Peritonitis

Question 1

How may bacteria enter the peritoneal cavity?

Answer 1

Bacteria may enter via four portals:

1. Exterior: penetrating wound, infection at laparotomy, peritoneal dialysis
2. Intra-abdominal viscera:
   
   • a) Gangrene of a viscus: e.g. acute appendicitis, acute cholecystitis, diverticulutis, ischaemic colitis
   • b) Perforation of a viscus: e.g. perforated duodenal ulcer, perforated appendicitis, rupture of intestine from trauma
   • c) post op leakage of intestinal suture line
3. Blood stream: as part of septicaemia (pneumococcal, streptococcal or staphylococcal).
4. Female genital tract: acute salpingitis, puerperal infection.

Question 2

What are the common bacteria of peritonitis of bowel origin?

Answer 2

Mixed faecal flora:

• Escherichia coli
• Strep faecalis
• Pseudomonas
• Klebsiella
• Proteus
• Clostridium
• Bacteroides

Question 3

What are the common bacteria of peritonitis of gynaecological origin?

Answer 3

Chlamydial, gonococcal or streptococcal.

Question 4

What are the pathological effects of peritonitis?

Answer 4

1. Absorption of toxins from large inflammed surface
2. Paralytic ileus leading to:

• loss of fluid
• loss of electrolytes
• loss of protein

1. Gross abdo distension –> elevation of diagphram –> liability to lung collapse and pneumonia.

Question 5

What are the clinical features of peritonitis?

Answer 5

Secondary to some precipitating lesion (e.g. appendicitis, diverticulitis). Will have its own signs.

Early peritonitis:

• severe pain -pt lies still; local or generalised tenderness (+ rebound tenderness)
• diaphragmatic irrititation > shoulder tip pain
• Vomiting
• Elevated temp, tachycardia
• No bowel sounds

Advanced: abdo distended and tympanitic, signs of free fluid, rapid (feeble) pulse, faeculent vomit, skin is moist, cold and cyanosed.

Question 6

Investigations in peritonitis?

Answer 6

Limited value: diagnosis = clinical fx.

• FBE: leukocytosis
• Serum lipase: exclude pancreatitis and prevent surgery
• CXR: free gas under diaphragm (perforated viscus). Exclude pulmonary infection.
• AXR: free gas, other cause.
• CT: free gas. Cause of peritonitis.

Question 7

DDx of peritonitis?

Answer 7

Intestinal obstruction, ureteric/biliary colic (in all patient tends to be restless).

Also: basal pneumonia, MI, intraperitoneal haemorrhage and leakage AAA.

Question 8

What are the principles of managing peritonitis?

Answer 8

1. Treat cause!
2. Pain relief: opiates e.g. IV morphine
3. Gastric aspiration: place NGT to prevent aspiration, further distension
4. IV fluid and electrolytes, +/- blood and blood products
5. ABx: broad bowel cover (penicillin+gentamicin, cephalosporin+metronidazole)
6. Surgery: if source can be removed

Question 9

How is peritoneal dialysis peritonitis diagnosed and treated?

Answer 9

Abdo pain and turbid dialysate.

Single organism: IV and intraperitoneal ABx

Multi organism: suggest perforation. Laparotmy + ABx

Question 10

What is pneumococcal peritonitis?

Answer 10

May be secondary to septicaemia from lung infection or ascending PV infection in girls 4-10y.

Clinical fx: sudden onset peritonitis with severe toxaemia and fever. Leukocytosis (20+).

Question 11

Why is bile peritonitis only rare in acute cholecystitis?

Answer 11

• unlike the appendix which rapidly gangrenes with inflammation, gallbladder thickens and is walled of by adhesions
• gallbladder has vascular supply from liver bed therefore frank gangrene unusual (unlike end artery supply by ileocolic to appendix).

Question 12

What is a complication following peritonitis?

Answer 12

Pus may collect in subphrenic spaces of in the pelvis.

Question 13

Describe the anatomy of the subphrenic region.

Answer 13

• Lies between the diaphgram above and the transverse colon + mesocolon below
• Right and left subphrenic spaces lie between the diaphgram and the liver separated by falciform ligament
• Right and left subhepatic spaces below the liver,
  
  • the right forms Morrison’s pouch
  • the left is the lesser sac; communicates with the right via foramen of Winslow.

Question 14

What is the aetiology of a subphrenic pus collection?

Answer 14

• Following generalised peritonitis (e.g. upper abdo surgery)
• Rare: from haematogenous spread, direct spread from primary lesion (e.g. empyema)

Question 15

What are the clinical features of a subphrenic collection?

Answer 15

• Usually follows generalised peritonitis by 10 - 21 days
• Symptoms: malaise, nausea, loss of weight, anaemia, pyrexia
• Common = swinging temp beginning ~10d after initial illness
• Localising: pain in upper abdo/lower chest, +/- referred to shoulder tip

Question 16

What Ix in suspected subphrenic collection?

Answer 16

FBE: leukocytosis (15-20; neutrophils predominate)

CXR:

i) Elevation of diaphragm on affected side
ii) pleural effusion / collapse lung base
iii) subphrenic gas and fluid level

U/S: diminished mobility of diaphgram, may show abscess

CT: abscess, any other pus collections.