantially affect morbidity. 1, 4
In infants, the risk includes not only bowel incarceration but also gonadal infarction and testicular atrophy. 1
Why Surgical Repair is Necessary
All inguinal hernias in infants require surgical repair to prevent bowel incarceration and gonadal complications, with urgent referral recommended within 1-2 weeks of diagnosis. 1
In adults, while watchful waiting may be reasonable for asymptomatic or minimally symptomatic hernias in men, it is not recommended for symptomatic hernias or in nonpregnant women. 6
The goal of repair is to prevent complications that would necessitate emergency surgery with significantly higher complication rates. 1