Table of Contents · 11 sections
In a nutshell. Peritonitis is inflammation of the peritoneum leading to systemic inflammatory response syndrome (SIRS), sepsis, and multiple organ dysfunction syndrome (MODS). Primary is hematogenous (SBP in cirrhosis), secondary results from organ perforation/inflammation (90% of cases), and tertiary is persistent following surgery. Diagnosis is based on clinical presentation (board-like rigidity, Blumberg's sign), ultrasound/CT, and laparoscopy. Treatment: early surgery (source control, lavage, drainage) + empiric broad-spectrum antibiotics + sepsis intensive care.
1. Definition and classification
Peritonitis is inflammation of the visceral and parietal peritoneum accompanied by endogenous intoxication and multiple organ failure. The peritoneum has an area of 1.7–2 m² and a huge absorptive capacity, making peritonitis a "major fire" in the body.
By etiology
- Primary (spontaneous) — hematogenous or lymphatic infection without perforation; seen in patients with liver cirrhosis (SBP, 10–30%), nephrotic syndrome, and in children.
- Secondary — 90% of cases; result of hollow organ perforation, destruction (appendicitis, cholecystitis, diverticulitis, pancreatitis), trauma, or anastomotic leakage.
- Tertiary — persists or recurs after adequate treatment of secondary peritonitis; often involves resistant flora and fungi in debilitated patients.
By spread
- Localized circumscribed (abscess) or uncircumscribed (1 anatomical region).
- Generalized: diffuse (2–5 regions), widespread (> 5).
By type of exudate
- Serous, fibrinous, purulent, hemorrhagic, biliary, fecal, urinary, chemical (in pancreatitis).
2. K. S. Simonyan's phases of peritonitis
| Phase | Timeframe | Clinical Practice |
|---|---|---|
| Reactive | 0–24 h | Localized pain, muscle rigidity, peritoneal signs; SIRS is mild |
| Toxic | 24–72 h | Endotoxemia, intestinal paresis, tachycardia, hypotension; "Hippocratic facies" |
| Terminal | > 72 h | Multiple organ failure, septic shock, "false sense of improvement" of the abdomen |
3. Pathogenesis
Microbial or chemical irritation → exudation and peritoneal vascular paresis → hypovolemia, hypoalbuminemia → absorption of endotoxins and cytokines → SIRS → sepsis → microcirculatory disorders, DIC, multiple organ failure. Intestinal paresis leads to bacterial translocation and additional influx of endotoxins.
4. Clinical presentation
- Constant abdominal pain, worsening with movement or coughing.
- Nausea, vomiting, dry mouth.
- Delayed stool and gas passage (paralytic ileus).
- Tachycardia, tachypnea, hypotension.
- Anterior abdominal wall rigidity ("board-like abdomen").
- Positive peritoneal signs: Shchetkin-Blumberg, Voskresensky ("shirt sign"), Kulenkampff.
- Diminished/absent bowel sounds on auscultation.
5. Diagnostics
- Complete blood count — neutrophilic leukocytosis, left shift, ↑ CRP, ↑ procalcitonin.
- Biochemistry — electrolytes, creatinine, lactate (> 2 mmol/L is an indicator of hypoperfusion).
- Plain radiography — free gas under the diaphragmatic dome (perforation).
- Ultrasound — free fluid, abscesses.
- Contrast-enhanced CT — gold standard: perforation source, abscesses, pneumoperitoneum.
- Diagnostic laparoscopy — when the clinical picture is unclear.
- Paracentesis with ascitic fluid analysis — in suspected SBP (neutrophils > 250/µL).
6. Mannheim Peritonitis Index (MPI)
Prognostic scoring system, totals 8 factors. Important for deciding on an "open abdomen" and staged lavage.
- Age > 50 years — 5.
- Female gender — 5.
- Organ failure — 7.
- Malignant tumor — 4.
- Duration > 24 h — 4.
- Colonic source — 4.
- Generalized peritonitis — 6.
- Exudate: seropurulent — 0; turbid-putrid — 6; fecal — 12.
Score: < 21 points — mortality 0–10%; 21–29 — 20–50%; > 29 — > 50%.
7. Differential Diagnosis
- Acute intestinal obstruction.
- Myocardial infarction with radiation (abdominal variant).
- Diabetic ketoacidosis, acute adrenal insufficiency.
- Basal pneumonia (pleural signs).
- Renal colic, ectopic pregnancy, ovarian apoplexy.
8. Treatment
Preoperative preparation (2–4 h)
- Crystalloid infusion 20–30 ml/kg; in shock, vasopressors (norepinephrine).
- Empiric antibiotic therapy within 1 h of diagnosis (sepsis bundle).
- Correction of electrolytes, acid-base balance, hypoproteinemia.
- Nasogastric tube, urinary catheterization to monitor diuresis.
Surgery
- Laparotomy (or laparoscopy if an appropriate source is identified).
- Source control: appendectomy, closure of perforation, resection with anastomosis or stoma.
- Peritoneal lavage — irrigation of the abdominal cavity with 6–10 L of warm saline, removal of fibrin.
- Drainage of all compartments (subhepatic, lesser pelvis, subdiaphragmatic).
- If MPI > 26, fecal peritonitis, instability — "open abdomen", staged lavages (programmed lavage).
Antibiotic Therapy
- Community-acquired mild-to-moderate: ceftriaxone + metronidazole; ertapenem.
- Severe/nosocomial: piperacillin/tazobactam or carbapenem + vancomycin if MRSA is suspected.
- Duration — 4–7 days from source control, guided by clinical status/CRP/PCT.
- Antifungal therapy — in tertiary peritonitis, prolonged antibiotic therapy.
9. Intensive Care of Sepsis
- Surviving Sepsis Campaign bundle: 1st hour — lactate, blood cultures, antibiotics, fluid resuscitation; 3rd hour — repeat lactate.
- Target: MAP ≥ 65 mmHg, urine output > 0.5 ml/kg/h, decreasing lactate.
- Vasopressors — norepinephrine (first line), add vasopressin 0.03 units/min.
- Hydrocortisone 200 mg/day in vasopressor-refractory shock.
- Glucose control 7.8–10 mmol/L, stress ulcer prophylaxis, LMWH for VTE prophylaxis.
10. Complications
- Sepsis, septic shock, AKI, ARDS.
- Intra-abdominal abscesses (subdiaphragmatic, interloop, pelvic).
- Enteric fistulas, evisceration.
- DVT/PE.
- Adhesive disease in the long-term period.
11. FAQ
When is peritonitis treated without surgery?
Only primary peritonitis (SBP): ceftriaxone + albumin. In all other cases, surgery is mandatory; antibiotics alone are ineffective.
What is programmed relaparotomy?
Planned repeated lavages every 24–48 h in severe peritonitis (MPI > 26, fecal source, hemodynamic instability). An alternative is relaparotomy on demand.
How quickly should antibiotics be started?
Within the first hour of diagnosing sepsis/septic shock — each hour of delay increases mortality by 7.6%.
Why does postoperative ileus develop?
Peritoneal inflammation, sympathetic activation, electrolyte disturbances. Prevention: early enteral nutrition, prokinetics, epidural anesthesia.
What are the criteria for drain removal?
Serous discharge < 50 ml/day, absence of purulent drainage, normalization of temperature and leukocyte count — usually on days 5–7.
See also: Acute Abdomen · Appendicitis · Gallstone Disease and Cholecystitis · Antibiotics · Surgery Catalog · Clinical Scales