This document discusses acute peritonitis, including its definition, causes, routes of spreading, microbiology, and types (localized vs diffuse). Peritonitis is defined as inflammation of the peritoneum, which can be caused by bacterial or chemical sources. Common causes include gastrointestinal perforation or translocation. Gram-negative bacteria are frequently involved and can cause endotoxic shock. Peritonitis may spread via the bowel, female genital tract, or hematogenously. Localized peritonitis remains confined to areas like the pelvis or subphrenic space due to anatomical barriers, while diffuse peritonitis spreads more widely in the peritoneal cavity.

1. Acute Peritonitis : Etiology
Name : Vihari Vichakshana Rajaguru
Group : No 32
4th
year 2nd
semester

2. What’s peritoneum ?
• Made of mesothelium.
• Largest cavity in the body
• Composed of flattened polyhedral cells,
resting on fibro-elastic membrane.
• Beneath the peritoneum lies loos areolar
tissue which has rich supply of capillaries and
lymphatics.

4. Introduction
• Defined as inflammation of the peritoneum.
• May be localized or generalized.
• In most cases there is bacterial invasion hence
when it is said that there is peritonitis 
Bacterial peritonitis.
• Even in patients with non bacterial peritonitis
like those d/t Pancreatitis  Eventually gets
infected d/t transmural spread from the gut.

5. Causes
• Bacterial  Gastrointestinal & non-
gastrointestinal
• Chemical Bile, Barium
• Allergic  Starch
• Traumatic  Operative Handling
• Ischaemic  Strangulated bowel, vascular
occlusion
• Miscellaneous  Familial Mediterranean fever.

6. Routes of spreading
• Bowel perforation 

• Transmural Translocation 

• Exogenous contamination 

• Female genital tract 

• Hematogenous spread 

7. Microbiological aspect
• Peritoneal infection is usually caused by more than 2
strains of bacteria.
• Gram negative  endotoxins (lipopolysaccharides) 
TNF
 Tissue perfusion
Endotoxic shock
• These organisms are present in the lower GI tract and
do respond to Penicillins rather to metronidazole and
clindamycin and cephalosporins

8. Non gastrointestinal causes
• Pelvic infection via fallopian tubes are one of the
major causes of Non GI cause of peritonitis.
• The most common organisms being Chlamydia or
gonococcus.
• Chlamydia  Fitz Hugh Curtis Syndrome
(perihepatitis)
• Fungal Peritonitis  In severely ill patients or
Immuno-compramised patients.

9. Microorganisms
• GASTRO INTESTINAL SOURCE:
– E.coli
– Streptococci
– Bacteroids
– K.pneumonia
• NON GASTROINTESTINAL SOURCE:
– Chlamydia
– Neisseria gonorrheoa
– Streptococci
– Mycobacterium & Fungal

10. Localized Peritonitis
• Anatomical and pathological factors help confining infection to
localized areas.
• Greater sac is divided into
– Subphrenic space
– The pelvis
– Peritoneal cavity proper.
• Supracolic and infracolic (division by transverse colon and
transverse mesocolon)
• When supracolic compartment overflows, it does so over to
infracolic region/paracolic gutters/pelvis.

11. Peritoneum
• Inflammed peritoneum loses sheen
Fibrin
• Flakes of fibrin appear  loops of intestine become
adherent to each other
Leukocytes
• Outpouring of serous fluid rich in leukocytes which later
becomes frank pus  Ileus  Prevents spread of infection
 Greater omentum seals the area.

12. Diffuse peritonitis
• Factors favoring spread of peritonitis.
– Speed of peritoneal contamination
– Ingestion of food.
– Virulence of infecting organism
– Young children with small omentum.
– Disruption of localized collection
– Immune deficiency
• With appropriate treatment localized disease will
resolve
– About 20% progress to abscess.