How to diagnose an inguinal hernia in an infant?

How to Diagnose an Inguinal Hernia in an Infant

Diagnose an inguinal hernia in infants by examining for an inguinal bulge that increases with crying or straining and may extend into the scrotum in males or labia in females. 1

Physical Examination Technique

Primary Diagnostic Maneuver

• Observe for a visible bulge in the groin area that becomes more prominent when the infant cries, strains, or increases intra-abdominal pressure. 1
• The bulge may extend into the scrotum in male infants or into the labia majora in female infants. 1
• In males, palpate the testis to ensure it is present in the scrotum and not involved in the hernia. 1

The Silk Sign

• Look for the "silk sign" or "silk glove sign" - a pathognomonic finding where scrotal contents retract inward on coughing or straining. 1
• This occurs when increased intra-abdominal pressure forces herniated contents back through the inguinal canal into the abdomen, creating a palpable impulse or visible retraction of the scrotal bulge. 1

Bilateral Examination

• Always examine both groins bilaterally, as contralateral patent processus vaginalis occurs in 64% of infants younger than 2 months. 1
• The side of the clinically detected hernia does not predict contralateral involvement. 2

When Physical Examination is Non-Diagnostic

Parent-Provided Digital Photographs

• If no bulge is detected during the office visit, request that parents photograph the bulge when it appears at home. 3
• Digital photographs are highly reliable for documenting the presence and laterality of inguinal hernias, with 100% operative confirmation in one study of 23 patients diagnosed solely by history and imaging. 3
• This approach avoids repeat office visits and saves considerable time and expense. 3

Critical Assessment for Complications

Signs of Incarceration or Strangulation (Require Emergency Intervention)

• Irreducibility of the hernia 1
• Tenderness over the hernia site 1
• Erythema (redness) or warmth of the overlying skin 1
• Systemic symptoms including fever, tachycardia, vomiting, or abdominal wall rigidity 1
• Leukocytosis or elevated lactate, CPK, and D-dimer levels 1

High-Risk Populations for Incarceration

• Females are at higher risk for incarceration and may present with ovarian hernias. 4
• Infants under 1 year of age are 60 times more susceptible to incarceration. 4
• Incarceration risk is approximately 13% in premature infants born before 33 weeks gestation. 5

Common Pitfalls to Avoid

• Do not miss femoral hernias, which have a higher risk of strangulation than inguinal hernias. 1
• Do not confuse inguinal hernias with hydroceles or undescended testes. 6 Hydroceles present as painless, fluctuant masses without the characteristic bulge that increases with crying. 7
• Do not delay evaluation if any signs of strangulation are present - symptomatic periods lasting longer than 8 hours significantly affect morbidity, and delayed treatment beyond 24 hours is associated with higher mortality rates. 1, 8

Immediate Management After Diagnosis

• All inguinal hernias in infants require urgent surgical referral for repair within 1-2 weeks of diagnosis to prevent life-threatening complications including bowel incarceration and gonadal infarction/atrophy. 1
• Infants under 3 months of age require urgent referral. 6
• Any hernia with signs of incarceration or strangulation requires emergency surgical intervention immediately. 1