Special Surgery 23. Signs and Causes of Peritonitis. Perforation of Luminal Organs: Symptomatics, Diagnostics, Treatments

I. Peritonitis: Definition, Classification and Causes

Definition

Peritonitis = acute inflammation of the peritoneal cavity
Usually infectious, but can be chemical at the beginning
Chemical irritation → bacterial contamination → sepsis if untreated
Surgical emergency if secondary peritonitis or hollow-viscus perforation is suspected

Classification

Primary peritonitis

Inflammation/infection of peritoneum without surgically treatable intra-abdominal source
Spontaneous bacterial peritonitis (SBP)
Occurs mainly in cirrhosis + ascites
Usually monomicrobial
No perforated organ
Treatment mainly medical: antibiotics + albumin in selected cirrhotic patients

Secondary peritonitis

Inflammation of peritoneum due to another intra-abdominal source
Most common clinically important surgical form
Usually polymicrobial: Gram-negative + anaerobes +/- Gram-positive bacteria
Needs resuscitation + antibiotics + source control

Perforated peptic ulcer
Perforated appendicitis
Perforated diverticulitis
Perforated colon cancer
Ischemic bowel necrosis
Trauma: blunt or penetrating
Iatrogenic perforation: endoscopy, surgery, drains
Postoperative anastomotic leakage
Peritoneal dialysis-related contamination
Biliary leakage, pancreatic leakage, infected necrosis

Tertiary peritonitis

Persistent or recurrent peritoneal infection after apparently adequate treatment
Occurs in critically ill or immunocompromised patients
Often low-virulence or resistant organisms
High mortality

Extent

Localized peritonitis:

Inflammation limited by omentum, adhesions or adjacent organs
Example: appendiceal abscess, localized diverticular abscess

Diffuse/generalized peritonitis:

Free contamination of whole peritoneal cavity
Rigid abdomen, sepsis, shock risk
Usually requires emergency operation or urgent source control

Pathophysiology

Peritoneal irritation → severe pain + reflex abdominal wall spasm
Bacterial contamination → cytokine release → SIRS/sepsis
Inflammation → capillary leakage + third spacing into peritoneal cavity
Third spacing → hypovolemia + electrolyte disturbance + renal hypoperfusion
Untreated source → septic shock → ARDS, AKI, liver failure, DIC, multiorgan failure

II. Signs, Symptoms and Diagnostics

Clinical Features

Severe abdominal pain
Diffuse pain if generalized peritonitis
Localized pain in early appendicitis/diverticulitis/cholecystitis
Pain worsens with movement, coughing or transport
Pain can radiate to shoulder/back → diaphragmatic irritation
Nausea, vomiting
Abdominal distension
Paralytic ileus → absent bowel sounds
Fever, tachycardia
Hypotension, confusion, oliguria → sepsis/shock

Peritoneal Signs

Abdominal tenderness
Guarding:

Involuntary tensing of abdominal wall muscles during palpation
Suggests peritoneal irritation

Rigidity:

Board-like abdomen
Typical for diffuse peritonitis or perforated ulcer

Blumberg sign / rebound tenderness:

Pain after sudden release of abdominal compression

Percussion tenderness
Patient lies still, avoids movement
Digital rectal/vaginal exam when pelvic pathology is possible

Laboratory Diagnosis

CBC: leukocytosis/neutrophilia or leukopenia in severe sepsis
CRP, procalcitonin ↑
Electrolytes, urea/creatinine: dehydration, AKI
Liver enzymes, bilirubin, amylase/lipase depending on suspected source
Lactate, blood gas: tissue hypoperfusion/sepsis severity
Coagulation tests: preoperative assessment, DIC
Blood cultures before antibiotics if this does not delay treatment
Group and screen/crossmatch if surgery likely

Imaging

CT abdomen/pelvis with IV contrast = best test in stable patients

Shows free air, free fluid, abscess, inflammation, ischemia
Helps localize perforation/source
Helps differentiate pancreatitis, obstruction, ischemia, diverticulitis

Erect chest X-ray / abdominal X-ray:

Free air under diaphragm = pneumoperitoneum
Fast and useful if CT not immediately available
Normal X-ray does not exclude perforation

Ultrasound:

Free fluid, gallbladder disease, appendicitis in thin/pregnant patients
FAST in trauma/unstable patients
Less sensitive for free air

Diagnostic laparoscopy:

When diagnosis remains uncertain but surgical abdomen is likely
Can become therapeutic

Do not delay urgent operation/source control in an unstable patient with clear generalized peritonitis.
Acute pancreatitis is usually not treated by early laparotomy; surgery is reserved for specific complications such as infected necrosis, bleeding, ischemia or abdominal compartment syndrome.

