40 yo F presents to the ED w/ 12 hours of GI symptoms. She had nausea and vomiting, then developed right lower quadrant abomdinal pain. Labs were significant for an elevated WBC count. A CT A/P was obtained. What's the diagnosis? (scroll down for answer) 

Answer: Acute Appendicitis

• due to luminal obstruction (most commonly by fecalith); increase in intraluminal pressure leads to vascular insufficiency--> bacterial proliferation and inflammation
• other causes: obstruction by lymphatic tissue, tumor, parastic infection
• early: poorly localized/periumbilical discomfort (due to viserval innervation)
• classic finding is migration of pain to RLQ (at McBurney's point) due to somatic innervation of peritoneum
• Mc Burney's point-- 1/3 distance from ASIS to umbilicus
• up to 50% can have atypical presentation: r pelvic/flank pain (retrocecal appendix), L sided pain (due to malrotation), RUQ pain (due to gravid uterus in pregnancy) 
• lab findings: elevated wbc and/or CRP, sterile pyuria
• CT findings- appendix > 6mm in diameter, wall thinkening > 2mm and fat stranding

• treatment: surgical consult and appendectomy (standard of care per American College of Surgeons)
• Pre-op antibiotics to cover aerobic and anaerobic gram negative organisms
• Antibiotics for non-operative management ?
• several RTC studies have addressed- consider in select patients (those refusing surgery, high risk surgical candidates)
• surgery still considered standard of care
• the Eastern Associated for the Surgery of Trauma conducted a systematic review and meta-analysis of non-operative management as an approach to acute appendicits and were unable to make a recommendation for or against the use of an antibiotics first approach as the primary treatment of acute uncomplicated appendicitis

References:

DeKoning E. Acute Appendicitis. In: Tintinalli JE, Ma O, Yealy DM, Meckler GD, Stapczynski J, Cline DM, Thomas SH. eds. Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9e New York, NY: McGraw-Hill

Rushing A, Bugaev N, Jones C, et al. Management of acute appendicitis in adults: A practice management guideline from the Eastern Association for the Surgery of Trauma. J Trauma Acute Care Surgery. 2019;87(1):214-224