Lecture 11: Gastroenteritis & Hepatitis Flashcards

1
Q

How would you define diarrhea clinically?

A

-3 off more loose or liquid stools per day
-lasting less than 14 days

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2
Q

Warning signs of bacterial GI infection?
What happens when warning signs of bacterial infection are absent?

A

-high fever
-blood/mucus in stool
-severe abdominal pain
- >6 stools/24h

When the warning signs of bacterial infection are absent, then you should suspect a viral cause

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3
Q

Rotavirus diarrheal disease
-caused by
-capsid
-genome
-envelope

A

-caused by Rotavirus A,B,C
-capsid: triple layer Icosahedral
-genome: dsRNA
-naked

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4
Q

Rotavirus characterized in a colorized EM

A

Show characteristics of “spoked-wheel”- like appearance

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5
Q

What virus is responsible for 50% of all acute gastroenteritis in developing and developed countries?

A

-rotavirus
**adenoviruses can cause gastroenteritis as well but not as common at rotaviruses*

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6
Q

What virus is the most common cause of severe diarrhea among unvaccinated children <5yoa?

A

Rotavirus
=human infantile gastroenteritis

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7
Q

Rotavirus transmission

A

Predominantly spread via FECAL-ORAL route
-large amounts of virus released in feces even in asymptomatic patients
-stable in the environment (obviiiiiiii))
why ?
B/c its naked and tripled capsuled

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8
Q

Rotavirus clinical presentations

A

-vomiting and watery diarrhea for 3-8 days
-fever and abdominal pain occur frequently
-dehydration in infants (undernourished)

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9
Q

Rotavirus pathogenesis

A

Infects epithelial cells of the VILLI of the SI
-lytic infection of the intestinal epithelium
-loosening of the tight junctions of intestines
-effects of the viral enterotoxin

causing loss of electrolytes and prevents reabsorption of water = diarrhea

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10
Q

Diagnosing Rotavirus

A

-direct ELISA by feces or rectal swabs
-latex agglutination test for rotavirus
-LFA: immunochromatographic
-RT-PCR

Genome: dsRNA
Capsid: triple
Naked

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11
Q

Treatment for Rotavirus

A

No anti-viral
-replace lost fluids and electrolytes

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12
Q

Prevention of rotavirus

A

2 live, oral Vaccines !!!!
-Rotarix = given at 2 & 4 months
-RotaTeq = given at 2, 4 and 6 months

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13
Q

Norovirus diarrheal disease
Caused by
Capsid
Genome
Envelope

A

Caused by:
-genus = norovirus
-species = Norwalk virus

Icosahedral
(+) ssRNA
Naked

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14
Q

What virus is globally most important non-bacterial cause of acute gastroenteritis for all ages?

A

NOROVIRUS

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15
Q

Norovirus is often associated with outbreaks regarding?

A

Outbreaks on cruise ships and ingestion of raw or improperly steamed shellfish

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16
Q

Most common cause of viral GI diarrhea in the US

A

NOROVIRUS

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17
Q

Norovirus transmission?
What about re-infections?

A
  • fecal-oral (contaminated food or water)
    -person-to-person
    -contact w/ contaminated fomites (obviiii)

Reinfections are common
-many different strains
-no life long immunity

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18
Q

Norovirus clinical presentations

A

-nausea
-acute onset non-bloody diarrhea
-some abdominal cramping
-sore throat
-vomiting = in children
-low fever, chills, muscle aches

-self-limiting (1-2 days)
-viral shedding occurs up to 2-3 weeks after symptom resolution (can be asymptomatic while still shedding)

19
Q

Norovirus diagnosis

A

Clincial diagnosis
-detection of viral RNA w/ RT-PCR in food, water, stool samples
-LFA- immunochromatographic = poor sensitivity

20
Q

Norovirus treatment

A

Oral rehydration
-patients greatest risk comes from illness-associated dehydration

21
Q

Hepatitis symptoms

A

-HYPERBILIRUBINEMIA
causes jaundice of the skin which is especially apparent in the eyes
-fatigue
-anorexia
-nausea
-vomiting
-dark urine
-clay colored stool

22
Q

-hepatitis trends in the U.S
-most common
-chronic hepatitis
-hepatocellular carcinoma
-rarely lead to liver failure

A

-HAV, HBV, HCV causes 90% of the acute cases of hepatitis in the U.S.
-HAV is the most common
-chronic hepatitis can be caused by HBV HCV
but HCV most common
-HBV&raquo_space;> HCV both are causally linked to hepatocellular carcinoma
-acute infection with with HAV HBV HCV rarely lead to liver failure

23
Q

Hepatitis A virus
-from what genus & family
-capsid
-genome
-envelope

A

-picornavirus, enterovirus 72 (hepatovirus)
-Icosahedral
-(+) ssRNA
-naked

24
Q

HAV transmission

A

-fecal-oral route
-person-to-person
-contaminated food or water
-sexual contact

25
HAV referred to as
Infectious hepatitis
26
Which hepatitis is not associated with hepatic cancer or liver failure?
HAV
27
Which hepatitis does not cause chronic infection?
HAV
28
HAV diagnosis
-ELISA = IgM -RT-PCR
29
Hepatitis B -capsid -genome and shape -envelope
Capsid: Double shelled Genome: ss/dsDNA, circular Enveloped
30
HBV transmission
-parental (needle sticks) route -mucosal (sexual) exposure to HBV+ body fluids (saliva, semen, blood)
31
Which hepatitis is the primary cause of Hepatocellular carcinoma?
HBV
32
HBV diagnosis
ELISA (for acute and chronic infection) PCR usually not used for initial diagnosis b/c it cannot discriminate b/w acute and chronic infections HBV Genome: ss/ds DNA circular Enveloped
33
HBV treatment Chronic and acute ? Do they completely cure the infection?
Acute infections: Supportive care only Chronic infections: PEG-IFN-alpha + and NRTI Drugs do not provide a complete cure for HBV Instead Drugs slow down/stop the virus from replication **”Sustained repression”** Significantly decreasing the risk of liver damage Virus titers will rebound if treatment is discontinued.
34
What do the drugs for chronic Hep B do?
**Drugs do not provide a complete cure for chronic Hepatitis B** drugs slow down/stop the virus from replicating -“Sustained repression” -Significantly decreasing the risk of liver damage -Virus titers will rebound if treatment is discontinued
35
HBV prevention
vaccines -vaccines can be use for PrEP or PEP -single-antigen recombination vaccines —— RECOMBIVAX HB = available for all ages —— Engerix-B = available for all ages —— HEPLISAV-B
36
Hepatitis C -capsid -genome -envelope
-Icosahedral -(+) ssRNA, linear -enveloped
37
Most common chronic blood borne infection in the U.S is what virus?
HCV
38
Chances of adults developing chronic hepatitis is with which strain?
HCV (50%) HBV (5%)
39
When do patients of HCV have an increased risk of developing hepatocellular carcinoma
With patients with HCV + cirrhosis
40
HCV transmission
Occurs via Parenteral or mucosal exposure to blood: -shared needles -infant born to infected mother -100% RE-INFECTION
41
HCV diagnosis
-ELISA or immunochromatographic LFA: for serology -RT-PCR: To confirm serology
42
Treatment for HCV
Treatment for HCV is generally a combination of anti-virals NOT VACCINE
43
Which virus survives freezing and heating to 140 degrees Fahrenheit?
NOROVIRUS
44
HAV treatment & prevention
-GamaSTAN S/D **Pre-exposure Prophylaxis (PrEP)** **Post-Exposure Prophylaxis (PEP)** -children routinely vaccinated