III. Perforation of Luminal Organs

Definition

Full-thickness rupture of a hollow/luminal organ wall
Leakage of gas, digestive content, bile, feces or pus into peritoneal cavity
Perforation → chemical peritonitis → bacterial peritonitis → sepsis
Degree of contamination depends on organ and time:

Gastroduodenal content: chemical irritation initially, then bacterial contamination
Small bowel: mixed intestinal bacteria
Colon/rectum: heavy fecal contamination, high sepsis risk

Common Causes by Organ

Site	Typical causes	Exam clue
Stomach / duodenum	Peptic ulcer, NSAIDs, malignancy, endoscopy	Sudden epigastric pain, board-like abdomen, free subdiaphragmatic air
Appendix	Acute appendicitis with necrosis/perforation	RLQ pain, fever, localized or diffuse peritonitis
Small bowel	Trauma, obstruction/strangulation, Crohn disease, ischemia, foreign body	Diffuse pain, obstruction signs, sepsis if delayed
Colon	Diverticulitis, cancer, obstruction with ischemia, ischemic colitis, colonoscopy	LLQ pain in sigmoid diverticulitis, fecal peritonitis, severe sepsis
Rectum	Trauma, iatrogenic injury, foreign body, cancer	Pelvic sepsis, rectal bleeding, extraperitoneal air/abscess possible
Gallbladder / biliary tract	Acute cholecystitis perforation, bile duct injury/leak	Bile peritonitis, RUQ pain, postoperative bile leak

Symptomatics of Perforation

Sudden severe abdominal pain
Pain becomes diffuse as contamination spreads
Shoulder-tip pain if diaphragm irritated
Guarding, rebound tenderness, rigidity
Nausea, vomiting
Abdominal distension, ileus
Fever, tachycardia
Hypotension/shock in advanced cases

Complications

Sepsis and septic shock
Hypovolemia due to third spacing
Electrolyte disturbance
ARDS
Acute kidney injury
Liver failure
DIC
Intra-abdominal abscess
Wound infection, fascial dehiscence
Adhesions → later bowel obstruction
Enterocutaneous fistula after severe infection/reoperation

IV. Treatment: Resuscitation, Antibiotics and Source Control

Initial Management

ABCDE assessment
Oxygen if hypoxic/shock
Two large-bore IV cannulas
Fluid resuscitation with balanced crystalloids
Correct electrolyte and acid-base disturbances
Nil per os (NPO)
Nasogastric tube if vomiting, ileus or upper GI perforation suspected
Urinary catheter to monitor urine output
Analgesia: opioids are allowed; do not withhold pain relief
Early surgical consultation and anesthesia/ICU involvement if septic

Antibiotic Therapy

Start broad-spectrum IV antibiotics early after cultures if possible
Do not delay antibiotics in sepsis
Cover Gram-negative rods + anaerobes +/- Gram-positive organisms
Examples:

Piperacillin-tazobactam
Ceftriaxone or cefotaxime + metronidazole
Carbapenem for severe sepsis or high resistant-organism risk

Antifungal therapy is not routine
Consider antifungal therapy in high-risk patients:

Immunosuppression
Recurrent/postoperative peritonitis
Prolonged ICU stay
Unresolved intra-abdominal infection

After adequate source control: usually short course antibiotics, often 3-5 days
Persistent fever/sepsis after 5-7 days → search for uncontrolled source/abscess/leak

Source Control Principles

Source control = eliminate contamination source + drain infected fluid + restore/control anatomy
Needed in secondary peritonitis and perforated hollow viscus
Timing:

Immediate/urgent if diffuse peritonitis, sepsis, shock, ischemia or free perforation
Image-guided drainage possible for selected localized abscesses in stable patients

Approaches:

Laparoscopy: selected stable patients, early/limited contamination, diagnostic uncertainty
Laparotomy: unstable patient, fecal peritonitis, severe contamination, ischemia, complex source
Percutaneous CT/US-guided drainage: localized abscess, bridge to elective surgery

Operations by Cause

Perforated gastric/duodenal ulcer:

Laparoscopic/open closure
Omental patch (Graham patch) if suitable
Biopsy/excision if gastric ulcer suspicious for malignancy
Postoperative PPI + H. pylori testing/eradication

Perforated appendicitis:

Appendectomy + lavage/drainage if needed
Appendiceal abscess/phlegmon in stable patient may be treated initially with antibiotics +/- percutaneous drainage

Perforated diverticulitis:

Localized abscess → antibiotics +/- percutaneous drainage
Diffuse purulent/fecal peritonitis → emergency sigmoid resection
Hartmann procedure in unstable/high-risk patients
Primary anastomosis +/- diverting stoma in selected stable patients

Perforated colon cancer:

Oncologic resection if patient condition allows
Stoma/diversion or damage-control strategy if unstable/septic

Ischemic/necrotic bowel:

Resection of non-viable bowel
Second-look laparotomy/laparoscopy if bowel viability uncertain

Anastomotic leak:

Drainage + antibiotics + source control
Endoscopic/percutaneous treatment in selected contained leaks
Reoperation, washout, repair/resection/diversion if generalized peritonitis or sepsis

Peritoneal Lavage and Drainage

Remove pus, bile, gastric content or fecal contamination
Warm saline lavage used selectively until gross contamination cleared
Drain abscess cavities or high-risk leak sites selectively
Routine drains after every contaminated operation are not always required

Postoperative and ICU Care

Monitor vitals, urine output, lactate, inflammatory markers
Continue fluids, electrolyte correction and nutrition
Early enteral nutrition when feasible
VTE prophylaxis
Watch for persistent sepsis:

Intra-abdominal abscess
Missed perforation
Anastomotic leak
Necrotic bowel
Resistant organisms