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61 Cards in this Set
- Front
- Back
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Describe the genome of the HIV virus.
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Diploid genome -- 2 molecules of RNA.
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What are the three structural genes that code for HIV proteins?
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env (envelope proteins gp120 and gp41), gag (capsid protein), and pol (reverse transcriptase).
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Which envelope protein is responsible for attachment of the HIV virus to the host T cell?
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gp120.
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Which envelope protein is responsible for fusion and entry of the HIV virus into the T cell?
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gp41.
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Which surface membrane proteins does HIV gp120 bind?
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CXCR4 and CCR5, also CD4.
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When is AIDS diagnosed?
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CD4+ count below 200 OR HIV+ with AIDS indicator condition (e.g., P.jirovecii infection) or CD4+:CD8+ <1.5.
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During the latent phase of HIV infection, where is the virus hanging out?
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It's replicating in the lymph nodes.
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What are the 4 stages of HIV infection?
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1. Flu-like (acute)
2. Feeling fine (latent) 3. Falling count 4. Final crisis |
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What diseases are common in HIV-positive adults with CD4+ counts <400?
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Oral candidiasis (thrush),
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What diseases are common in HIV-positive adults with CD4+ counts <200?
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Cryptosporidium spp., JC virus reactivation (causes PML -- demyelination), P. jiroveci.
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What diseases are common in HIV-positive adults with CD4+ counts <100?
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Esophageal candidiasis, Toxoplasmosis (ring-enhancing lesions in brain), Histoplasma spp. (cough, fever).
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What diseases are common in HIV-positive adults with CD4+ counts <50?
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Cryptococcus neoformans (meningitis), Mycobacterium avium-intracellularae (Tb-like disease).
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What organisms are known to cause oncologic manifestations in patients with AIDS?
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HHV-8 (Kaposi's sarcoma), EBV (Hairy leukoplakia, non-Hodgkin's lymphoma, primary CNS lymphoma), HPV (SCC of anus or cervix).
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What bugs can cause respiratory infections in patients with AIDS?
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Aspergillus, CMV, P. jiroveci, Mycobacterium avium-intracellularae.
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When should a patient with HIV begin prophylactic medication for opportunistic infections? Which drugs are used?
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When CD4+ counts drop below 200 --> TMP/SMX or Dasmone.
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When should HAART be initiated?
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HIV+ patient with an AIDS-defining illness OR CD4+ count <350.
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What does the HAART regimen consist of?
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3 drugs to prevent resistance: 2NRTIs + 1 NNRTI OR 1 Protease inhibitor OR 1 Integrase inhibitor.
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Which drugs are the protease inhibitors? What is their mechanism of action? General SE?
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"-navirs". They prevent the cleavage of the viral mRNA into its functional parts, thereby preventing the maturation of new viruses. SE: hyperglycemia, GI intolerance, dyslipidemia.
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Which HIV drug inhibits CYP450?
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Ritanovir.
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Which drugs are the NRTIs? Mechanism of action?
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Zidovudine, Lamivudine, Stavudine, Didanosine, Tenofovir, Abacavir, Emtricitabine. Competitive inhibitors of incoming nucleotides binding to RT --> termination of DNA chain.
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What do the NRTIs require to become activated?
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Must be phosphorylated by thymidine kinase.
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Which HIV drug causes hypersensitivity reactions?
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Abacavir.
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Which HIV drug(s) cause pancreatitis and peripheral neuropathy?
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Didanosine, Stavudine, Zalcitabine.
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Which HIV drug(s) cause hepatic steatosis?
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Didanosine and Stavudine.
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Which drugs are the NNRTIs? Mechanism of action?
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"--vir--"s (e.g., nevirapine, efavirenz, etravirine). Bind to RT at a different site than NRTIs. DO NOT REQUIRE phosphorylation to be active.
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Which HIV drug(s) cause a rash?
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NNRTIs.
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Which HIV drug can produce a false + drug test for cannabinoids?
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Efavirenz.
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Which HIV drug is an integrase inhibitor? Mechanism of action? SE?
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Raltegravir; inhibits HIV-1 integrase enzyme; unfavorable lipid profile.
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Which HIV drug is a CCR5 antagonist? Mechanism of action?
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Maraviroc; binds CCR5 on macrophages and prevents binding of gp120; only useful with R5 phenotype.
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Which HIV drug is used for general prophylaxis and during pregnancy to reduce risk of fetal transmission?
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ZDV.
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Which HIV drugs cause lactic acidosis?
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NRTIs.
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Which HIV drug cause bone marrow suppression and megaloblastic anemia?
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ZDV.
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A child presents with fever, sore throat, and an erythematous, sand-paper like rash. What's the bug? What part of the bug is causing the rash?
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Strep. pyogenes causing scarlet fever; pyrogenic exotoxin is responsible for the rash.
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What are the bugs of the enterobacteriaceae? What do these bugs have in common with regard to virulence, etc.?
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Salmonella, Shigella, E.coli, Klebsiella, Enterobacter, Serratia, Proteus. All are gram negative! O antigen, K antigen, H antigen (flagella - helps it get around), glucose fermenters and oxidase negative.
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What is the most common cause of Traveler's Diarrhea? Tx?
