Peritonitis: Etiology and Pathophysiology

Peritonitis: Etiology and Pathophysiology

• Peritonitis is inflammation of the peritoneum, caused by contamination with bacteria, chemicals, or both.
• Primary peritonitis: Blood-borne organisms enter the peritoneal cavity, unrelated to other intraabdominal issues. Ascites (fluid buildup), as in cirrhosis, creates a bacterial breeding ground.
• Secondary peritonitis: More common, caused by perforated or ruptured abdominal organs (appendix, ulcer, diverticulitis, trauma). Organ contents (bile, enzymes, bacteria) contaminate the cavity. Initial chemical irritation is followed by bacterial peritonitis.
• Inflammation triggers fluid shifts, edema, and adhesions (body's attempt to wall off infection).

Clinical Manifestations

• Severe, continuous abdominal pain is the most common symptom.
• Tenderness over the affected area is a universal sign.
• Rebound tenderness, rigidity, and muscle spasm indicate peritoneal irritation.
• Patients often lie still and breathe shallowly due to pain exacerbation with movement.
• Other symptoms include abdominal distension, fever, tachycardia, tachypnea, nausea, vomiting, and altered bowel habits.
• Symptoms vary depending on condition severity and acuteness.
• Possible complications include hypovolemic shock, sepsis, intra-abdominal abscesses, paralytic ileus, and acute respiratory distress syndrome.
• Untreated peritonitis can be fatal.

Diagnostic Studies and Interprofessional Care

• Complete Blood Count (CBC): Used to assess elevated white blood cell count (WBC) and hemoconcentration from fluid shifts.
• Peritoneal aspiration: Fluid analysis for blood, bile, pus, bacteria, fungus, and amylase.
• Abdominal X-ray: May reveal dilated bowel (paralytic ileus), free air (perforation), or air/fluid levels (obstruction).
• Ultrasound and CT scans: Used for identifying ascites and abscesses.
• Peritoneoscopy: A method of direct peritoneum examination (useful in patients without ascites) enabling biopsy for diagnosis.
• Conservative management: For milder cases or patients at high surgical risk, comprising antibiotics, nasogastric (NG) suction, analgesics, and IV fluids.
• Surgical intervention: For severe cases, involves locating the cause, draining pus, and repairing damage (perforated organs).

Common Causes of Peritonitis (Table 47.14)

• Primary: Blood-borne organisms, cirrhosis with ascites.
• Secondary: Ruptured appendix, blunt/penetrating abdominal trauma, ruptured diverticulitis, intestinal cancer, ischemic bowel disorders, pancreatitis, perforated intestine, uterus, bladder, stomach, perforated peptic ulcer, peritoneal dialysis, postoperative complications (anastomosis breakage).

Nursing Management: Peritonitis

• Assessment: Focus on pain (location, quality), bowel sounds, abdominal distension, guarding, nausea, fever, and signs of hypovolemic shock.
• Clinical Problems: Pain, fluid imbalance, impaired GI function, risk for infection.
• Goals: Resolution of inflammation, pain relief, prevention of complications (sepsis, hypovolemic shock), normal nutrition.
• Implementation: Establish IV access and monitor for pain & response to analgesics. Position patient with knees flexed for comfort. Monitor intake/output (I&O), electrolytes, vital signs, and oxygen requirements. Administer antiemetics, maintain NPO status (possibly NG tube for decreased distension), and consider drains for open procedures.