Gastrointestinal Infections IV

Question 1

How common is H. pylori infection?

What demographic is particularly impacted?

Serious progression?

transmission?

Answer 1

• very common; most common in older adults (>60)
  
  • wider range duodenal ulcers
  • gastric (55-65)
• more common in males (2:1)
• long-term infection
  
  • gastric adenocarcinoma
  • lymphoma
• Person-to-person

Question 2

Pathogenesis, including H. pylori virulence factors?

Answer 2

• Bacterial virulence factors:
  
  • corkscres motility
  • pH sensing
    
    • urease (will raise pH when senses it’s too low)
  • vacA
    
    • vaculation & death of surface epithelial cells
  • cagA gene
    
    • affects intracellular signalling pathways of host cell
• Inflammation
  
  • cytokines– reduce stomatostatin and increase gastrin levels
    
    • get more acid– futher damage

Question 3

Diagnosis H. pylori infection?

Treatment?

Prevention?

Answer 3

• Diagnosis
  
  • recognize common signs and symptoms
  • serological test
  • C₁₃ labeled urea test
  • Endoscopy and biopsy
  • Stool EIA antigen test
• Treatment
  
  • see pharmacology notes

Question 4

Answer 4

Candida albicans

Question 5

Answer 5

Peptic ulcer disease

Question 6

Answer 6

Urease

Question 7

What is viral hepatitis?

Which etilogical agents are fecal-borne?

Answer 7

A serious inflammatory disease of the liver associated wtih poor sanitation and is most common in developing countries

• Hepatitis A and E (not endemic in US.)
  
  • single stranded RNA virusess

Question 8

Symptoms fecal-borne hepatitis?

Answer 8

• Incubation 14-45 days
• distaste for cigarettes
• Children usually asymptomatic (84-94%)
• Adults; 66%- jaundice
  
  • 5-25% asymptomatic
• Initial symptoms
  
  • fever, malaise, fatibue, headache, anorexia, nausea, vomiting, pain in right upper quadrant, hepatosplenomegaly
• Classic symptoms
  
  • cholestasis, jaundice (icterus), dark urine, clay-colored stools, elevated levels of AST, ALT , and bilirubin

Question 9

What demographics are most susceptable fecal-born hepatitis?

Answer 9

• highest incidence of infection 25-39 yr olds
  
  • no chronic carrier state
• HAV shed virus 10 days before symtoms begin
• HAV and HEV incidence higher in crowded living conditions
• HEV is not in the united states
• HEV has mortality rate 10x that of HAV (1-2%)
  
  • even high if woman is infected while pregnant (20%)

Question 10

Common routes HAV is acquired?

Answer 10

• eating raw/undercooked shellfish
• daycare facilities
• areas with poor sanitation practices
• travel to developing countries
• MSM
• Healthcare institutions
• food service
• illicit drug users

Question 11

Pathogenesis of fecal-borne hapatitis infection?

Answer 11

• Infects cells lining oropharynx and the intestines
• viremia
• infects liver from blod
• virus is released into the bile and is eventually shed int eh stools
• usually self-limiting disease

Question 12

Diagnosis fecal-borne hepatitis?

Treatment?

Prevention?

Answer 12

• Diagnosis
  
  • look for classical symptoms
  • EIA for IgM and IgG for HAV
    
    • positive for IgM = acute HAV infection
    • positive for IgG= prevoius HAV infection (or infection)
• Treatment
  
  • Supportive treatment and rest
• Prevention
  
  • vaccination recommended all children 12 mo. or older
    
    • killed viral vaccine
  • Immunoglobulin given w/in 2 weeks of infections (lessens severity)
  • Passive immunization - human immune serum globulin

Question 13

What viruses cause blood-borned hepatitis?

describe the type of virus

Answer 13

• HBV; partially double stranded DNA virus
• HCV; ssRNA virus
• HDV; ssRNA (a viroid)

Question 14

Symptoms HBV and HCV?

