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75 Cards in this Set
- Front
- Back
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what are the 4 anaerobes found in the ailmentary tract? |
ABCF |
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what two vitamins are secreted by normal flora of the intestine?? |
K, biotin (B7)
*clotting factors also produced *B7 defic--> dementia & dermatitis |
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How do you avoid GI cancer? how about all cancer?
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GI- avoid smoked food
all cancer- avoid animal fat. (fat is converted to nitrosamide which is carcinogenic) |
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what are the 4 bacterial diseases of the upper alimentary system? |
Tooth decay (dental caries) |
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what is the primary causative agents of tooth decay? how does it cause tooth decay? |
Streptococcus mutans
bacteria colonize on teeth w/ saliva proteins = dental plaque when you eat table sugar (sucrose)--> glucose & fructose ----> glucose forms extracellular glucans glucans + bacteria plaque forms biofilm (all S. viridans sps form biofilms*) ----> fructose forms lactic acid lactic acid lowers pH, damaging crown & prevents survival of other competing bacteria
----> allowing bacterial biofilm to cause dental caries |
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what is periodontal disease? what is the causative agent for gingivitis? |
inflammatory response to plaque bacteria---> bleeding & receeding gum line--> teeth fall out |
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what is trench mouth?
what are the 2 causative agents of trench mouth? |
trench mouth is acute necrotizing ulcerative gingivitis. It occurs at any age group w/ poor mouth care- especially w stress, malnutrition or immunodeficiency |
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what is the dominant feature of watery diarrhea?
What part of the GI tract is mostly affected? |
intestinal fluid loss
proximal small intestine |
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what two pathogens produce the "purest form" (= fluid loss w/o cellular injury) of watery diarrhea? |
vibrio cholerae & enterotoxigenic E. coli (ETEC)
*both mediate effects via toxin produced |
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what pathogens are likely to cause watery diarrhea + epithelial damage (N/V, fever)? |
Viral infections like rotavirus |
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how long do cases of watery diarrhea last? |
1-3 days- self limiting course. |
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what is the #1 parasitic cause of watery diarrhea in the US?
how long does the diarrhea last d/t this pathogen? |
Giardia Lamblia
(*suspect this if diarrhea does not abate after 3 days) |
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how does dysentery compare to watery diarrhea?
*MC d/t shigella dysentery & enteroinvasive E. coli--> diff using MacConkey
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dysentery "squirts" where watery diarrhea "runs". The diarrhea in dysentery will be smaller volume, contains mucous, blood, & pus unlike watery diarrhea.
*also accompanied w/ fever, abdominal pain, cramps, & tenesmus (painful purging) |
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what is the #1 bacterial cause of GI infection in the US? |
campylobacter Jejuni |
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what organ is the focus of pathology in dysentery? How do the organisms cause dysentery? How long does it take for dysentery to resolve? |
Colon 1) direct invasion or 2) cytotoxin production (shigella= direct + cytotoxin; EIEC= direct) --> pus & blood in stools d.t damage (minimal fluid loss)
(intervene w/ ciprofloxin or azithromycin to prevent pt from becoming toxic*) |
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what are the most prominent features of enteric fever? what will the pt complain of in the early state of the infection? what is the pathogen that causes this? |
features: fever, abdominal pain, diarrhea or Yersinia Enterocolitica |
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what is the pathology of enteric fever?
*Dx during 1st wk via blood culture (more reliable) or skin bx from rose spot, after 1st week dx via stool culture |
salmonella organism penetrates cells of the distal small bowel (illeocecal region)---> spreads to blood---> infects macrophages & goes to spleen & liver (hepatosplenomegaly)---> secreted in bile & reabsorbed from gut w/ bile
*usually self-limiting but may cause septicemia--> serous disease & death |
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Name the 2 pathogens that cause enteric fever. |
enteric: Salmonella typhi & yersinia enterocolitica |
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in developed countries what are the 5 MC causes of endemic GI infections? |
rotavirus (dsRNA virus)--> watery diarrhea infant caliciviruses
campylobacter jejunum ( chicken) salmonella (raw eggs) shigella (contaminated water)
(if viral water diarrhea in adult--> norovirus*) |
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What regions of the US is vibrio cholera now endemic to? |
South & central america, the gulf coast of Louisiana & Texas. |
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what are the 3 diarrheal diseases most frequently associated w/ epidemics? |
typhoid fever (salmonella typhi) vibro cholera shigellosis (shigella dysentery)
*all spread via contaminated water |
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what 3 pathogens were the most recent waterborne epidemics in the US? |
Giardia Cryptosporidium - contaminated water E. coli 0157:H7 - cow feces- spinach contaminated
(if cruize ship---> norovirus (water) & vibro hemolyticus (undercooked shell fish) |
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what pathogen causes the majority of Traveller's diarrhea- in pts traveling from the US to Latin American countries?
