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Micro 3 > viral infections I > Flashcards

viral infections I Flashcards

1
Q

what is hepatitis and what are the three main clinical presentations?

A

Inflammation of the liver

  • acute
  • chronic
  • fulminant
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2
Q

what are some lab tests that are elevated with hepatitis

A

bilirubin, AST (aspartate aminotransferase), ALT (alanine amino transferase)

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3
Q

symptoms of acute viral hepatitis

A
  • jaundice- skin and eyes (b/c increased bilirubin)
  • dark urine
  • acholic stool- grey or white stool due to reduction of bile secretion
  • prodrome- 1-2 wks before jaundice-vomiting, headache. myalgia, fatigue, pharyngitis and mild fever
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4
Q

why do we get elevated levels of bilirubin in the blood when there is hepatitis

A

rbc’s heme break down to bilirubin and liver makes bilirubin more water soluble to be excreted in the urine but if the liver is not working, there is no place for the bilirubin to go

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5
Q

acute viral hepatitis biochemistry

A

> 3 mg/dL bilirubin, commonly 5-20
bilirubin in urine
enzymes hi- ALT, AST =USUALLY HIGHER THAN THAT OF OTHER HEPATITIS CAUSES (MAYBE UP TO 1000)

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6
Q

chronic viral hepatitis

A
  • hepatitis what does not resolve in 6 mo.
  • predispose to hepatocellular carcinoma and cirrhosis- immune system recognize antigen in liver and kill it leading to damage and then liver regenerates over and over to cause cirrhosis- the over-generation of the cells can lead to hepatocellular carcinoma (3-5%)
  • can take up to 15-40 yrs -often asymptomatic
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7
Q

fulminant viral hepatitis

A
  • rapid, sever, hep
  • massive hepatic necrosis and ENCEPHALOPATHY that leads to confusion, disorientation and coma
  • edema- cerebral, brainstem compression, GI bleeds, sepsis and organ failure
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8
Q

what are the 5 types of hepatitis and how are they transmitted? are they results of chronic infection

A

A, E = fecal/oral- no chronic infection

B, C, D = body fluids- yes chronic infection

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9
Q

hepatitis A symptoms

A

-jaundice, diarrhea, vomiting, liver inflammation that usually resolves in 2 months

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10
Q

what virus causes hep A

incubation

A

-picornavirus (ssRNA) via oral/fecal
incubation time- 28 days
DOES NOT CAUSE CHRONIC HEP AND VERY RARELY CAUSES FULMINANT HEP

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11
Q

diagnosis and prevention of Hep a

A
  • diagnosis -acute infection- Igm antibodies against HAV (hep a virus)
  • anti- HAV IgG for past infection
  • prevention
  • vaccines since 1995- 2 dose schedule
  • vaccine is also used as post-exposure prophylaxis
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12
Q

hepatitis B virus- what does it look like under the microscope

A
  • has tubes and spheres that are incomplete and non-infectious particles but show that there is an active infection
  • dane particles that are complete virons- infectious
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13
Q

what is hep B virus caused by? what are some characteristics and parts of the virus?

A

-hepatDNAvirus
-has partially dsDNA genome
-has reverse transcription in a part of the life cycle
-parts: HBsAG (hep B surface antigens) = surface antigen of dane particles and tubes and spheres
HBcAG (core)-not soluble but we are able to test for antibodies to it
HBe Ag- DNA that is water soluble so can find and test in blood

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14
Q

how do you diagnose Hep B

A
  • look at viral antigens and HBV antibodies

- HBsAg- is a sign of ACTIVE INFECTION- both chronic and acute

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15
Q

what does the serology look like in an ACUTE Hep B viral infection

A
  • Igm antiHBc up at first and then tapers as IgG anti-HBc increases
  • HBs Ag is obviously high at first and then as the virus clears AntiHBs rises
  • HBeAg rises at start of infection and then anti-Hbe come in and replaces it
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16
Q

what does the serology look like in an CHRONIC Hep B viral infection

A
  • as pt is infected the HBsAg rises and stays up to a plateau
  • AntiHBc rises and also stays up to a plateau
  • IgM anti HBc increases and then plummets because not clearing the virus
  • anti HBs antibody not made
  • HBeAg also stays up for chronic and replicating infections and we see antiHbe antibodies when HBe is present but not replicating***
17
Q

if someone is vaccinated against Hep B virus , what would you expect to see? where do you also have this finding?

