Appendicitis

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Appendicitis is defined as "Acute inflammation of the appendix. Acute appendicitis is classified as simple, gangrenous, or perforated."^[1]

Indigestible food delivered from the small intestine to the large intestine flows into the appendix and is forced out by contraction of the muscular walls of the appendix. The appendix has no known function in humans, but it is thought that, in our evolutionary ancestors, the appendix was important for digesting some tough food like tree bark. If the opening where the appendix attaches to the large intestine becomes blocked, this can lead to appendicitis, accompanied by acute pain, fever, nausea, vomiting and loss of appetite. This is a common condition, with a lifetime occurrence of about 7%.

Because the appendix has no clear role, and because it can be removed surgically without any ill effects, appendectomy is a very common operation, but it is not without risks, particularly if the appendix is perforated.

The rates of unnecessary appendectomy and of perforation have not improved over time^[2][3] in spite of increased use of laboratory tests^[3] and diagnostic imaging^[4].

Diagnosis[edit]

An Alvarado score (also called MANTRELS score) of less than 3^[5] or 5^[6][7] makes appendicitis very unlikely - at least if the pretest is low^[8]:
Two points each:

• Abdominal pain that migrates to the right iliac fossa
• Leukocytosis (more than 10000 white blood cells per microliter)

One point each:

• Anorexia (loss of appetite) or ketones in the urine
• Nausea or vomiting
• Pain on pressure in the right iliac fossa
• Rebound tenderness
• Fever of 37.3 °C (99.1 °F) or more
• Left shift or an increase in the number of immature leukocytes in the peripheral blood

X-ray computed tomography[edit]

Spiral x-ray computed tomography with oral and intravenous contrast has accuracy of:^[9]

• sensitivity 98.5%
• Specificity 98.0%

Spiral x-ray computed tomography with oral and intravenous contrast may be equally effective when using amounts of radiation.^[10]

Spiral x-ray computed tomography without radiocontrast has accuracy of:^[11]

• sensitivity 92.7%
• Specificity 96.1%

Treatment[edit]

While surgery is definitive, antibiotics may successfully treat some patients.^[12]

"Amoxicillin plus clavulanic acid was not non-inferior to emergency appendicectomy for treatment of acute appendicitis" according to a randomized controlled trial.^[13] However, peritonitis within 30 days was significantly more frequent in the antibiotic group (8% versus 2%). The recurrence rate of appendicitis within one year in the antibiotic group was 26%.

Complications[edit]

Abscess[edit]

Appendiceal abscess or phlegmon occurs in 4% of cases.^[14] It is controversial whether these patients require an appendectomy.^[14]

References[edit]