what is the most likely source of infection? |
50%- ETEC
most likely source: incompletely or uncooked foods--> E. coli from raw vegetables esp* |
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what are the two ways in which food poisoning is caused? |
infection- bacteria present in food |
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If a pt presents w/ food poisoning w/n 6 hrs, what is it d/t? later than 6 hrs? |
rapid! < 6hrs = toxin producing organism |
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what 3 pathogens account for more than 70% of the food poisoning outbreaks? |
salmonella (bacteria) clostridium perfringens (bacteria) s. aureus (toxin)
(bacillus cereus & clostridium botulinum also cause rapid d/t toxin, less common) |
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what are the two special causes of hospital associated diarrhea? |
E. coli (in infants) (or Rotavirus) |
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Organisms are isolated from stool specimen. What assay do you do to test for C. difficile? |
latex agglutination test--> IDs toxin (not bacteria)
(rotavirus & giardia dx via antigen test) |
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what are the primary goals of tx for a GI infection?
what do you tx the pt w/? |
Relief of sxs & maintain fluid & electrolyte balance--> pts usually recover on own
(if adult botulinim--> give antitoxin to prevent paralysis) |
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what 9 viral pathogens can cause hepatitis? |
Hepatitis A, B, C, D, E, G |
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what will the pt complain of in viral hepatitis?
(same for all) |
RUQ pain N/V anorexia dark urine & clay colored stool jaundice (above sxs usually appear first) |
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Chronic hepatitis infection with what two viruses will cause cirrhosis or hepatocellular CA? |
Hep C Virus -esp hep D |
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What is the supposed mechanism that causes hepatitis to lead to hepatocellular CA? |
alternating damage (necrosis) & regeneration (hyperplasia of kupffer cells)--> leads to mutation--> oncogene activation**--> CA |
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what is the typical description of viral hepatitis microscopically (all types of hepatitis will have these 4 things!!)? |
-panlobular infiltration w/ mononuclear cells |
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how is hepatic cell regeneration evidenced in viral hepatitis? how is liver cell damage evidenced? |
regeneration: 1) numerous mitotic figures |
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What hep virus NEVER goes to chronicity?
what family does it belong to? what does the virus look like? |
Hep A family: picornavirus |
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Why is it likely that Hep A will be eliminated in the near future? |
only one strain (serotype) + no animal reservoir + good vaccine against it |
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what is the mode of infection for hepatitis A?
where does infection occur at high freq?
how long are pts contagious before exhibiting sxs of the disease? |
fecal-oral (associated w/ ingestion of food or water contaminated w/ human feces)
occurs in mental hospitals, schools for mentally handicapped, & day-care centers |
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T/F |
TRUE :)
it is also NOT fulminant |
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what is the pathogenesis of hep A? |
alimentary tract--> multiple in intestinal mucosa --> viremia --> spread to liver --> lymphoid cell infiltration, necrosis of parenchymal cells & proliferation of kupffer cells
(typical pathogenesity) |
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what is the average incubation period for hep A? what are the common sxs? Dx? |
25 days Fever, anorexia, nausea, pain in RUQ, jaundice, dark urine & clay colored stool (1-5 days prior to clinical jaundice) enlarged tender liver (on PE) (typical hepatitis sxs) |
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what are those pts w/ are serologically positive for Hep A but are not jaundiced?
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anicteric hep A. |
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what are the characteristics of relapsing hepatitis A? what is another unusual variant of acute hepatitis A? |
recurrence of sxs, aminotransferase elevations, jaundice, fecal excretion of Hep A virus. |
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how do you diagnose stage of Hep A?
what do you give to exposed individuals? when can you not give this to your pt? |
serology: high IgM = recent infection high IgG = previous infection OR vaccination (serum anti-HAV = immunity to future hep A) |
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How do you prevent Hep A? |
killed vaccine |
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how do you tx hepatitis A? |
supportive measures (lots of nutrition & rest-both body & liver) |
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what is the ONLY incomplete dsDNA virus known?
describe the 2 parts of the virus & the DNA |
hepatitis B virus which is a member of the hepadnaviridae family
* presence of HBcAg & HBeAg = active replication!! |
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in infected hepatocytes, what 3 things are present in the nuclei and which one is present in the cytoplasm? |
nuclei- HBcAg, HBeAg, Hepatitis B DNA |
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in the HBV genome, what does the S gene code for? P gene? C gene? X gene? |
S gene: HBsAg |
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How is Hep B transmitted? |
sexually, personal contact w/ infected body fluids (medical personal @ inc risk*) organ transplant, mother to child (via abrasion/ingestion,not direct) IV needle sharing |
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HBV causes immune-complex deposition (HBsAg-anti-HBs) what conditions can this lead to?