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ETEC (entero-toxigenic E.coli). TMP-SMX, fluoroquinolones.
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You have acquired a bug with a shiga-like toxin. You think it may be from infection with E.coli O157:H7. What bug is living inside your belly?
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EHEC.
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Which enteric E.coli infection occurs most commonly in children? What are the sx? What is a common place for this to occur?
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EPEC. Diarrhea. Daycare.
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Fever and bloody diarrhea due to infection with a particular E.coli bug makes you think what?
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EIEC (Entero-INVASIVE E.coli).
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Which type of enteric E.coli infection causes HUS? What is the triad?
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EHEC. Anemia, acute renal failure, thrombocytopenia.
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What are the 4 A's of Klebsiella infection? Why am I asking you a question about Klebsiella in the GI case of flashcards? What feature of Klebsiella infection is classic?
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Aspiration pneumonia, Abcess in lungs and liver, Alcholics, diAbetics. Klebsiella is an intestinal flora that can cause lung pathology if aspirated. Abundant polysaccharide capsule causes mucoid colonies to form. RED CURRANT JELLY SPUTUM.
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What characteristic feature of Proteus spp. allows it to survive?
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Urease! It converts urea to NH3 (ammonia) + CO2. Ammonia is a base, so it alkalizes the urine and allows Proteus to grow. Proteus makes stones too!
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What organisms most commonly cause UTIs?
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E. coli, Staph. saprophyticus.
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What are the urease positive bugs?
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"PUNCH-K": Proteus, Ureaplasma, Nocardia, Cryptococcus, H. pylori, Klebsiella.
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What are the diagnostic markers of a UTI?
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Positive leukocyte esterase test = BACTERIAL UTI.
Positive nitrite test = GRAM-NEGATIVE bacterial UTI. |
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What is the MOA for Sulfonamides? TMP?
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Sulfas: PABA antimetabolite -- inhibits Dihydropteroate synthetase (effectively inhibiting THF).
TMP: Inhibits DHFR -- inhibiting THF. |
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What drugs have photosensitivity reactions?
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Sulfas, tetracycline, amiodarone.
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What drugs should be avoided in people with sulfa allergies?
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Thiazides, Furosemide, Probenicid, Sulfasalazine, TMP-SMX, Celecoxib.
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What drugs can cause Stevens - Johnson syndrome? What are the sx?
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Penicillin, Ethosuximide, Carbamazepine, Sulfa drugs, Lamotrigine, Allopurinol, Phenytoin, Phenobarbital. Sx include fever, sore throat and fatigue initially, followed by a bad rash and lesions of the oral mucosa. THIS CONSTITUTES A LIFE-THREATENING DERMATOLOGICAL EMERGENCY.
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What are the clinical uses for TMP-SMX?
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UTIs, Shigella, Salmonella, MRSA infections, and prophylaxis for P.jirovecci in HIV patients with CD4+ counts <200.
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What is the mechanism of action for fluoroquinolones? What kinds of bugs does it treat?
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Inhibits DNA gyrase (Topoisomerase IV). Gram-negative rods of urinary and GI tracts!
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What is a side effect of the fluoroquinolones that you should know?
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Tendonitis and tendon rupture in adults.
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What bug is a common cause of osteomyelitis in sickle cell patients?
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Salmonella. Ewe.
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Who is more virulent, Salmonella or Shigella? Also, who is susceptible to abx treatment?
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Shigella is more virulent than Salmonella. BUT, abx tx prolongs the carrier state of Salmonella, while Shigella seems to be wiped out by abx.
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A child comes in with bloody diarrhea. A stool sample reveals comma-shaped, oxidase positive organism that grows at 42 degrees C. Diagnosis? What might this infection precipitate?
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Campylobacter jejuni. Guillain-Barrè syndrome.
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You hear about an outbreak of diarrhea in the area at a daycare center. What bug is responsible? How might it have been transmitted?
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Yersinia enterocolitica. Puppies!
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A gram-negative, comma-shaped rod causes "rice water" diarrhea. What is bug and what is the MOA used by the toxin that causes these symptoms?
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Vibrio cholerae. Toxin causes constitutive activation of the Gs receptor --> increased cAMP --> +Cl- channel = massive watery diarrhea.
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What are the sx of Clostridium difficile infection? What is the mechanism by which Clostridium difficile causes GI infection?
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Diarrhea. Spore-forming obligate anaerobe that produces two toxins:
A = binds brush border of gut. B = destroys cytoskeleton of cell and causes a PSEUDOMEMBRANOUS COLITIS. Remember, this organism DOESN'T HAVE TO INVADE TO SURVIVE. |
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What can precipitate a C. diff infection? How is it treated?
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Antibiotic use. Especially clindamycin or ampicillin. Metronidazole or oral vancomycin.
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What two bugs cause food poisoning that starts quickly and ends quickly? What types of food are they found in?
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S. aureus: custards, meats, mayonnaise (preformed toxin!)
B.cereus: reheated rice (gross). |
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What bugs found in contaminated sea food cause food poisoning?
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Vibrio parahaemolyticus and V. vulnificus.
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You are eating a reheated meat dish. What bug might you get? Also, you notice your friend is eating undercooked meat. What bug could they get?
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Clostridium perfringens. E. coli O157:H7.
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