Infectious diseases (GI infections) Flashcards
What organisms can lead to Blood and WBCs in stool? (8)
Salmonella (poultry) Campylobacter (most common cause) E. coli 0157:H7 (HUS) Shigella (2nd most common association w/ HUS) Vibrio parahaemolyticus (shellfish and cruise ships) Vibrio vulnificus Yersinia (high affinity for iron) Clostridium difficile
What is the best initial test for infectious diarrhea?
Stool lactoferrin (greatest sensitivity and specificity), Blood and/or fecal leukocytes
What is the most accurate test for infectious diarrhea?
Stool culture
What organisms cause infectious diarrhea w/ no blood or WBCs in stool?
Viral Giardia (camping/hiking) Cryptosporidiosis (AIDS) Bacillus cereus (vomiting) Staphylococcus (vomiting)
Why do bacillus and staphylococcus lead to nausea/vomiting in addition to diarrhea?
Intake of preformed toxin
How are mild and severe infectious diarrhea treated?
Mild: Oral fluid replacement
Severe: Fluid replacement and oral antibiotics (Cipro)
How does “severe” infectious diarrhea present? (6)
Hypotension Tachycardia Fever Abdominal pain Bloody diarrhea Metabolic acidosis
How is Giardia treated?
How is Cryptosporidiosis treated?
Giardia: Metronidazole ,tinidazole
Cryptosporidiosis: Treat underlying AIDS, nitazoxanide
Hepatitis D exists exclusively in those who have active viral replication of ______ __
Hepatitis B
Which types of hepatitis are spread by sex, blood, or perinatal transmission?
Hepatitis B, C, and D
Which types of hepatitis are spread by food and water?
“You Ate hepatitis A; you Eat hepatitis E”
Hepatitis A and E
All forms of acute hepatitis present with…
Jaundice Fever, weight loss, and fatigue Dark urine Hepatosplenomegaly Nausea, vomiting, abdominal pain
What diagnostic findings are seen with acute hepatitis? (3)
Increased direct bilirubin
Increased ratio of ALT to AST
Increased alkaline phosphatase
What is the presentation of a Scombroid infection?
How is it treated?
Rapid onset
Wheezing, flushing rash
Found in fish
Treat with antihistamines
What test correlates best with an increased likelihood of mortality in acute hepatitis?
Prothrombin time (increased risk of fulminant hepatic failure and death)
What is the best initial diagnostic test for hepatitis A, C, D, and E?
IgM antibody for the acute infection and IgG antibody to detect resolution of infection
How is disease activity of hepatitis C assessed?
PCR for RNA level (tells the amount of active viral replication)
Describe the following for an acute or chronic hepatitis B infection... Surface antigen: E-Antigen: Core antibody: Surface antibody:
Surface antigen: Positive
E-Antigen: Positive
Core antibody: Positive IgM or IgG
Surface antibody: Negative
Describe the following for a resolved, old, past hepatitis B infection... Surface antigen: E-Antigen: Core antibody: Surface antibody:
Surface antigen: Negative
E-Antigen: Negative
Core antibody: Positive IgG
Surface antibody: Positive
Describe the following for someone vaccinated for hepatitis B infection... Surface antigen: E-Antigen: Core antibody: Surface antibody:
Surface antigen: Negative
E-Antigen: Negative
Core antibody: Negative
Surface antibody: Positive
Describe the following for someone in the window period of a hepatitis B infection... Surface antigen: E-Antigen: Core antibody: Surface antibody:
Surface antigen: Negative
E-Antigen: Negative
Core antibody: Positive IgM, then IgG
Surface antibody: Negative
Which serologic marker becomes abnormal first after acquiring hepatitis B?
Surface antigen (measure of actual viral particles)
Which serologic marker for hepatitis B most directly correlates with amount or quantity of active viral replication?
Hepatitis B e-antigen is directly correlated with the degree of DNA polymerase activity
Lack of which serologic marker indicates that a patient is no longer at risk for transmitting hepatitis B infection?
Lack of surface antigen
Which serologic marker in hepatitis B infection is the strongest indicator of active viral replication?
E-antigen
What is the difference between testing for e-antigen and testing for DNA polymerase?
e-antigen is a qualitative test (it is simply positive or negative)
DNA polymerase is a quantitative test (gives a level that can have a lot of variability)
What is the most common method of hepatitis B transmission worldwide?
Perinatal transmission
What is the purpose of testing for viral load in hepatitis B and C?
Best test for determining whether there has been a response to therapy or a failure in therapy
Hepatitis __ and __ resolve spontaneously over a few weeks
A and E
Hepatitis B becomes chronic in __% of patients regardless of treatment
10%
Acute hepatitis C should be treated with… (which decrease likelihood of developing chronic infection)
Interferon, ribavirin, and either boceprevir or telaprevir
What is chronicity for hepatitis B defined as?
Persistence of surface antigen for more than 6 months
If patients with chronic hepatitis B are positive for ________ with an elevated level of ____ __________ they should be treated
e-antigen; DNA polymerase
Treatment for chronic hepatitis B is with any one of which 6 drugs?
Entecavir, adefovir, lamivudine, telbivudine, interferon, or tenofovir
What adverse effects are associated with interferon? (5)
Arthralgia/myalgia Leukopenia Thrombocytopenia Depression Flu-like symptoms
Genotypes 2 and 3 of hepatitis C are treated with…
Oral sofosbuvir and ribavirin
Genotype 1 of Hepatitis C is treated with…
Oral ledipasvir and sofosbuvir for 12 weeks
What is the goal of chronic hepatitis therapy?
Reduce DNA polymerase to undetectable levels
Convert patients with e-antigen to having anti-hepatitis e-antibody
The presence of ____ on liver biopsy is indication to begin therapy for either hepatitis B or C right away
fibrosis
Why is there no way to determine duration of infection with hepatitis C?
No equivalent of the surface antigen test
What is the only form of acute hepatitis that should be treated?
Hepatitis C
Everyone born between ____ and ___ is tested for hepatitis C regardless of risk factors
1945-1965
When should patients be treated for chronic hepatitis C (which minimized the need to perform liver biopsy)?
When there is an elevated PCR-RNA viral load