What types of hepatitis is HBV most notorious for causing? |
PAN: polyarteritis nodosa serum-sickness-like rash glomerulonephritis arthritis Essential mixed cryoglobinemia
causes fulminant (fast & progressive) or chronic hepatitis |
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what are the associated sxs of essential mixed cryoglobulinemia? |
arthritis, palpable purpura, GN, circulating cryoprecipitable immune complexes. |
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what does chronic active hepatitis B result in? |
necrosis of hepatocytes, collapse of reticular framework of liver, & progressive fibrosis (fibrous nodules) -->
(irreversible) postnecrotic hepatic cirrhosis, Liver failure, & hepatocellular carcinoma (**HBV found in nearly all hepatocellular CA) |
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What marker on serology indicates chronic active hepatitis B? |
HBsAg (+ IgG HBsAb & IgG HBcAb)
*IgG HBsAb is also present in pts have been vaccinated** Need IgG HBcAb to diff infection* |
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Besides being incomplete dsDNA, what else is unique about the Hep B virus? |
HBV creates its own reverse transcriptase |
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what are the sxs associated w/ acute hepatitis B? how long is the incubation period? |
fatigue, loss of appetite, nausea, pain & fullness in RUQ, pain & swelling of the joints*
*same sxs as hep A + more severe + extrahepatic manifestations* |
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what percentage of pts w/ hepatitis B infection suffer from chronic hepatitis? of that population, what percentage leads to cirrhosis, liver failure or hepatocellular ca? what 3 populations are at greatest risk? |
10% |
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what is the main difference in the course of illness between HAV & HBV? |
development of chronic hepatitis |
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What serum markers are present in an acute active Hep B infection (window period)?
Which of these is present anytime Hep B is actively replicating & highly contagious |
HBV DNA, IgM HBcAb, HBsAg, & HBeAg
active replication & highly contagious = HBeAg |
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What antibody is predominant in the convalescent stage (pt is no longer infectious, but not yet fully recovered) ? |
IgG HBeAb
(IgG HBsAb & IgG HBcAb also present) |
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What Abs are present in chronic hep B? (after pt recovered)
Which of these is necessary to differentiate a pt w/ a previous infection vs someone who has been vaccinated? |
chronic Hep B: IgG HBsAb & IgG HBcAg
* IgG HBcAb necessary to determine prior infection
(recombinant vaccine contains HBsAg--> pt has HBsAb) |
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What Ab is correlated w/ protection against/ resolution of disease? |
IgG HBsAb |
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when is the window period (predominantly IgM HBcAb) for a pt w/ HBV?
what happens if the window period doesn't come within that time frame? |
6 months. |
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what populations are indicated for preexposure prophylaxis (vaccine)?
what is the post-exposure prophylaxis? (must be given before sxs) |
children, homosexuals, medical personnel, lab workers, injection drug users (give these population the active immunization w/ recombinant vaccine) |
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how do you tx chronic cases of HBV? (no tx for acute infections) |
interferon alpha, lamivudin, adefovir
(only tx if serum shows HBsAg, HBcAg, & hep B DNA*--> recurrent infection) |
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What hepatitis virus is associated w/ the "silent epidemic" bc it slowly progresses to CHRONIC hepatitis w/o noticeable symptoms?
*leading cause of liver transplant in US** (causes cirrhosis & hepatocellular carcinoma) |
Hepatitis C virus
+ ssRNA flaviviridae family multiple serotypes |
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How is Hep C spread?
How is it dx? |
blood transfusion needle sharing organ transplant---> bc* it is not always detected on serology*--> give infected organ*
dx: serology used for HCV Ab but may be false neg (20% of time) PCR: detects HCV RNA (^ also used to monitor dz) |
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How do patients w/ Hep C present?
Most patients become chronic carriers (chronic hepatitis) w/i how long? |
similar symptoms to HAV & HBV but milder may be asymptomatic & anicteric
w/i 10- 18 yrs
chronic hepatitis--> cirrhosis---> hepatocellular carcinoma--> need liver transplant* |
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Can you prevent Hep C?
What is the tx from Hep C? When do you tx? |
no vaccine--> avoid IV drug use & screen blood products
Tx: IFN-alpha + ribavirin
* Tx when abnormal liver histology or elevated liver enzymes |
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There are several new drugs used to tx Hep C. Which one is only for genotype 1?
Which ones are protease inhibitors? |
Viekeria Pak --> only for genotype 1
Protease inhibitors: Olysio, Victrelis, Incivek (-previrs) |
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Which Hep Virus requires hepatitis B surface Ags for it's transmission (does not ever occur w/o simultaneous Hep B infection)?
*spread via blood & semen |
Hep D
ssRNA outer layer of virion derived from HBsAG can cross placenta* |
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What are the two types of delta hepatitis infections? |
simultaneous delta & hep B infection: acute or fulminant hepatitis
delta superinfection in those w/ chronic hep B: recurrent jaundice & development of chronic cirrhosis |
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How is delta hepatitis dx?
How it is prevented?
tx? |
w/i first 3 wks of infection via IgM HepD Ab for years w/ IgG HepD Ab
prevented w/ hepB recombinant HBsAg vaccine
Tx: INF-alpha
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Which hepatitis virus causes severe disease in pregnant women?
(spread fecal-oral) |
Hepatitis E
ssRNA calcivirus
*remember vowels (A & E) go through bowels (fecal oral)* |
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Which ssRNA flaviviridae virus causes mild persistant viremia?
(spread blood & semen) |
Hepatitis G |
