The peritoneum is a large, serous membrane lining the abdominal cavity and covering the abdominal organs. It consists of two layers: the parietal layer lining the abdominal wall, and the visceral layer wrapping around the internal organs. Peritonitis is the acute or chronic inflammation of this membrane, usually triggered by bacterial invasion or chemical irritation.
When a hollow abdominal organ perforates, or when bacteria cross the mucosal barrier, pathogens spill directly into the sterile peritoneal cavity. The body responds with an immediate inflammatory reaction. Blood vessels in the peritoneum dilate, and capillary permeability increases, leading to an exudation of fluid containing proteins, white blood cells, and electrolytes into the peritoneal space. This fluid shift causes localized or generalized edema, commonly referred to as a third-space fluid loss. If the process is not checked, inflammatory mediators flood the systemic circulation, setting the stage for septic shock, multiple organ dysfunction, and severe electrolyte imbalances.
Classifying peritonitis helps guide appropriate medical and surgical interventions. Clinicians divide the condition into three distinct categories based on the source of contamination:
Recognizing the classic signs of peritonitis allows for prompt intervention before complications set in. Abdominal pain is almost always the primary complaint. It typically starts as a dull ache and quickly becomes severe, sharp, and constant. The pain worsens with any movement, coughing, or deep breathing.
Physical examination reveals striking findings:
Systemic symptoms accompany these local signs. Patients frequently present with high fever, chills, tachycardia, shallow breathing to avoid abdominal movement, nausea, and vomiting. Bowel sounds are typically diminished or completely absent due to paralytic ileus.
Prompt diagnostic workup confirms the clinical suspicion and identifies the underlying cause. Laboratory investigations typically show a marked leukocytosis with an elevated band count, pointing to a severe bacterial infection. Serum electrolyte panels, renal function tests, and blood gas analysis help assess the degree of dehydration, metabolic acidosis, and organ stress.
Imaging studies are crucial. An upright chest and abdominal X-ray may reveal free air under the diaphragm, confirming a hollow viscus perforation. Abdominal ultrasound or computed tomography (CT) scans provide detailed views of fluid collections, abscesses, or inflamed structures like the appendix.
As a nurse, your continuous baseline observations are vital. Monitor vital signs every fifteen to thirty minutes if the patient is unstable, watching closely for rising heart rates, falling blood pressure, and tachypnea. Keep accurate fluid balance charts, measuring strict urine output via an indwelling catheter to evaluate renal perfusion.
Peritonitis is a surgical emergency in most cases, requiring rapid stabilization and definitive treatment. Medical management begins immediately with aggressive fluid resuscitation using isotonic crystalloids to restore circulating volume and maintain blood pressure. Broad-spectrum intravenous antibiotics are started promptly to cover enteric organisms, Gram-negative bacilli, and anaerobes, even before culture results return. Nasogastric tube insertion is often necessary to decompress the stomach, reduce vomiting, and lower the risk of aspiration.
Surgical intervention aims to eliminate the source of contamination, reduce peritoneal bacterial load, and treat the underlying pathology. The surgeon performs an exploratory laparotomy or laparoscopy to seal perforations, remove infected organs like a gangrenous appendix, wash out the peritoneal cavity with warm saline, and place drains if necessary.
Post-operative care for a patient recovering from peritonitis requires meticulous attention to prevent complications and support healing. Pain management is a top priority; administer prescribed analgesics regularly to allow the patient to breathe deeply and move comfortably. Encourage early ambulation as soon as the surgical team permits, as movement helps prevent venous thromboembolism and speeds up the return of bowel motility.
Monitor surgical incision sites daily for signs of infection, such as increasing redness, swelling, foul discharge, or gaping wound edges (dehiscence). Keep strict track of intake and output, noting the return of bowel sounds and the passage of flatus, which indicates that the paralytic ileus is resolving. Provide regular mouth care since the patient may be nil per os (NPO) for an extended period, and offer emotional support to help them cope with the anxiety of a critical illness.
Despite prompt medical and surgical care, peritonitis carries a high risk of severe complications. Septic shock is a life-threatening emergency marked by profound hypotension, fever, altered mental status, and reduced tissue perfusion. Another major risk is intra-abdominal abscess formation, where localized pockets of pus collect in the peritoneal cavity, often requiring ultrasound-guided percutaneous drainage or repeat surgery. Wound dehiscence and evisceration can occur if abdominal pressure rises sharply against compromised fascial closures.
As a nurse, you must remain vigilant for subtle changes. Watch for sudden drops in blood pressure, spikes in heart rate, confusion, or decreasing urine output. If you notice signs of clinical deterioration or wound evisceration—where internal organs protrude through the surgical incision—cover the area immediately with sterile saline-soaked dressings, keep the patient calm in a low Fowler's position with knees bent, and alert the surgical team at once.