Basics
Description
Acute inflammation or infection of the vermiform appendix
Epidemiology
- Most common surgical emergency of childhood
- Affects 5 of 100,000 persons in the United States
- 293,000 admissions in the United States in 2010
- 80,000 pediatric cases per year in United States
- Most commonly seen in ages 5-40 years, with peak age of incidence age 28 years
Pathophysiology
- Acute inflammation of the appendiceal lumen is caused by obstruction (i.e., by a fecalith, calculi, parasites, hyperplastic lymphoid tissue, or tumor).
- Appendix is innervated by somatic afferent nerves of the 10th dermatome overlying the epigastrium and periumbilical areas.
- In the first phase of pain, occlusion causing increasing wall tension results in vague pain poorly referred to this area.
- Increasing wall tension and full-thickness serositis results in inflammation of surrounding tissues, and the second phase of pain is localized to the area in which the appendix is lying.
- In 85% of patients, this is at McBurney point, but pelvic, retrocecal, retroperitoneal, inguinoscrotal, or other orientations will result in variance of location and intensity of this pain.
Diagnosis
Classic signs and symptoms include right lower quadrant pain, anorexia, nausea and vomiting, and fever.
History
- Abdominal pain is most common symptom.
- Pain usually begins in the periumbilical or epigastric regions prior to migrating to the right lower quadrant. Pain is followed by nausea and vomiting with fever.
- Leukocytosis occurs later.
- Timing of pain preceding nausea and vomiting and absence of diarrhea in most cases are distinguishing factors from gastroenteritis.
- Anorexia is present in the majority of cases but may not be a prominent symptom if the appendix is retrocecal or retroperitoneal.
- Perforation of the inflamed appendix may result in temporary relief of pain. These patients can proceed to develop distension, dehydration, diarrhea from perirectal irritation, and dysuria from perivesicular irritation.
- Delayed diagnosis and perforation occur more frequently in young children, presumably because they are less able to articulate their symptoms.
Physical Exam
- Low-grade fever is common unless perforation has already occurred.
- Perforation can result in worsened fever, tachypnea, and tachycardia.
- Pain and tenderness at McBurney point (1/3 the distance from the anterior superior iliac spine [ASIS] in a line from the umbilicus to the ASIS)
- Findings may include abdominal rebound tenderness, guarding, and focal tenderness on rectal exam.
- Other signs:
- Rovsing sign is pain in the right lower quadrant with palpation in the left lower quadrant.
- Psoas sign is pain in the right lower quadrant with passive right hip extension and may be associated with a retrocecal appendix.
- Obturator sign is pain in right lower quadrant with right hip and knee flexion followed by internal rotation and may be associated with a pelvic appendix.
Diagnostic Tests & Interpretation
Lab
- CBC, expect elevated WBC count (10,000-17,000 cells per μL range) with left shift
- Erythrocyte sedimentation rate is usually normal.
- C-reactive protein can be elevated but is nonspecific.
Imaging
Diagnosis can often be made with history, physical exam, and laboratory studies without imaging with a diagnostic accuracy of 80-90% in some studies.
- Abdominal radiograph
- Often normal
- May show fecalith, indistinct psoas margins, cecal wall thickening
- Free air or pneumoperitoneum may indicate a perforation.
- Ultrasound
- Currently considered the initial imaging study of choice for the diagnosis of appendicitis
- Findings include edema, inflammation, or abscess formation.
- Most specific finding is an appendiceal maximum outer diameter (MOD) of ≥7 mm (associated with a sensitivity of 98.7% and a specificity of 95.4% for the diagnosis).
- CT scan
- Has a high diagnostic accuracy for appendicitis and may have a higher sensitivity than ultrasound; however, requires exposure to ionizing radiation and may be avoidable with careful history and physical exam, use of labs, and less invasive imaging
- Findings include fat stranding, abscess or phlegmon, appendicolith when present, and focal cecal thickening.
