How should I assess a patient with a suspected abdominal wall hernia in primary care?

Assessment of Suspected Abdominal Wall Hernia in Primary Care

Begin with a focused history and physical examination looking specifically for a palpable bulge that increases with coughing or Valsalva maneuver, assess for signs of complications (irreducibility, tenderness, erythema, systemic symptoms), and examine both sides of the groin to avoid missing contralateral or femoral hernias. 1, 2, 3

Initial Clinical Assessment

Key History Elements

• Symptom characterization: Ask about groin pain (which can be severe), burning, gurgling, or aching sensation in the groin, and heavy or dragging sensation that worsens toward end of day and after prolonged activity 3
• Red flag symptoms requiring urgent evaluation: 1, 2
  • Irreducibility of the bulge
  • Overlying skin changes (redness, warmth, swelling)
  • Fever, tachycardia, or systemic symptoms
  • Abdominal wall rigidity
  • Symptoms lasting >8 hours (significantly increases morbidity)
• Risk factors: Previous abdominal or groin surgeries, obesity, chronic cough, constipation, heavy lifting 2, 3

Physical Examination Technique

• Bilateral groin examination is mandatory: Examine both groins even if patient reports unilateral symptoms, as contralateral hernias occur in 11-50% of cases and femoral hernias have higher strangulation risk 2, 3
• Palpation technique: Feel for a bulge or impulse while patient coughs or performs Valsalva maneuver; the bulge typically disappears when patient lies supine 3, 4
• Hernia defect assessment: Palpate for interruption in the abdominal wall fascia 5
• Assess for complications: Check for tenderness, erythema, inability to reduce the hernia, and signs of peritonitis 1, 2

Distinguishing Hernia from Other Conditions

• Abdominal wall hernia characteristics: Swelling increases on standing and with Valsalva, often reducible, hernia defect is palpable 5
• If no fascial defect is palpable and hypoesthesia is present: Consider neurological causes such as abdominal wall paresis from thoracic disc herniation 5

When Imaging is Indicated

Clinical Scenarios Requiring Imaging

Most hernias are diagnosed clinically and do not require imaging 3. However, imaging is indicated when:

• Suspected complications (incarceration, strangulation, bowel obstruction) 1, 2
• Uncertain diagnosis on physical examination 3
• Obese patients where physical examination is unreliable 2
• Athletes without palpable impulse or bulge but high clinical suspicion 3
• Recurrent hernias or post-surgical complications 3

Imaging Modality Selection

For suspected uncomplicated hernia with uncertain diagnosis:

• Ultrasound is the first-line imaging modality for occult hernias, particularly useful in athletes and when diagnosis is uncertain 3
• MRI is reserved for occult hernias when ultrasound is negative but clinical suspicion remains high 2, 3

For suspected complicated hernia (incarceration/strangulation):

• Contrast-enhanced CT of abdomen and pelvis with IV contrast is the imaging modality of choice 1, 6, 7
• CT provides superior sensitivity and specificity for identifying hernia location, contents, and complications 7
• Key CT findings suggesting strangulation: 1, 7, 2
  • Bowel wall thickening with target enhancement
  • Absence of bowel wall contrast enhancement (indicates strangulation)
  • Reduced wall enhancement (56% sensitivity, 94% specificity for strangulation)
  • Pneumatosis intestinalis or portal venous gas (indicates bowel necrosis)

Laboratory Testing

Routine laboratory tests are not necessary for uncomplicated hernias. 1

For suspected strangulation, obtain: 1, 2

• Complete blood count (elevated WBC is moderately predictive)
• Arterial lactate (≥2.0 mmol/L predicts non-viable bowel)
• Serum creatinine
• C-reactive protein
• Creatine phosphokinase (CPK)
• D-dimer levels
• Fibrinogen (can predict morbidity in incarcerated hernias)

Urgent Referral Criteria

Immediate surgical referral (same-day) is required for: 1, 2

• Signs of strangulation or incarceration (irreducible hernia with tenderness, erythema, systemic symptoms)
• Peritonitis or abdominal wall rigidity
• Hemodynamic instability
• Symptoms >8 hours duration with concerning features

Urgent surgical referral (within 1-2 weeks) for: 2, 3

• All symptomatic hernias
• Asymptomatic hernias in appropriate surgical candidates (most hernias are repaired even if asymptomatic due to complication risk) 8

Common Pitfalls to Avoid

• Failing to examine both groins bilaterally: Missing contralateral or femoral hernias, which have higher strangulation risk 2
• Delaying evaluation when signs of strangulation are present: Delayed treatment beyond 24 hours is associated with significantly higher mortality 2
• Ordering imaging for straightforward clinical hernias: History and physical examination are usually sufficient; imaging is rarely warranted in uncomplicated cases 3
• Assuming normal labs exclude strangulation: Elevated lactate is the only laboratory parameter significantly associated with non-viable bowel, but normal values cannot exclude ischemia 1