Answer 14

• longer incubation HBV (7-160 days)
• many patients asymptomatic
  
  • if asymptomatic on primary infection , more liekly to develop chronic infections
    
    • more likely w/ HCV
  • newborns and children are less likely to become symptomatic
    
    • more likely to develop chronic hepatitis
• acute infection: like fecal-born hepatitis
  
  • later symptoms can be more sever than HAV
• Fulminant hepatitis (inflammation & starts dying) more likely if HBV & HDV coinfection
  
  • severe liver damage
  • ascites and bleeding
  • liver shrinkage rather than hepatomegaly
• Chronic hepatitis
  
  • more common HCV than HBV
  • can suffer from cirrhosis & liver failure
• Primary hepatocellular carcinoma
  
  • HBV is associated wtih 80% of cases of liver carcinoma
  • HCV can also cause liver cancer

Question 15

Most common routes HBV is transmitted?

Answer 15

• transmission
  
  • contact with HBV infcted body fluids (blood, saliva, semen, vaginal secretions, breast milk)
    
    • percutaneous routes
    • sexual contact- most common route
    • perinatal contact (child birth, breast feeding)
    • later one gets HBV the less likely they will have a chronic HBV infection

Question 16

Whta is the leading infectious indication for liver transplant?

Answer 16

Hepatitis C

While ago, we couldn’t test blood for Hep C, so a good number of older people got Hep C from blood transfusions

Question 17

Most common routes HCV is transmitted?

Answer 17

• Percutaneous routes- most common
  
  • injuection drug use- most common
  • blood transfusion
  • hemodialysis
  • renal transplantation
• perinatal
• sexual transmission - very low

Question 18

How is HDV transmitted?

Answer 18

• coinfection with HBV or super infection of patients with chronic HBV
• more liekly to have severe liver disease
• transmission by percutaneous routes
  
  • IV drug users

Question 19

Diagnosis of blood-borne hepatitis infections?

Answer 19

• Initial diagnosis
  
  • signs cholestasis, altered liver enzymes, bilirubin, an alkaline phosphatase elevated
  • liver enzymes elevated (AST, ALT)
• Acute disease HCV - RNA tests positive, serology negative
  
  • if RNA and serological tests are positive, it is toughto know if acute or chronic disease
• Serology for HDV
• HBV order test for
  
  • HBsAg detects HBV antigen (acute)
    
    • marker for virus circulating
  • Anti-HBs and Anti-HBc detect antibodies to HBV antigens

Question 20

Describe the serology of HBV

Answer 20

• 3 tests you order
  
  • HBV antigen assay: HBsAg
  • Antibodies to HBV: Anti-HBs and Anti-HBc
• Acute
  
  • positive for HBsAg, Anti-HBc IgM
• Window
  
  • positive for Anti-HBc IgM
• Early convalescence
  
  • positive for Anti HBs and Anti-HBc IgG
• Late convalescence
  
  • positive for Anti-HBc IgG
• Chronic: HBsAg positive for 6 monts
  
  • chronic persistent
    
    • positive for HBsAg, Anti-HBcIg, Anti-HBe
    • probably less severe
  • Chronic active
    
    • positive for HBsAg, Anti-HBc IgG, HBeAg
• Vaccination only include HBsAg

Question 21

Treatment and prevention for blood-born hepatitis?

Answer 21

• Treatment
  
  • supportive care for acute cases of hepatitis
  • chronic HBV
    
    • see pharmacology notes
  • chronic HCV
    
    • depends on patients & HCV genotype
    • watchful waitign OR treatmetn (see pharmacology notes)
• Prevention
  
  • give Hepatitis B vaccine to prevent both HBV and HDV infections

Question 22

Answer 22

• Hep B (5-10%) and Hep C (60-70%) can cause chronic, but C is more likely

Question 23

Answer 23

• Hep E

Question 24

Answer 24

• 1- Early acute
  
  • for window period, you would not se any “surface”

Question 25

Answer 25

• Window period
  
  • s are negative
  • would have them come back to do blood work to see if they develop the antibody to s

Question 26

Answer 26

• 3- convalescent HBV

Question 27

Answer 27

• 5- vaccinated for HBV
  
  • negative for antibody to core

Question 28

Answer 28

• because surface antigen has been there for 6 months, they are chronic
• because unable to make antibody to the envelope antigen
  
  • likely chronic active

Question 29

Answer 29

• Hep C
• – were vaccinated against Hep A, or they had it in the past & resolved it
• – vaccinated against Hep B b/c antibody to surface is positive but antibody to core is negative