SM_166b: Infectious Diseases of the Luminal GI Tract

Question 1

Primary peritonitis (spontaneous bacterial peritonitis) is ____

Answer 1

Primary peritonitis (spontaneous bacterial peritonitis) is bacterial perotinitis without an inciting event and virtually always occurs in the setting of ascites

Question 2

Secondary peritonitis is ____

Answer 2

Secondary peritonitis is bacterial contamination of the peritoneum as a result of spillage of intestinal flora

Question 3

Intraperitoneal abscess is ____

Answer 3

Intraperitoneal abscess is localized / confined (walled off) infection within the peritoneal space

Question 4

Visceral abscess is ____

Answer 4

Visceral abscess is localized infection within an organ

Question 5

Primary peritonitis (spontaneous bacterial peritonitis) nearly always develops after ___

Answer 5

Primary peritonitis (spontaneous bacterial peritonitis) nearly always develops after ascites

• Cirrhosis with ascites: 10% develop primary peritonitis
• Monomicrobial etiology: E. coli. Klebsiella, Streptococcus penumoniae, Enterococci, rarely anaerobes, others

Question 6

Primary peritonitis routes of infection are ____, ____, ____, and ____

Answer 6

Primary peritonitis routes of infection are hematogenous, lymphatogenous, translocation, and from vagina via fallopian tubes in women

Question 7

Primary peritonitis pathogenesis involves cirrhosis-related ____ consisting of ____ and ____

Answer 7

Primary peritonitis pathogenesis involves cirrhosis-related immune deficiency consisting of serum / ascitic fluid complement deficiency and neutrophil dysfunction

Question 8

Describe clinical manifestations of primary peritonitis

Answer 8

Primary peritonitis clinical manifestations

• Symptoms: fever, abdominal pain, nausea, vomiting, diarrhea
• Signs: diffuse abdominal tenderness, rebound tenderness, hypoactive / absent bowel sounds
• Cirrhotic patients: progressive encephalopathy, hepatorenal syndrome

Question 9

Primary perotonitis paracentesis shows ____ and ____

Answer 9

Primary perotonitis paracentesis shows increased neutrophils and monomicrobial infection

• Ascitic fluid neutrophil counts: > 250/mm³
• Cultures may be sterile in up to 35% of cases

Question 10

Primary peritonitis antibiotic therapy is focused on ____

Answer 10

Primary peritonitis antibiotic therapy is focused on aerobic gram-negative bacilli

Question 11

Secondary peritonitis is ____ due to ____

Answer 11

Secondary peritonitis is spillage of GI or GU microorganisms into the peritoneal cavity due to loss of integrity of the mucosal barrier

• Perforation of appendicitis, diverticulitis, peptic ulcer, intestinal neoplasm
• Traumatic perforation of bowel, uterus, bladder
• Gangrene of bowel secondary to strangulation, bowel obstruction, or mesenteric vascular obstruction

Question 12

Secondary peritonitis etiology includes ____

Answer 12

Secondary peritonitis etiology includes endogenous intestinal microorganisms (polymicrobial)

• Typical infection associated with bowel perforation averages 4.5 organisms (2.5 anaerobes, 2 aerobes)

Question 13

Describe pathogenesis of secondary peritonitis

Answer 13

Secondary peritonitis pathogenesis

• Chemical peritonitis (bile, gastric fluid, pancreatic secretions): increases susceptibility to infection by small numbers of contaminating bacteria
• Risk of infection increases with microbial load: stomach < small intestine < colon
• Local response: localized abscess or diffuse peritonitis
• Systemic response: ileus, sepsis / septic shock

Question 14

Describe clinical manifestations of secondary peritonitis

Answer 14

Secondary peritonitis clinical manifestations

• Symptoms: abdominal pain, fever, shaking chills, anorexia, nausea, vomiting
  Signs: lies quietly with knees flexed, tachycardia, rapid shallow breathing, marked abdominal tenderness, rebound tenderness, abdominal wall rigidity, hypoactive or silent bowel sounds

Question 15

Secondary peritonitis paracentesis demonstrates ____

Answer 15

Secondary peritonitis paracentesis demonstrates elevated WBC count with a left shift

• Abdominal X-rays: ileus
• Chest X-ray: free air
• Abdominal CT scan: peritoneal fluid collections, intra-abdominal abscess
• Needle aspiration of the peritoneal space

Question 16

Secondary peritonitis treatment involves ____, ____, or ____

Answer 16

Secondary peritonitis treatment involves broad-spectrum antibiotics, surgery, or percutaneous drainage of localized fluid collections

Question 17

Secondary bacterial peritonitis in the presence of ascites mortality is ____ if treated only with antibiotics and without surgery

Answer 17

Secondary bacterial peritonitis in the presence of ascites mortality is 100% if treated only with antibiotics and without surgery

• Mortality is high even with surgery

Question 18

Primary peritonitis and unncessary exploratory laparotomy leads to ____

Answer 18

Primary peritonitis and unncessary exploratory laparotomy leads to 80% mortality

Question 19

Continuous ambulatory peritoneal dialysis peritonitis pathogenesis involves ____ and ____

Answer 19

Continuous ambulatory peritoneal dialysis peritonitis pathogenesis involves contamination of the catheter by skin organisms and relapsing / recurrent peritonitis via biofilms

• Staphylococcus epidermidis and Staphylococcus aureus

Question 20

Continuous ambulatory peritoneal dialysis peritonitis presents with ____

Answer 20

Continuous ambulatory peritoneal dialysis peritonitis presents with abdominal pain and cloudy dialysate

