Investigation of Choice for Acute Appendicitis
The investigation of choice is ultrasonography (US) for pediatric patients with suspected acute appendicitis [1]. For nonpregnant adults, contrast-enhanced CT of the abdomen and pelvis is recommended as cross-sectional imaging for suspected appendicitis after initial risk stratification [1].
Medication Selection Algorithm
- Pediatric patients and young adult patients: US is recommended as the initial imaging study of choice for suspected acute appendicitis [1].
- Pregnant patients: MRI is preferred over CT as a first-line cross-sectional imaging study when imaging is needed [1].
- Nonpregnant adults: contrast-enhanced cross-sectional imaging (CT abdomen and pelvis) is recommended in patients needing imaging after initial assessment and risk stratification [1].
Key Evidence Supporting This Recommendation
- US has high diagnostic accuracy as an initial imaging investigation in pediatric and young adult patients with suspected acute appendicitis and reduces or obviates the need for further imaging [1].
- MRI has at least the same sensitivity and specificity as CT for acute appendicitis during pregnancy, with MRI preferred over CT as first-line cross-sectional imaging [1].
Monotherapy vs Combination Therapy (Imaging Strategy)
- A clinico-radiological approach is recommended, using clinical parameters plus US to improve diagnostic sensitivity and specificity and to reduce the need for CT [1].
- Cross-sectional imaging is recommended in patients with suspected appendicitis who have normal investigations but non-resolving right iliac fossa pain, with diagnostic laparoscopy recommended after negative imaging when symptoms persist or progress [1].
Initiation Thresholds or Indications
- Imaging should be performed after initial assessment and risk stratification using clinical scores, with timely and systematic diagnostic imaging used in intermediate-risk patients [1].
- High-risk patients younger than 40 years may be considered for omission of CT preoperatively in selected circumstances based on high clinical score thresholds, with the alternative of diagnostic or therapeutic laparoscopy [1].
Common Pitfalls to Avoid
- Proceeding directly to CT in children without attempting US increases exposure to ionizing radiation without being consistent with guideline-preferred initial imaging [1].
- In pregnancy, using CT instead of MRI when cross-sectional imaging is indicated increases unnecessary radiation exposure, with MRI recommended as preferred first-line cross-sectional imaging [1].
Targets or Goals of Therapy
- The imaging pathway should aim to improve diagnostic accuracy while reducing unwarranted CT use and negative appendectomy rates by using clinical scores plus US as the initial strategy [1].