Definition: inflammation of the peritoneal lining of the abdominal cavity, which may be localised or generalised. Generalised peritonitis can be primary or secondary.
Localised- common causes are appendicitis, cholecystitis, salpingitis, diverticulitis, abscess
Primary generalised- bacterial infection of the peritoneal cavity without obvious focus responsible
-primary pneumococcal peritonitis can occur in children
-Spontaneous Bacterial Peritonitis = ascites with neutrophils > 250/mm³, associated with cirrhosis and ascites, nephrotic syndrome. Common organisms are E.coli, Klebsiella and streptococci.
-renal failure patients on peritoneal dialysis
Secondary generalised- peritonitis spreads from a localised infective focus
-polymicrobial (usually)- appendicitis, cholecystitis, salpingitis, diverticulitis
– Intra-abdominal abscess +/- rupture
-non-bacterial- spillage of bile, blood, gastric contents
-GI perforation- peptic ulcer, diverticulum, appendix, bowel, gallbladder
-Pancreatic secretions (chemical peritonitis that often becomes secondarily infected)
-Bile duct injury (gallstones, post-op)
Strangulated, obstructed bowel
Mesenteric ischemia (can lead to septic peritonitis)
Familial Mediterranean Fever (periodic fevers and serositis- peritonitis & pleurisy)
Epidemiology: primary generalised peritonitis is rare, whilst localised and secondary generalised peritonitis are very common
-localised or generalised abdominal pain
-pain usually sharp, continuous, exacerbated by movement and coughing
Localised- signs localised to a region of the abdomen
-abdominal guarding = involuntary tensing of abdominal muscles on palpation
-rebound tenderness = greater pain on removing hand than on depressing abdomen
-percussion tenderness = pain on percussion
-positive cough test = abdominal pain when they cough
Generalised- signs generalised over abdomen
-systemic signs of toxaemia or sepsis: fever, tachycardia
-generalised guarding, rebound tenderness, percussion tenderness, positive cough test
-board-like abdominal rigidity
-bowel sounds reduced or absent (paralytic ileus)
-shock (sepsis, circulatory failure, hypovolaemia)
Spontaneous Bacterial Peritonitis– patient with ascites that deteriorates suddenly, but may be asymptomatic
Depends on cause.
Bloods: FBC (↑WCC), U&Es, LFT (cholecystitis?), amylase (pancreatitis?), CRP, clotting, Group & Save or Crossmatch (for transfusion), blood cultures, pregnancy test (ectopic?), ABG (metabolic acidosis? lactate? respiratory failure?)
Ascitic tap- to confirm Spontaneous Bacterial Peritonitis (neutrophils > 250/mm³), gram stain and culture
Erect CXR- air under diaphragm, if GI perforation
AXR- local peritoneal inflammation can cause localised ileus (paralytic bowel) with a ‘sentinel loop’ of intraluminal gas visible
Sentinel loop secondary to pancreatitis
Look for bowel obstruction
CT abdomen or laparoscopy- to diagnose cause of peritonitis
Management: depends on cause
-Urgent laparotomy/ laparoscopy may be needed to identify and treat cause, remove infected or necrotic tissue and perform copious peritoneal lavage e.g. GI perforation, appendicitis (appendicectomy)
-In acute abdomen presentation, if patient is peritonitic, they should be given antibiotics e.g. CEFUROXIME (1.5g/8h IV) + METRONIDAZOLE (500mg/8h IV/PR) (e.g. cholecystitis, salpingitis, acute diverticulitis)
-Drainage of abscesses, percutaneous (U/S or CT guided) or by laparotomy
Generalised peritonitis– IV fluid resuscitation, correction of volume and electrolyte imbalances, IV antibiotics, urinary catheter, NG tube, CVP line -as risk of sepsis and shock
Spontaneous Bacterial Peritonitis–
Antibiotics: e.g. cefotaxime (2g/6h) or tazocin (4.5g/8h) for 5 days, or until sensitivities known. Add metronidazole (500mg/8h IV) if there has been recent instrumentation to ascites.
-Septic shock, respiratory or multi-organ failure
-Tertiary peritonitis (persistence of intra-abdominal infection)
-Abscesses, portal pyaemia
-Incisional hernias (post-op), adhesions
Localised peritonitis usually resolves with treatment of cause.
Generalised peritonitis has a much higher mortality, 30-50%, increased with septic shock and multi-organ dysfunction, >70%.
Primary peritonitis has good prognosis with appropriate antibiotic therapy.
SBP overall mortality rate may exceed 30% with delayed diagnosis and treatment.