Question 21

Continuous ambulatory peritoneal dialysis peritonitis treatment involves ____

Answer 21

Continuous ambulatory peritoneal dialysis peritonitis treatment involves antibiotics via dialysate

• May also need catheter removal

Question 22

Intraperitoneal abscess is ____ due to ____

Answer 22

Intraperitoneal abscess is infection with viable organisms and neutrophils within a fibrous capsule due to host response confining the infection to a limited space

Question 23

____ is the main pathogen implicated in intraperitoneal abscess though infection is often polymicrobial

Answer 23

Bacteroides fragilis is the main pathogen implicated in intraperitoneal abscess though infection is often polymicrobial

• Cell surface capsular polysaccharide complex is an important virulence factor
  *

Question 25

Intraperioneal abscess presents with ____, ____, ____, and ____ and is treated with ____

Answer 25

Intraperioneal abscess presents with fever, chills, abdominal pain, and tenderness over the involved area and is treated with drainage plus antibiotics

Question 26

____ often complicate underlying organ injury such as pancreatitis and infarction

Answer 26

Visceral abscesses often complicate underlying organ injury such as pancreatitis and infarction

Question 27

Describe etiology of visceral abscesses

Answer 27

Visceral abscess etiology

• Monomicrobial (hematogenous): endocarditis -> embolic infarction -> splenic abscess
• Polymicrobial via communication with the bowel lumen: pancreatic duct -> pancreatitis -> pancreatitis, biliary duct obstruction -> hepatic abscess

Question 28

____ presents as a sudden detioration 1-3 weeks after onset of pancreatitis and has increased risk with necrotizing pancreatitis

Answer 28

Pancreatic abscess presents as a sudden detioration 1-3 weeks after onset of pancreatitis and has increased risk with necrotizing pancreatitis

• Treatment requires drainage and antibiotics

Question 29

Describe liver abscess pathogenesis

Answer 29

Liver abscess pathogenesis

• Biliary: cholangitis
• Portal: associated with appendicitis, diverticulitis, IBD
• Contiguous: cholecystitis
• Hematogenous
• Traumatic: penetrating or blunt

Monomicrobial or polymicrobial depending on pathogenesis

Question 31

Splenic abscess pathogenesis is ____ and outcome is ____

Answer 31

Splenic abscess pathogenesis is hematogenous and outcome is 100% mortality if untreated

• Hematogenous: infective endocarditis

Question 32

Describe pathogenesis of acute appendicitis

Answer 32

Acute appendicitis pathogenesis

• Obstruction of appendiceal lumen: fecalith, lymphoid follicular hyperplasia, fibrosis or neoplasm
• Increasing luminal pressure result in thrombosis and lymphatic statis
• Inflammation, swelling, and ischemia of the appendix lead to necrosis and perforation of the appendix

Question 33

Describe clinical manifestations of acute appendicitis

Answer 33

Acute appendicitis clinical manifestations

• Symptoms: RLQ pain, anorexia, nausea, vomiting
• Signs: low-grade fever, rebound tenderness, and voluntary guarding progressing to abdominal rigidity

Question 34

RLQ pain, anorexia, and nausea / vomiting indicate ____

Answer 34

RLQ pain, anorexia, and nausea / vomiting indicate acute appendicitis

Question 35

McBurney’s point is painful in ____

Answer 35

McBurney’s point is painful in acute appendicits

Question 36

Acute appendicitis is diagnosed on ____

Answer 36

Acute appendicitis is diagnosed on CT

• Treat with appendectomy normally, broad-spectrum antibiotics if rupture suspected, and percutaneous drainage of abscess / delayed surgery if rupture is confirmed and abscess present

Question 38

Diverticuli are ____ usually found in the ____

Answer 38

Diverticuli are herniations of the mucosa and submucosa through the circular muscularis layer usually found in the sigmoid and descending colon

• Diverticulosis and diverticulitis

Question 39

Diverticulitis is paathogenesis involves ____ and ____

Answer 39

Diverticulitis is paathogenesis involves micro/macroscopic perforation of a diverticulum and erosion of the diverticular wall due to increase intraluminal pressure or inspissated food particles

Question 40

Complicated diverticulitis results from ____, ____, ____, ____, and ____

Answer 40

Complicated diverticulitis results from perforation, obstruction, abscess, fistula, or bleeding

Question 41

____ resembles acute appendicitis but on the left side

Answer 41

Diverticulitis resembles acute appendicitis but on the left side

Question 42

A patient with cirrhosis and portal hypertension presents with encephalopathy and tense ascites. ____ is the test most likely to diagnose spontaneous bacterial peritonitis

Answer 42

A patient with cirrhosis and portal hypertension presents with encephalopathy and tense ascites. Peritoneal fluid neutrophil count is the test most likely to diagnose spontaneous bacterial peritonitis

Question 43

A 52 yo healthy male presents with abdominal pain, nausea, vomiting and fever. On abdominal pain, you identify RLQ tenderness, guarding, and rebound. ____ is the most likely diagnosis

Answer 43

A 52 yo healthy male presents with abdominal pain, nausea, vomiting and fever. On abdominal pain, you identify RLQ tenderness, guarding, and rebound. Acute perforated appendicitis is the most likely diagnosis

Question 44

CT scan confirms acute appendicits, perforation, and peri-appendiceal abscess. Empiric therapy should be directed against ____

Answer 44

CT scan confirms acute appendicits, perforation, and peri-appendiceal abscess. Empiric therapy should be directed against aerobic Gram-negative bacilli and anaerobes