Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Appendicitis

The most common major surgical disease, appendicitis is inflammation and obstruction of the vermiform appendix. Since the advent of antibiotics, the incidence and the death rate of appendicitis have declined; if untreated, this disease is invariably fatal.

Age Alert

Appendicitis may occur at any age but the majority of cases occur between ages 11 and 20. It affects both sexes equally; however, between puberty and age 25, it's more prevalent in men.

Causes

·         Mucosal ulceration

·         Fecal mass (fecalith)

·         Stricture

·         Barium ingestion

·         Viral infection

·         Neoplasm

·         Foreign body

Pathophysiology

Mucosal ulceration triggers inflammation, which temporarily obstructs the appendix. The obstruction blocks mucus outflow. Pressure in the now distended appendix increases, and the appendix contracts. Bacteria multiply, and inflammation and pressure continue to increase, restricting blood flow to the organ and causing severe abdominal pain.

Inflammation may lead to infection, clotting, tissue decay, and perforation of the appendix. If the appendix ruptures or perforates, the infected contents spill into the abdominal cavity, causing peritonitis, the most common and dangerous complication.

Signs and symptoms

Appendicitis

·         Abdominal pain, which may become localized to the lower right quadrant (McBurney's point)

Clinical Tip

If a line is drawn from the umbilicus to the right superior iliac crest and divided into thirds, McBurney's point is two-thirds of the line from the umbilicus.

·         Rebound tenderness

·         Anorexia after the onset of pain

·         Nausea or vomiting

·         Low-grade fever

Rupture

·         Pain

·         Tenderness

·         Spasm, followed by a brief cessation of abdominal pain

Diagnostic test results

·         White blood cell count is moderately elevated with increased immature cells.

·         Abdominal or transvaginal ultrasound shows inflammation of the appendix.

·         Barium enema reveals a nonfilling appendix.

·         Abdominal computed tomography scan shows perforation or abscess.

Treatment

·         Nothing by mouth; parenteral fluids and electrolytes

·         High Fowler's position

·         Nasogastric intubation

·         Appendectomy

·         Antibiotics

P.161

APPENDIX OBSTRUCTION AND INFLAMMATION

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