166b - Infectious Diseases of Luminal GI Tract

Question 1

What causes secondary peritonitis?

Answer 1

Spillage of GI or GU microorganisms into the peritoneal cavity

May be due to:

• Perforation
• Trauma
• Gangrene of bowel

Secondary peritonitis is usually polymicrobial (may be secondary to chemical peritonitis, ex: bile acid)

Question 2

How can the bacterial content of visceral abscesses help determine the cause?

Answer 2

• Monomicrobial
  
  • Implies hematogenous spread
  • Maybe from endocarditis w/ embolic infarction
• Polymicrobial
  
  • Implies communication with bowel lumen

Question 3

Answer 3

E - acute perforated appndicitis

• SBP unlikely to have localized pain
• Diverticuli are unlikely in RLQ
• Pancreatic pain is usually epigastric
• Cholecystitis pain is usually RUQ

Question 4

Why is it important to distinguish primary peritonitis from secondary peritonitis?

Answer 4

Need to do exploratory laparotomy for secondary peritonitis to determine the cause!

Very high mortality if secondary peritonitis is treated with abx alone

Question 5

Answer 5

C - peritoneal fluid neutrophil count

35% w/primary peritonitis will have negative culture

Question 6

Which area of the gastrointestinal tract – if injured – is most likely to result in an intraabdominal infection?

Answer 6

The colon!

Has the most bacteria

Question 7

What usually causes splenic abscesses?

Answer 7

Hematogenous spread (ex: infective endocarditis)

Question 8

How is appendicitis treated?

Answer 8

Appendectomy

• If rupture suspected, start abx
• If rupture confirmed and abscess present:
  
  • Delay surgery
  • Drain abscess percutaneously

Question 9

What paracentesis findings are indicative of secondary peritonitis?

Answer 9

Elevated WBC with “left shift” (many neutrophils)

More than one organism

Question 10

In what setting does primary peritonitis usually occur?

Answer 10

Ascites

Question 11

How can you differentiate between appendicitis and diverticulitis on on presentation?

How does the treatment differ?

Answer 11

• Appendicitis
  
  • Peri-umbilical -> RLQ pain
  • Treatment
    
    • Operate fi not ruptured
    • If rupture suspected, start abx
    • If rupture confirmed: abx, drain percutaneously, delay surgery
• Diverticulitis
  
  • LLQ pain (most likely simoid colon)
  • Treat with ABX if complicated; delay surgery

Confirm with CT before treatment

Question 12

What causes acute appendicitis?

Answer 12

Obstruction of the appendicieal lumen

May becaused by:

• Fecalith
• Lymphoid follicular hyperplasia
• Fibrosis
• Neoplasm

Question 13

A patinet with a history of cirrhosis presents wtih fever, abdominal pain and nausea

Physical exam reveals ascites

Ascitic fluid shows negative cultures and 300 neutrophils

What is your interpretation? How should you manage this patient?

Answer 13

Peritonitis! Likely primary

Even though cultures are negative, >250 neutrophils constitutes a positive culture

• Treat emperically with abx
  
  • Focus on aerobic gram negative bacilli (cefriaxone, cipro)
• Long-term preventative abx

Question 14

Answer 14

C

(These are bowel flora)

Question 15

Which bacteria is most likly to grow in intraperitoneal abscesses?

How are they treated?

Answer 15

Bacteroides fragilis

(plus others; often polymicrobial)

Drainage + abx