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77 Cards in this Set
- Front
- Back
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what are the 4 anaerobes found in the ailmentary tract?
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ABCF
A- actinomyces- gram + rod B- Bacteroides- gram - C- Clostridium- gram + rod F- fusobacterium- gram neg |
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what is the other pathogen that causes a biofilm besides S. viridans? what else do they have in common?
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S. epidermidis
- they can both cause subacute bacterial endocarditis |
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what two vitamins are secreted by normal flora?
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K, biotin
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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?
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Tooth decay (dental caries)
peridontal disease trench mouth h. pylori gastritis |
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what is the primary causative agents of tooth decay? how does it cause tooth decay?
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S. mutans---> by forming extracellular glucans from dietary sucrose & lactic acid... lactic acid will melt the calcium enamel.
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what is periodontal disease? what is the causative agent for gingivitis?
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inflammatory response to plaque bacteria.
Gingivitis- porphyromonas gingivalis. |
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what is trench mouth? what are the 2 causitive agents of trench mouth?
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trench mouth is acute necrotizing ulcerative gingivitis. It occurs at any age group especially w stress, malnutrition or immunodeficiency
- caused by spirochetes (Treponema- not pallidum) & fusibacterium (anaerobic bacteria) |
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what are 4 the most important clinical features of GI infections? which of these clinical features allows for the classification of GI infections?
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fever, vomiting, abdominal pain & diarrhea
diarrhea--- 3 categories: watery diarrhea, dysentery, or enteric fever. |
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what is the dominant feature of watery diarrhea?
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intestinal fluid loss
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where do the pathogenic mechanisms attack to cause watery diarrhea? what two pathogens produce the "purest form" of watery diarrhea?
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the proximal small intestine (more than 90% of physiologic net fluid absorption occurs here)
vibrio cholerae & ETEC-- causing fluid loss w/o cellular injury. |
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what pathogens are likely to cause watery diarrhea w/o N/V? Which ones have watery diarrhea + N/V?
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w/o: vibrio cholera & ETEC
w: Viral infections like rotavirus |
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how long do cases of watery diarrhea last?
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1-3 days- self limiting course.
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what is the #1 waterborne GI infection in the US? how long does the diarrhea last d/t this pathogen?
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Giardia Lamblia
lasts for weeks |
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how does dysentery compare to watery diarrhea?
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dysentery "squirts" where watery diarrhea "runs". The diarrhea in dysentery will be of a smaller volume and will contain blood & pus unlike watery diarrhea.
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what are the associated complaints w/ dysentery?
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fever, abdominal pain, cramps (invasive pathogens causing inflammation of the intestine)
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what is the #1 bacterial cause of GI infection in the US?
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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?
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Colon
Pathogens cause destructive changes in the colonic mucosa or produce an inflammatory effect by 1) direct invasion or 2) production of cytotoxins (shigella- direct invasion + toxin; EIEC- direct invasion) resolves in 2-7 days. |
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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?
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features: fever, abdominal pain, diarrhea
pt: complains of constipation in the early state. pathogen: salmonella enterica typhi. |
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which gastrointestinal disease does NOT cause diarrhea?
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infantile botulism.
causes constipation |
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what is the pathology of enteric fever?
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penetration by the organism of the cells of the distal small bowel w/ subsequent spread outside the bowel to the biliary tract, mesentery, or reticuloendothelial organs (spleen & liver- esp).
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You have a 9 year old boy present w/ pain in RLQ. You dx him with appendicitis and take him to the OR. The surgeon opens him and finds a normal appendicitis w/ enlarged & inflamed mesenteric LNs. Dx (2)
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yersinia enterocolitica & pseudotuberculosis
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Name the 2 pathogens that cause enteric fever.
name the 10 pathogens that cause watery diarrhea. name the 7 that cause dysentery? |
enteric: Salmonella typhi & yersinia enterocolitica
watery diarrhea: ETEC, EHEC, EPEC, vibrio species, c. perfringens, bacillus cereus, rotavirus, calcivirus, Giardia lamblia, Cryptosporidium dysentery: salmonella serotypes, shigella, campylobacter jejuni, EIEC, C. difficile, Entamboeba histolytica. |
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which pathogen produces AF oocysts in the stool?
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crytosporidium
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If a pt presents w/ food poisoning w/n 6 hrs, what is it d/t? later than 6 hrs?
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< 6hrs = toxin producing organism
> 6 hrs = bacteria |
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in developed countries what are the 5 MC causes of endemic GI infections?
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rotavirus (only 2x stranded RNA virus), caliciviruses, campylobacter jejunum (usu associated w/ chicken), salmonella & shigella.
