Step 1: Interpret the clinical picture.
Right iliac fossa pain of 48 hours' duration with a diagnostic ultrasound points to acute appendicitis. The classic USG signs are a non-compressible, blind-ending tubular structure >6 mm in diameter, target/bull's-eye appearance, peri-appendiceal fluid and increased colour-Doppler flow in the wall.
Step 2: Decide on the next step.
When ultrasound confirms uncomplicated acute appendicitis, the definitive treatment is surgery (appendicectomy), ideally laparoscopic. A confident sonographic diagnosis within 48 hours does not warrant delaying definitive treatment.
Step 3: Eliminate the other options.
• CECT is reserved for equivocal cases or where the appendix is not visualised on USG; here the USG is already diagnostic, so further imaging is unnecessary.
• USG-guided drainage is appropriate only for a well-formed appendicular abscess (a later complication), not for acute appendicitis without a drainable collection.
• Antibiotics alone is not the standard definitive answer in an exam setting once appendicitis is confirmed and the patient is fit for surgery.
Step 4: Conclusion.
USG-confirmed acute appendicitis presenting acutely → proceed to surgery. Key fact: an inflamed, non-compressible blind-ending tubule >6 mm with hyperaemic wall on Doppler is diagnostic of acute appendicitis and mandates appendicectomy.