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Appendicitis and Peritonitis Overview

Jun 15, 2025

Overview

This lecture covers the causes, symptoms, diagnosis, treatment, and complications of appendicitis and peritonitis, with key exam questions for review.

Appendicitis

  • Appendicitis is inflammation of the appendix, usually caused by obstruction (e.g., fecalith, tumor, or infection).
  • Obstruction leads to inflammation, ischemia (impaired blood flow), and bacterial overgrowth.
  • Key symptom: right lower quadrant pain at McBurney's point.
  • Other symptoms: rebound tenderness, loss of appetite, nausea, vomiting, and fever.
  • Diagnosis: CT scan and elevated white blood cell count.
  • Treatment: NPO (nothing by mouth), IV fluids, antibiotics, and appendectomy (removal of appendix).
  • Surgical approach is usually laparoscopic unless ruptured; rupture may require open surgery.
  • Complications include peritonitis and perforation.
  • Sudden relief of pain in appendicitis can indicate appendix rupture (red flag).

Peritonitis

  • Peritonitis is inflammation of the peritoneum (membrane around abdominal organs) due to bacterial contamination.
  • Causes include trauma, infection, or perforation of organs (e.g., appendix, diverticulitis, peptic ulcer).
  • Key symptom: rigid, board-like abdomen.
  • Other symptoms: abdominal pain, nausea, vomiting, fever, rebound tenderness, and tachycardia.
  • Diagnosis: abdominal x-ray, CT scan, or ultrasound.
  • Treatment: NPO, NG tube for stomach decompression, IV fluids, antibiotics, analgesics.
  • Surgery and intra-abdominal lavage are needed if caused by a ruptured organ.
  • Monitor closely for sepsis, a serious complication of peritonitis.

Key Terms & Definitions

  • Appendicitis — inflammation of the appendix.
  • Peritonitis — inflammation of the peritoneum.
  • McBurney’s point — location in the right lower quadrant of the abdomen, key in diagnosing appendicitis.
  • Rebound tenderness — pain when pressure on the abdomen is released.
  • NPO — nothing by mouth.
  • Fecalith — hard mass of feces causing obstruction.
  • Intra-abdominal lavage — washing out the peritoneal cavity.

Action Items / Next Steps

  • Review signs, symptoms, and treatments for appendicitis and peritonitis.
  • Remember key complications (rupture, sepsis).
  • Know the location of McBurney’s point and its clinical importance.
  • Complete any assigned medical-surgical nursing readings related to these disorders.