Acute Abdominal Pain PEDS

Differential Diagnosis 

• Gastroenteritis (Most common Medical cause)  

• Appendicitis (Most common Surgical cause). 

• Peptic ulcer

• Intestinal obstruction

• Meckel’s diverticulum

• IBD

• Mesenteric Lymphadenitis 

• Lactose intolerance

• Splenic rupture

• UTI, Urinary calculi

• PID, Ectopic pregnancy, Dysmenorhhea

• Ovarian/testicular torsion, Endometriosis

• Sickle cell anemia, Henoch-Schonlein purpura, HUS

• Salicylates, lead poisoning, erythromycin, venoms

• DKA, Hypoglycemia, porphyria, acute adrenal insufficiency

• Pneumonia, diaphragmatic, Pleurisy

Epidemiology/Etiology

History

Physical Exam

Labs

• CBC 

• CRP

• Urine/Serum Pregnancy test

• UA if considering UTI

Diagnostic Criteria for Appendicitis in US

1. Appendiceal diameter >6-7mm

2. Non compressible appendix

3. Fat stranding (hyperechoic signals associated with peri appendiceal inflammation)

4. Peritoneal fluid surrounding appendix

US Normal Appendix vs. Appendicitis: https://www.youtube.com/watch?v=-pElyV8KUjU

Diagnostic Criteria for Appendicitis on CT

• Appendiceal diameter (>6 mm with surrounding inflammation or >8 mm without such changes)

• Wall thickening >2 mm Calcified appendicolith

• Signs of peri appendiceal inflammation (eg, fat stranding, clouding of the adjacent mesentery)

Abdominal CT showing Appendicitis: https://www.youtube.com/watch?v=zRVolnDDuY0

Ultrasound Pros/Cons

Pros: Decreased cost, in comparison to other imaging modalities

• Lack of ionization radiation

• Decreased time to diagnosis

• #1 image of choice in all pregnant patients, especially if you need to determine ovarian pathology or tubo-ovarian abscesses

Cons: Increased pain from transducer pressure

• Poor visualization of the appendix either due to lack of operator experience, obesity, superimposed bowel gas, or atypically located appendix

• Not as effective at diagnosing appendicitis, with a sensitivity for diagnosis of 60% to 70%, with specificities of 94% to 98%

CT Scan Pros/Cons

Pros:

• CT of the abdomen and pelvis is considered the test of choice for definitive assessment of possible appendicitis in nonpregnant patients.

• Sensitivity of 94% to 100% and specificity of 91% to 99%.

• PPV of 95% to 97%.

• Very accurate and consistent in diagnosing of appendicitis in children and decreased negative appendectomy rate

• Readily available in most hospitals and not operator dependent 

• Easily interpreted by most radiologists and surgeons and has a greater likelihood of finding an alternative diagnosis as opposed to US

Cons:

• An abdominal CT carries an excess risk of fatal cancer of 1 in 2000, a value that is even greater in children.

• Children and fetuses having the greatest risk of adverse outcomes of radiation due to their smaller body habitus, more rapidly developing cells, and increased incubation time for genetic mutations to manifest

• Ionization Exposure

Appendicitis Risk Prediction Models

American College of Radiology

ACR Appropriateness Criteria

Suspected Appendicitis–Child