Appendicitis

Snapshot

• A 46-year-old man presents to the emergency department with nausea, vomiting, constipation for the past 2 days. He also complains of abdominal pain that initially started at the periumbilical area then traveled to the right lower quadrant. He is tachycardic, febrile, and mildly hypertensive on examination. A physical examination demonstrates a diffusely tender abdominal with rebound, especially at the right lower quadrant. 

Introduction

• Clinical definition
  • medical condition characterized by the inflammation of the appendix, a vestigial structure located at the base of the cecum 
  • it is one of the most common causes of the acute abdomen
• Epidemiology
  • demographics
    • most commonly occurs during the 2^nd and 3^rd decades of life
    • incidence of 233/100,000 and highest in the 10-19-year-old age group
• Pathogenesis
  • the natural process involves initial inflammation of the appendiceal wall followed by local ischemia, perforation, and leading to abscess development or generalized peritonitis
  • obstruction of the appendix is the proposed primary cause
    • fecaliths (hard fecal masses)
    • calculi
    • lymphoid hyperplasia 
      • more common in the young
    • infectious process
    • benign/malignant tumors
  • obstruction of the appendix leads to an increase in luminal and intramural pressure leading to the thrombosis and occlusion of the small vessels in the appendiceal wall and stasis of lymphatic flow
    • bacterial overgrowth occurs with predominately aerobic organisms
  • the engorged appendix stimulates the visceral afferent nerve fibers at the T8-T10 level leading to the initial central/periumbilical abdominal pain
• the latter localized pain at the RLQ occurs due to inflammation of the adjacent parietal peritoneum

Presentation

• Symptoms 
  • abdominal pain  
    • initial periumbilical pain with migration to the RLQ
  • anorexia
  • nausea
  • vomiting
  • diarrhea
  • indigestion
• Physical exam 
  • fever
  • McBurney point tenderness 
  • Rovsing sign 
    • pain in the RLQ with palpation of the left lower quadrant (LLQ)
  • Psoas sign 
    • associated with retrocecal appendix
    • RLQ pain with passive right hip extension
  • Obturator sign 
• RLQ pain with right hip flexion followed by internal rotation

Imaging

• Abdominopelvic computed tomography (CT) with IV contrast
  • preferred test in patients suspected with appendicitis as it has the highest diagnostic accuracy when compared to other imaging modalities
  • positive findings include wall thickening (> 2 mm), periappendiceal fat stranding, appendiceal wall enhancement, appendicolith, and enlarged appendiceal double-wall thickness (> 6 mm) 
• Ultrasound 
  • preferred test in children and pregnant women due to its lack of ionizing radiation and IV contrast and can be performed at bedside
  • though results may be variable, patient- and operator-dependent
  • positive findings include focal pain over appendix with compression, noncompressible appendix with enlarged double-wall thickness (> 6 mm), increased echogenicity of inflamed periappendiceal fat, and fluid in the right lower quadrant  
• Magnetic resonance imaging (MRI)
• indicated for pregnant women or older children who can tolerate the exam

Studies

• Serum pregnancy test 
  • should be performed in all women of childbearing age prior to imaging that exposes a potential fetus to radiation and to rule out other causes of acute abdomen
• White blood cell count with differential
• often will demonstrate leukocytosis with left shift

Differential

• Ectopic pregnancy 
  • differentiating factors
    • will have positive urine pregnancy test and perhaps positive pelvic ultrasound findings
• Ovarian/fallopian tube torsion
  • differentiating factors
    • will appear on CT imaging
• Renal colic 
  • differentiating factors
    • will appear on CT of the abdomen and will generally present with hematuria
• Psoas abscess
  • pain to palpation
  • pain with stretching of the psoas muscle
• diagnose with CT 

Treatment

• Non-perforated appendicitis
  • appendectomy (laparoscopic or open) 
    • should be performed within 12 hours of diagnosis
    • laparoscopic approach is more common and popular
  • antibiotics
    • though there is growing popularity with antibiotic-alone therapy
• Perforated appendicitis with hemodynamic instability, sepsis, free perforation, or peritonitis
  • emergency appendectomy
  • irrigation and drainage of peritoneal cavity
  • bowel resection if needed
• Stable perforated appendicitis
  • initial nonoperative management
    • IV antibiotics
    • percutaneous drainage of abscess if present
• rescue appendectomy for patients who do not respond to antibiotic

Prognosis, Prevention, and Complications

• Perforation
  • leads to peritonitis
• Periappendiceal abscess
  • most commonly due to B. fragilis
• Pylephlebitis
  • inflammation of the portal vein
  • ↑ risk of thrombosis
• Septicemia
• Subphrenic abscess
  • fixes diaphragm on the right
  • tenderness over 7/8th ribs
• Death