Should I proceed with an ultrasound (USG) as the next step for a patient with a complaint of abdominal pain but no tenderness on examination?

Ultrasound is the Appropriate Next Step for Abdominal Pain with No Tenderness on Examination

For a patient with complaints of abdominal pain but no tenderness on examination, ultrasound (USG) should be performed as the next diagnostic step. 1

Rationale for Ultrasound as First-Line Imaging

Ultrasound offers several advantages as the initial imaging modality for evaluating abdominal pain without clinical tenderness:

• The World Journal of Emergency Surgery guidelines recommend a step-up approach for diagnosis of intra-abdominal conditions, starting with clinical and laboratory examination, followed by imaging tailored to available resources 2
• Ultrasound is recommended as the first-line imaging modality for patients with diffuse abdominal pain after clinical assessment and basic laboratory tests 1
• It provides several practical advantages:
  • No radiation exposure
  • Cost-effective resource utilization
  • Readily available in most settings
  • Can be performed at bedside
  • Safe for all patient populations 1, 3

Clinical Approach Algorithm

1. Initial Assessment

   • Complete clinical evaluation (already performed, noting absence of tenderness)
   • Basic laboratory tests (complete blood count, electrolytes, liver enzymes, inflammatory markers)
   • Pregnancy test for women of reproductive age

2. Proceed with Ultrasound

   • Focus on areas corresponding to the patient's pain location
   • Evaluate for common causes of abdominal pain:
     • Gallbladder pathology (cholecystitis, cholelithiasis)
     • Appendicitis
     • Urinary tract conditions (stones, hydronephrosis)
     • Free fluid
     • Bowel abnormalities
     • Gynecological pathology in female patients

3. Follow-up Based on Ultrasound Results

   • If ultrasound is diagnostic: proceed with appropriate management
   • If ultrasound is equivocal or negative but clinical suspicion remains high: proceed to CT scan 2, 1

Evidence Supporting This Approach

The 2017 World Journal of Emergency Surgery guidelines emphasize that diagnosis of intra-abdominal conditions is primarily clinical, with imaging used to confirm suspicions 2. When imaging is needed, a step-up approach is recommended, beginning with ultrasound and progressing to CT when necessary.

For patients with abdominal pain but normal physical examination, ultrasound has been shown to be highly effective as an initial diagnostic tool. It can identify or exclude many common causes of abdominal pain with high sensitivity and specificity 1, 3.

Important Considerations and Pitfalls

• Operator Dependence: The quality and diagnostic accuracy of ultrasound depend heavily on the operator's experience 1
• Body Habitus Limitations: Ultrasound may be less effective in obese patients 1
• Discordance Between Symptoms and Examination: The absence of tenderness despite reported pain requires careful evaluation, as some serious conditions may present with minimal examination findings 2
• Avoid Common Pitfalls:
  • Don't dismiss pain as functional without adequate workup
  • Don't delay imaging in patients with significant pain despite normal examination
  • Don't rely solely on laboratory tests without appropriate imaging 1

If ultrasound is inconclusive or negative but clinical suspicion remains high, CT scan should be considered as the next step, as it provides higher sensitivity for certain conditions and can identify alternative diagnoses 2, 1.