What is the most appropriate next step for a 28-year-old female with right lower quadrant pain, suprapubic and lower quadrant tenderness, leukocytosis (White Blood Cell count 12.5-14), and an inconclusive ultrasound?

CT Abdomen and Pelvis with IV Contrast is the Most Appropriate Next Step

For a 28-year-old female with right lower quadrant pain, suprapubic tenderness, mild leukocytosis (WBC 12.5-14), and an inconclusive ultrasound, CT abdomen and pelvis with IV contrast is the definitive next imaging study, achieving 95% sensitivity and 94% specificity for appendicitis while identifying alternative diagnoses in 23-45% of cases. 1

Why CT is the Correct Choice After Inconclusive Ultrasound

• The American College of Radiology explicitly recommends CT abdomen and pelvis with IV contrast when ultrasound is nondiagnostic or equivocal, as it provides definitive diagnosis and guides surgical decision-making 1

• CT identifies alternative diagnoses that can mimic appendicitis in this demographic, including ovarian pathology, pelvic inflammatory disease, ectopic pregnancy complications, right-sided colonic diverticulitis, and urolithiasis 1, 2

• The mild leukocytosis (12.5-14) combined with 12 hours of pain and inconclusive ultrasound creates diagnostic uncertainty that requires definitive imaging before any surgical intervention 1

Why the Other Options Are Incorrect

B) Transvaginal Ultrasound - Not Appropriate at This Stage

• Transvaginal ultrasound should be considered as initial imaging when there is specific clinical concern for acute gynecologic pathology, not after an already inconclusive transabdominal ultrasound 1

• Adding transvaginal ultrasound after an inconclusive transabdominal study creates diagnostic delay without avoiding the need for CT, as equivocal ultrasound results require CT anyway 2

• The clinical presentation (suprapubic and RLQ tenderness with leukocytosis) suggests intra-abdominal pathology requiring comprehensive evaluation, not isolated gynecologic assessment 1

C) Diagnostic Laparoscopy - Premature Without Imaging Confirmation

• Diagnostic laparoscopy is premature without definitive imaging confirmation, as CT must be obtained first to guide surgical decision-making and avoid unnecessary operative intervention 1

• Proceeding directly to surgery risks both a negative laparoscopy and missing the actual pathology, which could be medical rather than surgical 1

• The absence of rebound tenderness suggests the patient is not peritonitic, making immediate surgery without imaging confirmation inappropriate 1

D) Open Appendectomy - Contraindicated Without Diagnosis

• The American College of Radiology recommends against open appendectomy without imaging confirmation, as it risks both a negative appendectomy and missing the actual pathology 1

• Historical negative appendectomy rates of 14.7% have been reduced to 1.7-7.7% with CT imaging, demonstrating the critical role of imaging before surgery 1

• Open appendectomy is particularly inappropriate given the inconclusive ultrasound—the diagnosis is not established 1

Clinical Algorithm for This Scenario

Step 1: Obtain CT abdomen and pelvis with IV contrast immediately 1

Step 2: If CT confirms appendicitis → proceed to appendectomy (laparoscopic preferred) 1

Step 3: If CT identifies alternative diagnosis → treat accordingly (gynecologic pathology, diverticulitis, etc.) 1, 2

Step 4: If CT is negative → consider observation with serial examinations or outpatient follow-up depending on clinical stability 3

Critical Pitfalls to Avoid

• Do not delay CT imaging in favor of serial examinations or additional ultrasound modalities, as this risks progression to perforation if appendicitis is present 1

• Do not assume gynecologic pathology requires transvaginal ultrasound first—CT will identify both gynecologic and gastrointestinal pathology simultaneously 1, 2

• Do not proceed to surgery without imaging confirmation in a hemodynamically stable patient with atypical examination findings (no rebound tenderness) 1

Radiation Considerations in Young Females

• While radiation exposure is a valid concern in a 28-year-old female, the diagnostic uncertainty after 12 hours of pain with inconclusive ultrasound outweighs radiation risk 1

• Abdominal CT exposes patients to approximately 10 mSv of radiation, but delaying diagnosis risks perforation with significantly higher morbidity 1

• Low-dose CT protocols can reduce radiation exposure to approximately 22% of standard-dose protocols without compromising diagnostic accuracy if available at your institution 1