CT Abdomen and Pelvis with IV Contrast
For this 45-year-old man with periumbilical pain migrating to right lower quadrant tenderness, the most appropriate next step is CT abdomen and pelvis with intravenous contrast (no oral contrast needed). 1, 2
Rationale for Imaging Over Clinical Observation
Clinical assessment alone misdiagnoses appendicitis in 34-68% of cases, leading to negative appendectomy rates as high as 25% when imaging is omitted. 1
The classic presentation of appendicitis (periumbilical pain migrating to RLQ) is only present in approximately 50% of cases, and fever is absent in about 50% of appendicitis patients—making the absence of fever unreliable for excluding the diagnosis. 1, 3
His obesity (BMI 37) further limits the accuracy of physical examination and makes ultrasound technically challenging due to body habitus. 1
Right lower quadrant tenderness with a history of migrating pain warrants definitive imaging rather than observation, as this presentation carries intermediate-to-high pretest probability for appendicitis despite the atypical features (no fever, preserved appetite). 1, 2
Diagnostic Performance of CT
CT with IV contrast demonstrates 85.7-100% sensitivity and 94.8-100% specificity for acute appendicitis, making it the gold standard for diagnosis. 1, 2
Critically, CT identifies alternative diagnoses in 23-45% of patients presenting with right lower quadrant pain and suspected appendicitis, fundamentally changing management in nearly half of cases. 1, 2
Common alternative diagnoses include right colonic diverticulitis (8%), ureteral stones, bowel obstruction (3%), gynecologic pathology (21.6% of alternatives), and gastrointestinal conditions (46% of alternatives). 1
Why Not Observation or Discharge?
Discharging this patient based solely on absence of fever and mild symptoms risks missing early appendicitis or other serious pathology that requires intervention. 1
The combination of migrating pain pattern and localized RLQ tenderness creates sufficient clinical concern that observation without imaging is inappropriate—this is not a low-risk presentation. 1
Even a 24-hour observation period with serial exams is inferior to immediate CT, which provides a definitive diagnosis and avoids the risk of perforation during the observation window. 1
Technical Imaging Protocol
Order CT abdomen and pelvis with IV contrast only—oral contrast is unnecessary and delays diagnosis without improving accuracy (sensitivity 90-100%, specificity 94.8-100% with IV contrast alone). 1, 2
The study should evaluate for appendiceal diameter >8.2 mm, periappendiceal fat stranding, wall enhancement, and absence of intraluminal gas. 1
Management Based on CT Results
If appendicitis is confirmed (appendix >8.2 mm with periappendiceal inflammation): immediate surgical consultation for appendectomy. 1
If perforated appendicitis with abscess: percutaneous drainage followed by interval appendectomy. 1
If CT is negative but symptoms persist: mandatory 24-hour follow-up with instructions to return immediately for worsening pain, fever, vomiting, or inability to tolerate oral intake. 1
Critical Pitfalls to Avoid
Do not rely on absence of fever to exclude appendicitis—it is absent in half of cases. 1, 3
Do not delay imaging for oral contrast administration—IV contrast alone is sufficient and faster. 1, 2
Do not assume appendicitis is the only diagnosis—approximately 50% of RLQ pain patients have alternative pathology requiring different management. 1, 2
Do not discharge without imaging in a patient with migrating pain and localized tenderness—this presentation warrants definitive evaluation. 1