Appendicitis

Appendicitis
Rennier A. Martinez
  • Accounts for about one-third of childhood admissions for abdominal pain1
  • Peak incidence during adolescence2
  • Diagnosis is difficult especially in younger children
  • Definite diagnosis only in 50% to 70% of cases3
  • Variable diagnostic algorithms depend on physician and institutional factors
  • Appendectomy is still the treatment of choice; however, in select patients nonoperative management can be attempted
RELEVANT ANATOMY
  • Location:
    • Intraperitoneal (95%)
      • Pelvis (30%) and Retrocecal (65%)
    • Retroperitoneal (5%)
  • Size: average 8 cm and 5 to 10 mm wide
  • Blood supply: appendiceal branch of ileocolic artery (lies behind ileum)
  • Base of the appendix arises from confluence of the 3 taeniae coli (useful landmark to find appendix)4
  • McBurney point: most common location of the appendix; one-third of the distance from the anterior superior iliac spine to the umbilicus (Figure 21.1)
ETIOLOGY AND EPIDEMIOLOGY
  • Appendicitis is due to obstruction of the appendiceal lumen leading to vascular congestion, ischemic necrosis, and subsequent infection2,4
    • Commonly due to fecalith (20%)4,5
    • Other causes include lymphoid hyperplasia, carcinoid or other tumors, foreign bodies, and parasites5
  • Pathophysiology:4
    • Obstruction of appendiceal lumen → distention due to accumulating mucus
    • Distention activates T-10 visceral nerve fibers referring to periumbilical region
    • As pressure increases, lymphatic, venous, and, later, arterial flow are compromised; thus, ischemia ensues
    • Localized inflammation activates somatic parietal peritoneum pain fibers causing pain in right lower quadrant (RLQ)
      • Localized abscess or peritonitis occurs late in the process (>24-36 h)
      • Diffuse peritonitis is more common in young children and infants owing to proportionally smaller omentum that is less able to contain advancing inflammatory process (Figure 21.2)
  • Rare in children <2 years of age
  • Children <5 years of age more likely to present with perforation2
Figure 21.1 Location of appendicitis on a female child. McBurney point is indicated as a dot on the center of a dashed line drawn between the anterior spine of ilium and the navel. (Reprinted with permission from Nath JL. Using Medical Terminology. 2nd ed. Philadelphia, PA: Lippincott Williams & Wilkins/Wolters Kluwer Health; 2012.)
Figure 21.2 Common causes of peritonitis. (Reprinted with permission from Timby BK, Smith NE. Introductory Medical-Surgical Nursing. 12th ed. Philadelphia, PA: Wolters Kluwer; 2018.)
CLINICAL PRESENTATION
  • Appendicitis can affect any age group; however, it is extremely rare in neonates and infants.
  • This rarity as well as inability of young children to voice complaints leads often to delay in diagnosis.4,5
Classic presentation: a child with periumbilical pain that over past 12 hours has migrated to RLQ with associated nausea, anorexia, low-grade fever, and leukocytosis.
  • This presentation however is not very common especially in younger children.
  • Pain in the RLQ is the most common symptom.
  • Midabdominal pain migrating to RLQ, and fever increases probability of appendicitis.6
  • Fever, if not present, decreases probability of appendicitis by two-thirds.6
  • Anatomic variability of appendix (ie, retrocecal, pelvic) is common and can alter presentation.
  • Children often lie in bed with minimal movement.
    • A squirming, screaming child rarely has appendicitis.4
      • Exception is the retrocecal appendicitis inflaming the ureter and causing renal colic-type symptoms.
  • Older children will often limp or flex trunk.
  • Referred testicular pain or urinary frequency is often seen in the cases of pelvic appendicitis because of inflammation of the ureter.4
  • Anorexia is another classic presenting symptom. Emesis is mild, and diarrhea may be due to ileocecal inflammation.
    • Severe GI symptoms before onset of pain usually indicate another diagnosis other than appendicitis.5
  • Low-grade fever with temperature <38.6°C is the norm in nonperforated appendicitis.
  • Higher temperature suggests severe inflammation or perforation.
Differential Diagnosis
  • Acute appendicitis can mimic any intra-abdominal process.
  • Have to keep in mind other inflammatory, infectious, vascular, congenital, and genitourinary conditions including the following:
    • Gastroenteritis, Crohn disease, mesenteric adenitis (ie, Campylobacter, viruses), pancreatitis, peptic ulcer, cholelithaisis, cholecystitis, Meckel diverticulitis, constipation, intussusception, ovarian torsion, ovarian cysts, pelvic inflammatory disease, renal stones, pyelonephritis, cystitis, etc.5
      • Systemic disorders that may present with acute abdominal pain include porphyria, sickle cell disease, diabetic ketoacidosis, measles, and parasitic infections.
DIAGNOSIS
Physical Examination
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May 5, 2019 | Posted by in PEDIATRICS | Comments Off on Appendicitis

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