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What regions of the US is vibrio cholera now endemic to?
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South & central america, the gulf coast of Louisiana & Texas.
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what are the 3 diarrheal diseases most frequently associated w/ epidemics?
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typhoid fever, cholera, & shigellosis
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what 3 pathogens were the most frequent identified causes of recent waterborne epidemics in the US?
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Giardia, Cryptosporidium & E. coli 0157:H7
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which strand of E. coli can cause TTP in adults & HUS in kids?
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E. coli O157:H7. (EHEC)
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what pathogen causes the majority of diarrhea in pts traveling from the US to Latin American countries? what is the most likely source of infection?
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50%- ETEC
10-20% shigella most likely source: incompletely or uncooked foods |
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what pathogen has a strong correlation w/ diarrhea & the consumption of salads containing raw vegetables?
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toxigenic E. coli
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what are the two ways in which food poisoning is caused?
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infection- bacteria present in food
intoxication- toxin formed before the food was consumed |
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what 3 pathogens account for more than 70% of the food poisoning outbreaks?
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salmonella, clostridium perfringens, & s. aureus
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what are the two special causes of hospital associated diarrhea?
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E. coli (in infants)
C. diff (pts on antibiotics) |
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what assay do you do to test for C. diff?
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latex agglutination test
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what are the primary goals of tx for a GI infection? what do you tx the pt w/?
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Relief of sxs & maintain fluid & electrolyte balance
tx: loperamide (antidiarrheal), antimicrobials if the causative agent is known. |
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what 5 nonviral pathogens can cause hepatitis?
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leptospira, candida, brucella, mycobacteria, pneumocystis
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what 9 viral pathogens can cause hepatitis?
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Hepatitis A-E + G
EBV CMV Yellow fever virus |
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what will the pt complain of in viral hepatitis?
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upper abdominal pain, anorexia & jaundice, N/V, dark urine & clear colored stool.
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Chronic infection with what two viruses will cause cirrhosis or hepatocellular CA?
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Hep C Virus -esp
Hep B virus |
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what is the #1 cause of liver transplant in the US?
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Hep C virus
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what is the typical description of viral hepatitis microscopically? what is the supposed mechanism that causes hepatitis to lead to hepatocellular CA?
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-panlobular infiltration w/ mononuclear cells
-hepatic cell necrosis -hyperplasia of kupffer cells -variable degrees of cholestasis the alternating damage (hepatic cell necrosis) & regeneration (hyperplasia of kupffer cells) may lead to a mutation which can lead to CA. |
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how is hepatic cell regeneration evidenced in viral hepatitis? how is liver cell damage evidenced?
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1) numerous mitotic figures
2) multinucleated cells 3) "rosette" or "pseudoacinar" formation 4) mononuclear infiltration of small lymphocytes damage: 1) hepatic cell degen & necrosis 2) cell dropout 3) ballooning of cells 4) acidophilic degeneration of hepatocytes (Councilman or apoptotic bodies. |
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what family does hepatitis A belong to? what does the virus look like?
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family: picornavirus
nonenveloped, ssRNA genome |
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what is on the 5' end of the ssRNA molecule of hepatitis A virus?
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VPG: genomic viral protein
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what is the mode of infection for hepatitis A? how long are pts contagious before exhibiting sxs of the disease?
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fecal-oral (associated w/ ingestion of food or water contaminated w/ human feces)
contagious for 1-2 weeks prior to onset of clinical disease |
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T/F
There is no carrier state of Hep A disease |
TRUE :)
it is also NOT fulminant |
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where do hep A infections occur at high frequency?
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mental hospitals, schools for the mentally handicapped & day-care centers
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what is the pathogenesis of hep A?
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alimentary tract--> multiple in intestinal mucosa --> viremia --> spread to liver --> lymphoid cell infiltration, necrosis of parenchymal cells & proliferation of kupffer cells
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the extent of _____ often coincides with the severity of hepatitis A disease
a) proliferation of kupffer cells b) necrosis of parenchymal cells c) lymphoid cell infiltration d) viremia |
b) necrosis of parenchymal cells.
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what is the average incubation period for hep A? what are the common sxs? what about on PE?
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25 days
sxs: Fever, anorexia, nausea, pain in RUQ, jaundice, dark urine & clay colored stool (1-5 days prior to clinical jaundice) PE: enlarged, tender liver; elevated serum Aminotransferase & bilirubin |
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what are those pts w/ are serologically positive for Hep A but are not jaundiced? Can you recover from this?