A
  • positive HBs antibody

- also see positive HBs antibody with someone previously infected

18
Q

how do you distinguish between a patient who is acutely infected with Hep B virus and one that has a chronic infection

A

-acute has presence of IgM

19
Q

how is hep B virus transmitted? what’s important to note about age of infection and risk of chronic infection?

A
  • bodily fluids-sexual, needle stick, at birth
  • half of adults are asymptomatic- acute hep B often milder than acute hep A
  • the older you are, the less likely you are to develop a chronic infection
20
Q

treatment for Hep B virus?

A
  • none for acute infections
  • chronic- lamivudine- reverse transcriptase inhibitor, famcylovir/adefovir dipivoxil- nucleoside inhibitor, interferon- alpha
21
Q

prevention of Hep B virus?

A
  • vaccine made up of purified HbsAg protein and give IM at 3 doses
  • children born from moms that have unknown or known HBV infection are given HBsAG vaccine and HBIG 12 hrs post birth
22
Q

Hepatitis C virus
what family?
kind of virus?
transmission?

A
  • flavivirus family
  • enveloped
  • ssRNA
  • blood borne and bodily fluids (IV drug users!!! -45% of IV drug users between ages of 18 and 45 infected)- sexual is rare
23
Q

diagnosis of Hep C virus

A
  • expected chronic infection
  • screening test- antibody-based test for anti-HCV antibodies
  • confirm via nucleic acid test for viral genome
24
Q

disease outcomes for HAV or HBV

A
  • chronic infection- 70%
  • acute only- 15%
  • rapid progression to cirrhosis- 15%
25
Q

treatment and prevention for Hep C

A
  • sofosbuvir- rna dependent rna polymerase =super expensive

- prevention- no vaccine, reduce hi risk behavior, screen blood supply

26
Q

Hep D virus
RNA type?
encodes?
what’s special about it?

A
  • small ssRNA genome- circular
  • encodes only two proteins- delta-short and delta long antigens that cover the viron
  • special- needs a helper virus= Hep B proteins at surface -therefore, Hep D can only infect pt that have been or currently are infected by Hep B
27
Q

transmission of Hep D
what’s important to note about the B/D combo
what’s important to note about hep D and hepatocytes

A
  • body fluids
  • 5% of HBV carriers
  • makes you more likely to become a fulminant hep
  • Hep D virus is the only one that directly injures hepatocytes
28
Q

diagnosis, treatment, prevention of Hep D virus

A
  • elisa to detect anti HDV antibodies on the delta antigens
  • treatment- none
  • prevention- since HDV requires HBV then vaccination against HBV will prevent it
29
Q

hep E virus
what virus fam?
transmission-
chronic/acute infection?

A
  • Hepevirus
  • ssRNA
  • transmitted thru fecal-oral route
  • no chronic infection
30
Q

what population should we be worried about when it comes to hep E?

A

-pregos

31
Q

treatment and prevention for hep E

A
  • supportive

- prevention- clean water and proper food handling

32
Q

what causes the acute infection and damage in hepatitis infections?

A

-Cytotoxic t lymphocyte destruction of hepatocytes

33
Q

window period for HBV

A
  • no free surface antigen (HBsAg) and no anti HBs detectible

- when they are all bound

34
Q

what portion of adults with acute HBV will progress to chronic? neonates?

A
  • 10%

- 90%

35
Q

what indicates that HBV is chronic and REPLICATIVE?

A
  • have IgG that’s not turning to IgM to HBcAB

- HBeAg present but no anti-HBe

36
Q

combo of hep b and hep D is called?

A

superinfection =more severe disease (fulminant hep)

37
Q

what does hep b provide to hep D?

A
  • surface antigen
38
Q

in terms of prevention of infection by hep B virus, what does hep b vaccine contain? what type of immunity?

A

-HBsAg, humoral

Micro 3 (8 decks)

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