Appendicitis 

epidemiology

• 6% of population, higher incidence among men
• 80% between 5-35 years of age
• diagnosis may be difficult (atypical presentation in very young and very old)
• patients may not seek medical attention early

pathogenesis

• luminal obstruction of appendix
• children/young adult: hyperplasia of lymphoid follicles, initiated by infection
• adult: fibrosis/stricture, fecolith, neoplasm
• all ages: parasites, foreign body, neoplasm (rare)
• natural history: obstruction ––> bacterial overgrowth ––> inflammation/swelling
  • increased pressure ––> localized ischemia ––> gangrene/perforation
  • contained abscess or peritonitis

clinical presentation

• only reliable feature is progression of signs and symptoms
• low grade fever, anorexia
• nausea and vomiting after pain starts
• early (localized inflammation): constant dull, poorly localized abdominal pain, periumbilical (due to visceral innervation and embryological origins)
• late: well localized pain where the appendix irritates overlying parietal peritoneum
• inferior (to cecum) appendix
  • pain at McBurney’s point: pain 1/3 of the distance along a line drawn between the anterior iliac spine and umbilicus, Rovsing’s sign: pressure in the LLQ elicits pain in the RLQ, rectal exam may elicit pain as well
• retrocecal appendix
  • positive psoas sign: pain on extensin of the right hip
• pelvic appendix
  • positive obturator sign: pain with passive rotation of the flexed right hip when in the supine position, +/– urinary frequency, dysuria, diarrhea
• perforation ––> peritonitis ––> rebound tenderness
• pregnancy: appendix may be superior at the level of the fundus, pain may be in the RUQ

diagnosis

• laboratory (not diagnostic, help to rule out other diagnoses i.e. UTI)
• mild leukocytosis (although many have normal WBC counts) with left shift
• higher leukocyte count with perforation
• radiology (not very helpful in establishing a diagnosis)
• x-rays: usually nonspecific; free air if perforated, look for calculus
• CT scan (standard or appendiceal CT with rectal contrast): thick wall, appendicolith
• consider ultrasound or laparoscopy in female

differential diagnosis

• Gynaecological:
  • ovarian cyst rupture
  • ectopic pregnancy
  • pelvic inflammatory disease
• Renal:
  • ureteric stones
  • urinary tract infection
  • pyelonephritis
• Gastrointestinal:
  • inflammatory bowel disease
  • Meckel’s diverticulum (common congenital anomaly of the gastrointestinal tract. It results from incomplete obliteration of the vitelline duct leading to the formation of a true diverticulum of the small intestine)
  • diverticular disease
• Urological:
  • testicular torsion
  • epididymo-orchitis
• Specifically in children, differentials to consider include
  • acute mesenteric adenitis
  • gastroenteritis
  • constipation
  • intussusception
  • urinary tract infection

treatment

• surgical (possible laparoscopy)
• 70-80% rate of true appendicitis is acceptable
• need to be aggressive with young females as perforation may cause infertility due to tubal damage
• hydration, correct electrolyte abnormalities
• perioperative antibiotics: non-perforated ––> cefazolin + metronidazole
• perforated ––> ceftriaxone + metronidazole