What is the initial step to diagnose a suspected hernia?

Initial Diagnostic Approach for Suspected Hernia

The initial step to diagnose a suspected hernia is a focused physical examination of the suspected hernia site with inspection and palpation, supplemented by specific maneuvers based on location, with imaging reserved for unclear cases or specific hernia types. 1

Physical Examination Technique

For groin hernias, examine the patient in both standing and supine positions while performing a Valsalva maneuver to reveal reducible hernias. 1 Palpate for a bulge or impulse while the patient coughs or strains. 2 Look for:

• Visible abdominal bulge that may disappear when prone 2
• Groin pain (often burning, gurgling, or aching) 2
• Heavy or dragging sensation that worsens with prolonged activity 2

For suspected diaphragmatic hernias, begin with chest X-ray (both anteroposterior and lateral views) as the first diagnostic study in patients with respiratory symptoms. 3 However, be aware that normal chest radiographs occur in 11-62% of diaphragmatic injuries or uncomplicated hernias, so a negative X-ray does not exclude the diagnosis. 3, 1

For anorectal hernias, digital rectal examination may be necessary, but should be performed after abdominal X-ray if a foreign body is suspected. 1

When to Proceed to Imaging

First-Line Imaging by Hernia Type

For diaphragmatic hernias in stable trauma patients, contrast-enhanced CT scan of chest and abdomen is the gold standard when clinical suspicion persists despite chest X-ray findings. 3 CT has sensitivity of 14-82% and specificity of 87%, and can identify diaphragmatic discontinuity, the "dangling diaphragm" sign, "collar sign," and herniated abdominal contents. 3

For abdominal wall and inguinal hernias, ultrasonography is the recommended first-line imaging, especially for women and unclear diagnoses. 1 Ultrasonography is particularly indicated when:

• The diagnosis is uncertain on physical examination 2
• Evaluating athletes without palpable impulse or bulge 2
• Assessing recurrent hernias or suspected hydrocele 2
• Investigating surgical complications 2

For stable trauma patients with lower chest penetrating wounds, diagnostic laparoscopy is recommended when diaphragmatic hernia is suspected but imaging is nondiagnostic. 3

Advanced Imaging Considerations

MRI can be used as an alternative to ultrasonography for diagnosing hernias in athletes without palpable findings on examination. 2 In pregnant patients with suspected non-traumatic diaphragmatic hernia, ultrasonography is suggested first, followed by MRI if needed. 3

CT imaging is valuable for detecting unsuspected hernias and distinguishing hernias from abdominal wall masses such as tumors, hematomas, or abscesses. 4, 5 CT can demonstrate the anatomic location, contents, and complications including incarceration, bowel obstruction, volvulus, and strangulation. 5

Laboratory Testing

Routine laboratory tests are not recommended for uncomplicated hernias. 1 However, in cases of suspected strangulation or incarceration, obtain complete blood count, serum lactate, D-dimer, CPK, and inflammatory markers. 1

Critical Pitfalls to Avoid

• Do not rely solely on chest X-ray for diaphragmatic hernias—false negatives occur in up to 62% of cases. 3, 1
• Do not assume a negative CT excludes internal hernias in post-bariatric surgery patients. 1
• Do not skip imaging in obese patients or those with prior surgery, as physical examination can be unreliable and cross-sectional imaging may be necessary. 4
• In stable trauma patients with persistent clinical suspicion, always proceed to CT scan even if chest X-ray appears normal. 3