Differential Diagnosis
- Infection
- Gastroenteritis (e.g., Yersinia, Campylobacter)
- Constipation
- Right lower lobe pneumonia
- Mesenteric adenitis
- Typhlitis
- Urinary tract infection
- Pelvic inflammatory disease, tubo-ovarian abscess, or ectopic pregnancy
- Parasitic infection (Trichuris trichiura, Ascaris lumbricoides)
- Inflammatory
- Inflammatory bowel disease
- Anaphylactic purpura
- Cholecystitis
- Pancreatitis
- Diverticulitis
- Genetic/metabolic
- Diabetes
- Sickle cell disease
- Renal stones
- Hypernatremia
- Crohn disease
- Miscellaneous
- Functional abdominal pain
- Torsion of testes or ovaries
- Ovarian cyst
- Endometriosis
- Small bowel obstruction
Treatment
General Measures
- IV fluids to correct hypovolemia, electrolyte abnormalities
- Broad-spectrum antibiotics
- Pain medications
Surgery/Other Procedures
- Emergency appendectomy
- Laparoscopic technique is now practiced by most surgeons in the United States.
- It shows comparable results to open technique, allows wider exploration, and is associated with faster recovery in adults to daily activity.
- Laparoscopic approaches now include single-port technology that limit the incision to the umbilical location.
- Given the relative risk and delay of care with CT prep, there is some evidence that immediate surgery may be preferential to radiologic investigation.
- Perforated appendicitis
- Can also be treated via a laparoscopic approach and use of suction/irrigation devices to cleanse the abdomen of collections.
- In many patients with perforated appendicitis, nonoperative management with percutaneous abscess drainage and broad-spectrum antibiotics followed by interval appendectomy may be preferable.
Ongoing Care
Prognosis
- Recovery is rapid.
- Prognosis is excellent.
- Overall current survival rate in United States is 98%.
- It is estimated that 35,000 people die yearly from appendicitis worldwide.
Complications
- Rate of wound complication post laparoscopic appendectomy is 3.1%.
- Rate of abscess formation post appendectomy is 0-4% for nonperforated appendicitis and 14-20% for perforated appendicitis.
- Perforated appendicitis may result in greater risk of postoperative ileus and small bowel obstruction or fertility issues longer term.
Additional Reading
- Bansal S, Banever GT, Kerrer FM, et al. Appendicitis in children less than 5 years old: influence of age on presentation and outcome. Am J Surg. 2012;204(6):1031-1035. [View Abstract]
- Gasior AC, St. Peter SD, Knott M, et al. National trends in approach and outcomes with appendicitis in children. J Pediatr Surg. 2012;47(12):2264-2267. [View Abstract]
- Trout AT, Sanchez R, Ladino-Torres MF, et al. A critical evaluation of US for the diagnosis of pediatric acute appendicitis in a real-life setting: how can we improve the diagnostic value of sonography? Pediatr Radiol. 2012;42(7):813-822. [View Abstract]
Codes
ICD09
- 541 Appendicitis, unqualified
- 540.9 Acute appendicitis without mention of peritonitis
- 540.0 Acute appendicitis with generalized peritonitis
- 540.1 Acute appendicitis with peritoneal abscess
ICD10
- K37 Unspecified appendicitis
- K35.80 Unspecified acute appendicitis
- K35.89 Other acute appendicitis
- K35.3 Acute appendicitis with localized peritonitis
- K35.8 Other and unspecified acute appendicitis
SNOMED
- 74400008 Appendicitis (disorder)
- 85189001 Acute appendicitis (disorder)
- 286967008 Acute perforated appendicitis
- 266439004 Acute appendicitis with appendix abscess (disorder)
FAQ
- Q: What were historical milestones in the treatment of appendicitis?
- A: In 1735, Dr. Claudius Amyand performed an appendectomy in a situation of an appendicitis within a right inguinal hernia (this is now referred to as Amyand hernia). In 1886, Dr. Reginald Heber Fitz first described what we recognize as appendicitis in his treatise "Diseases of the Vermiform Appendix." In 1887, Dr. Thomas Morton performed the first successful appendectomy under ether anesthesia. In 1889, Dr. Charles McBurney described the localization of pain from appendicitis.