This document discusses the classification, etiology, signs and symptoms, laboratory studies, ultrasound findings, and CT imaging findings of acute appendicitis. It defines uncomplicated appendicitis as having no evidence of complications like perforation or abscess, while complicated appendicitis is associated with such complications. The most common causes are lymphoid hyperplasia in children and appendiceal fecaliths in adults, which can obstruct the appendix lumen. Key signs include migrating abdominal pain localized to the right lower quadrant, along with tenderness at McBurney's point and guarding. Laboratory tests may show a leukocytosis with elevated CRP. Ultrasound and CT imaging can detect a distended appendix

1. Classification of acute

5. Appendicitis: acute inflammation of the vermiform
appendix
• Appendicitis: acute inflammation of
the vermiform appendix
• Uncomplicated appendicitis: appendicitis
with no evidence of an appendiceal
fecalith, an appendiceal tumor, or
complications, such as
perforation, gangrene, abscess, or mass
• Complicated appendicitis: appendicitis
associated with
perforation, gangrene, abscess, an
inflammatory mass, an appendiceal
fecalith, or an appendiceal tumor

6. Etiology
• Caused by obstruction of the appendiceal
lumen due to:
• Lymphoid tissue hyperplasia (60% of cases): most
common cause in children and young adults
• Appendiceal fecalith (concretion of feces that
develops in the appendix that can obstruct the
appendiceal lumen) and fecal stasis (35% of
cases): most common cause in adults
• Neoplasm (uncommon): more likely in patients >
50 years of age
• Parasitic infestation (uncommon):
e.g., Enterobius vermicularis, Ascaris
lumbricoides, and species of
the Taenia and Schistosoma genera

7. Signs of appendicitis
• Migrating abdominal pain: most common and specific
symptom
• McBurney point tenderness (RLQ tenderness)
• Tenderness at the junction of the lateral third and medial two-
thirds of a line drawn from the right anterior superior iliac
spine to the umbilicus
• This point corresponds to the location of the base of
the appendix.
• RLQ guarding and/or rigidity
• Rebound tenderness (Blumberg sign), especially in the RLQ
• Rovsing sign: RLQ pain elicited on deep palpation of the LLQ

14. Laboratory studies
CBC: mild leukocytosis with left
shift
• CRP: elevated (> 10 mg/L) [10]
• BMP:
↑ creatinine, electrolyte abnorm
alities may be present in patients
with
severe vomiting and diarrhea
• Urinalysis: typically normal in
appendicitis; possible findings of
mild pyuria and/or hematuria
• Urine/serum β-hCG test: perform in
all women of reproductive age to rule
out pregnancy (including ectopic
pregnancy)

15. Abdominal ultrasound
• Supportive findings [10][31]
• Distended appendix (diameter > 6
mm)
• Noncompressible, aperistaltic,
distended appendix
• Target sign: concentric rings of
hypo- and hyperechogenicity in the
axial/transverse section of
the appendix

16. CT abdomen with IV contrast
• CT abdomen is the most accurate
initial imaging modality for
appendicitis. [10][12][28]
• Supportive findings [28]
• Distended appendix (diameter > 6
mm)
• Edematous appendix with
periappendiceal fat stranding
• Possible appendiceal fecalith:
focal hyperdensity within the
appendiceal lumen
• Evidence of complications