Peritonitis
Introduction
Peritonitis is an inflammation of the peritoneum, the thin layer of tissue that lines the inside of the abdomen and covers most of the abdominal organs. This condition can be life-threatening if not treated promptly and appropriately. It can be caused by a variety of factors, including bacterial or fungal infection, injury, or underlying medical conditions. Understanding the etiology, pathophysiology, clinical presentation, diagnostic methods, and treatment options for peritonitis is crucial for effective management and improved patient outcomes.
Etiology
Peritonitis can be classified into primary, secondary, and tertiary types based on its etiology.
Primary Peritonitis
Primary peritonitis, also known as spontaneous bacterial peritonitis (SBP), occurs without an apparent source of infection within the abdomen. It is most commonly seen in patients with liver cirrhosis and ascites. The most frequent causative organisms are Escherichia coli and other Gram-negative bacteria.
Secondary Peritonitis
Secondary peritonitis is the result of an infection that spreads from an intra-abdominal source, such as a perforated peptic ulcer, ruptured appendicitis, or diverticulitis. It can also occur due to trauma or surgical complications. The microbial flora in secondary peritonitis is typically polymicrobial, including both aerobic and anaerobic bacteria.
Tertiary Peritonitis
Tertiary peritonitis is a persistent or recurrent infection that occurs after adequate treatment of primary or secondary peritonitis. It is often associated with immunocompromised patients and involves more resistant organisms, such as Pseudomonas aeruginosa and Candida species.
Pathophysiology
The pathophysiology of peritonitis involves a complex interplay of host immune responses and microbial factors. When the peritoneum is exposed to infectious agents or irritants, an inflammatory response is triggered. This response includes the release of cytokines, chemokines, and other inflammatory mediators, leading to increased vascular permeability, leukocyte infiltration, and formation of exudate.
In primary peritonitis, bacteria translocate from the gastrointestinal tract into the peritoneal cavity, often facilitated by increased intestinal permeability in patients with liver disease. In secondary peritonitis, the infection spreads directly from a perforated or inflamed organ. The resulting inflammation can cause adhesions, abscess formation, and systemic sepsis if not controlled.
Clinical Presentation
The clinical presentation of peritonitis can vary depending on the underlying cause and the patient's overall health. Common symptoms include:
- Severe abdominal pain and tenderness
- Abdominal distension
- Fever and chills
- Nausea and vomiting
- Tachycardia and hypotension
On physical examination, patients may exhibit signs of peritoneal irritation, such as rebound tenderness and guarding. In severe cases, signs of septic shock, including altered mental status and multi-organ dysfunction, may be present.
Diagnosis
The diagnosis of peritonitis involves a combination of clinical evaluation, laboratory tests, and imaging studies.
Laboratory Tests
Laboratory tests that aid in the diagnosis of peritonitis include:
- Complete blood count (CBC) showing leukocytosis
- Blood cultures to identify causative organisms
- Ascitic fluid analysis in cases of ascites, including cell count, Gram stain, and culture
Imaging Studies
Imaging studies are essential for identifying the source of infection and assessing the extent of intra-abdominal pathology. Common imaging modalities include:
- Abdominal X-ray to detect free air or fluid
- Ultrasound to evaluate for ascites and abscesses
- Computed Tomography (CT) scan for detailed visualization of intra-abdominal structures
Treatment
The treatment of peritonitis involves a combination of antimicrobial therapy, surgical intervention, and supportive care.
Antimicrobial Therapy
Empirical broad-spectrum antibiotics should be initiated promptly, targeting both aerobic and anaerobic organisms. The choice of antibiotics may be adjusted based on culture results and the patient's clinical response. Commonly used antibiotics include third-generation cephalosporins, carbapenems, and metronidazole.
Surgical Intervention
Surgical intervention is often required in cases of secondary peritonitis to control the source of infection. This may involve procedures such as:
- Laparotomy or laparoscopy to repair perforations
- Drainage of abscesses
- Resection of necrotic or infected tissue
Supportive Care
Supportive care measures are crucial for stabilizing patients with peritonitis. These include:
- Intravenous fluid resuscitation to maintain hemodynamic stability
- Pain management
- Nutritional support
- Monitoring and management of organ dysfunction
Prognosis
The prognosis of peritonitis depends on several factors, including the underlying cause, the patient's overall health, and the timeliness of treatment. Early diagnosis and appropriate management are associated with better outcomes. However, peritonitis can lead to significant morbidity and mortality, particularly in elderly or immunocompromised patients.
Prevention
Preventive measures for peritonitis include:
- Prophylactic antibiotics in high-risk patients, such as those with cirrhosis and ascites
- Timely surgical intervention for conditions that may lead to secondary peritonitis
- Strict aseptic techniques during abdominal surgeries and procedures