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anicteric hep A.
yes- chronic hepatitis is very rare and so is fulminant hepatitis. Recovery occurs w/n weeks to months. |
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what are the characteristics of relapsing hepatitis? what is another unusual variant of acute hepatitis A?
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recurrence of sxs, aminotransferase elevations, jaundice, fecal excretion of Hep A virus.
other: cholestatis hepatitis cheracterized by protracted cholestatitic jaundice, pruritus |
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how do you diagnose HEp A? what do you give to exposed individuals? when can you not give this to your pt?
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demonstrate a rise in IGM antibody between the acute illness & when the pt is recovering.
exposed: ISG: immune serum globulin containing antibody to HAV to prevent reinfection can not give ISG when the sxs have already appeared. fyi: active immunization >>>>>> better than passive immunization |
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which immunoglobulin is high during the convalescent stage in hep A?
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IgG and it will remain elevated for the rest of life
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how do you tx hepatitis A?
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supportive measures (lots of nutrition & rest)
avoid alcohol & other hepatic toxins. |
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what is the smallest DNA virus known? describe the 2 parts of the virus & the DNA
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hepatitis B virus which is a member of the hepadnaviridae family
envelope- contains Hepatitis B surface antigen Core: contains a hepatitis B core antigen & hepatitis B e antigen hep B is an enveloped DNA virus w/ cuboid symmetry that is PARTIALLY 2x stranded |
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in infected hepatocytes, what 3 things are present in the nuclei and which one is present in the cytoplasm?
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nuclei- HBcAg, HBeAg, Hepatitis B DNA
cytoplasm: HBsAg |
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in the HBV genome, what does the S gene code for? P gene? C gene? X gene?
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S gene: pre-s1 & pre-s2 which combine w/ S to code for the "middle" protein & the "large" protein
P gene: codes for DNA polymerase C gene: the 2 nucleocapsid proteins: HBeAG & HBcAg (intracellular core protein) X gene: HBxAg --- contributes to carcinogenes by binding to p53 |
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How is Hep B transmitted?
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sexually, close personal contact w/ body fluids of infected individuals, organ transplant, mother to child (via abrasions & ingestion), IV needle sharing
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what Autoimmune disease is associated w/ HBV & HCV?
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PAN: polyarteritis nodosa
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what does chronic activate hepatitis B result in (microscopically)?
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necrosis of hepatocytes, collapse of reticular framework of liver, & progressive fibrosis. --> eventually leading to postnecrotic hepatic cirrhosis
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which virus is found in nearly all heptocellular CA?
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Hepatitis B virus
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how does the replication of HBV differ from the replication of HIV?
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HIV has to bring its own reverse transcriptase to the party, HBV's reverse transcriptase is already there.
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what are the sxs associated w/ acute hepatitis B? how long is the incubation period?
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fatigue, loss of appetite, nausea, pain & fullness in RUQ, pain & swelling of the joints
super wide: 7-160 days |
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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?
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10%
25% newborns, children, & immunocompromised. |
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what is the main difference in the course of illness between HAV & HBV?
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development of chronic hepatitis
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which hepatitis virus results in a serum sickness like syndrome?
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hep B
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In pts w/ chronic hepatitis B, what other types of immune complex diseases may be seen?
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glomerulonephritis, PAN, essential mixed cryoglobulinemia
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what are the associated sxs of essential mixed cryoglobulinemia?
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arthritis, palpable purpura, GN, circulating cryoprecipitable immune complexes.
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which hepatitis Ag/ab/ IG indicates that there is an active infection? pt is infectious & actively replicating the infection? protection against/ resolution of disease? marker of past or chronic infection?
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active: HBsAg & IgM
infectious: HBeAg Resolution: Anti-HBs chronic: Anti-HBc |
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what 2 antigens are high in acute infection of HBV? what 2 antibodies are high in the convalescent stage?
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acute: HBsAg HBeAg (and HBV DNA)
convalescent: anti-HBs, anti-HBe |
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what is the best diagnostic measure for HBV?
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detection of IgM antibody to HBcAg along w/ or w/o HBsAg in serum
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when is the window period for a pt w/ HBV? what happens if the window period doesn't come within that time frame?
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6 months.
after 6 months pt is considered chronic hepatitis pt |
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what populations are indicated for preexposure prophylaxis? what is the post-exposure prophylaxis? all of HBV
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children, homosexuals, medical personnel, lab workers, injection drug users (give thes population the active immunization w/ recombinant vaccine)
post exposure: Hep B immune globulin (HBIG) |
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how do you tx chronic cases of HBV?
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interferon alpha, lamivudin, adefovir
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