HIV Flashcards Preview

MFM Written Boards > HIV > Flashcards

Flashcards in HIV Deck (76):
1

What type of cells are the target of HIV infection?

T cells with CD-4 and CCR5 receptors, macrophages/monocytes

2

How does HIV utilize a cells machinery to replicate?

After binding CD4 or CCR5 receptors on a cell surface, viral RNA is transcribed into DNA using the cell’s reverse transcriptase. The DNA is then integrated into the infected cell’s genome.

3

Pathophysiology of HIV

HIV primarily infects T lymphocytes that express the CD4 antigen, resulting in a progressive loss of these cells and impairment of cellular immunity as well as humoral immunity. When CD4 lymphocytes are sufficiently depleted there is the progression to AIDS, characterized by the development of opportunistic infections and malignancies.

4

How rapidly does HIV replicate?

Infected CD4 population doubles every 15 days.

5

While HIV1 is the most common strain of HIV seen in the US, where is HIV2 most commonly seen?

West Africa

6

How does HIV2 differ from HIV1?

HIV2 is less virulent but more indolent, with decreased transmission rates

7

How quickly can HIV be detected after a primary infection?

21 days

8

How common are symptoms during the acute phase?

40-90% have symptoms within 2w of exposure

9

What are the primary symptoms with acute HIV?

Fever, LAD, pharyngitis, rash, and myalgias/arthralgias

10

Following the acute infection, what is the typical latency period before symptoms develop?

7-11 years

11

What is the typical rate of CD4 drop/year during the latency period?

50/year

12

Diagnosis of HIV

Screening ELISA is positive and is followed by a confirmatory positive Western blot.

13

When is rapid testing for HIV indicated?

Previously untested women presenting in labor, or those expected to be delivered for maternal or fetal indications before results of conventional testing can be obtained.

14

Sensitivity & specificity, PPV of rapid HIV testing

The sensitivity and specificity of each of the available rapid testing assays ranges from 95% to 100%, while the positive predictive value depends on the prevalence of disease in the population. In a population with low prevalence of disease, the positive predictive value is low while the false- positive rate is high. For example, with a prevalence of disease of *1% in the population, the positive predictive value of the test may be as low as 60%.

15

What should be done if a rapid HIV test is positive?

ARV prophylaxis should be offered without waiting for the results of the confirmatory conventional tests.

16

How does viral load affect transmission rates?

27% with VL >100,000, <20

17

Diagnosis of AIDS

Regardless of symptoms, a CD4 <200 cells/mm3 or the presence of an AIDS-defining illness in an HIV-positive person is an AIDS diagnosis.

18

What is the recommended approach to HIV screening in pregnancy? Opt-in or opt-out?

An opt-out approach has been shown to increase acceptance rates for HIV testing in pregnant women and is the recommended approach to universal prenatal screening.

19

After initial prenatal testing for HIV, who should have a repeat test? When?

28-32 wksHigh-risk behaviorHigh-prevalence areaPreviously declined testing

20

Risk factors for perinatal HIV transmission

Closely related to viral load at the time of delivery. Other risk factors: Low CD4+ T-lymphocyte countLack of ARV therapyBiologic phenotype of the virusSubstance abuseProlonged duration of membrane ruptureHCV coinfectionSexually transmitted infections (STIs)Preterm birthChorioamnionitis

21

Fetal complications of HIV

Possible increased risk of preterm delivery if on a protease inhibitor (PI) containing regimen, but no increased risk of FGR, stillbirth, or low Apgar scores.

22

Effect of pregnancy on HIV progression

Pregnancy has no clear effect on HIV progression. A transient but clinically insignificant decrease in the CD4+ T-lymphocyte count has been described.

23

Antepartum perinatal HIV transmission risk

25-40%

24

Intrapartum perinatal HIV transmission risk

60-75%

25

Postpartum breastfeeding transmission risk

14%

26

Transmission rate of HIV without ART

25%

27

Transmission rate of HIV on AZT monotherapy

10%

28

Transmission rate of HIV with ART

1.2%

29

If you had only intrapartum AZT and C/S available, what would be the transmission rates?

5-8% with ZDV, 2% with C/S + ZDV

30

What is the transmission rate once SROM has occurred?

2%/hour

31

Is there still a benefit of C/S once labor/SROM occurs?

The benefit is lessened significantly, so give loading dose of AZT and proceed with C/S

32

HIV Stage A1

(Used by UCH CHIP team)Asymptomatic, acute, primary HIV, or PGL (persistent generalized lymphadenopathy)CD4 >/= 500/uL

33

HIV Stage A2

Asymptomatic, acute, primary HIV, or PGLCD4 200-499/uL

34

HIV Stage A3

Asymptomatic, acute, primary HIV, or PGLCD4

35

HIV Stage B1

Symptomatic, not A or C conditionsCD4 >/= 500/uL

36

HIV Stage B2

Symptomatic, not A or C conditionsCD4 200-499/uL

37

HIV Stage B3

Symptomatic, not A or C conditionsCD4

38

HIV Stage C1

AIDS-indicator conditionsCD4 >/= 500/uL

39

HIV Stage C2

AIDS-indicator conditionsCD4 200-499/uL

40

HIV Stage C3

AIDS-indicator conditionsCD4

41

Preconception counseling for HIV+ women

-Initiate or modify ART, avoiding potentially teratogenic agents-Opportunistic infection prophylaxis as indicated by CD4 count-Appropriate immunizations-Optimize maternal nutritional status, initiating folic acid supplementation-Screen for and treat STIs-Screen for psychological and substance abuse disorders Advise how to optimize the chance of conception while minimizing the risk of sexual transmission-Prevent unwanted pregnancies

42

Initial prenatal visit for HIV+ patients - H&P

-Complete medical/obstetric/gynecologic-History of prior or current ARV use-Symptoms of AIDS - fever, night sweats, weight loss, a new persistent dry cough, diarrhea, refractory vaginal candidiasis, oral candidiasis, new outbreaks of herpes.-Assess need for prophylaxis against opportunistic infections such as Pneumocystis pneumonia (PCP) or Mycobacterium avium complex (MAC).-Complete physical exam, if CD4 <200 cells/mm3, specifically evaluate for thrush, HSV, lymphadenopathy, or a rash.Discuss risk of transmission and factors that modify those risks.Discuss risk and benefits of ART for both the patient and the fetus.Educate on safe sex practices with condoms.

43

Initial prenatal visit for HIV+ patients - Labs

-HBsAg, HBsAb, HBcAb, HCV ab -CMV and Toxo antiboides-CBC w/ diff, LFTs, Cr, ur protein-VDRL/RPR, gc/ct-PPD.-Early 1 hr gtt if prolonged protease inhibitor (PI) exposure.-Pap smear-CD4 cell count-Plasma HIV RNA level-Resistance testing: before starting ART, if initial HIV RNA level above the threshold for resistance testing on tx-Genotyping is preferable to phenotyping because it is less expensive, it has a faster turnaround time, and a greater sensitivity for detecting mixtures of wild-type and resistant virus.-HLA B-5701 testing if abacavir use is anticipated.

44

PPD testing if CD4 < 200 cells/mm3

A negative test may be the result of anergy, and pts should have a CXR to r/o tb

45

Monitoring HIV during pregnancy

-Q trimester: CBC w/ diff, LFTs, Cr, ur protein-CD4 cell count - at least q 3 mos-Plasma HIV RNA levels - 2 to 4 weeks after initiating/changing therapy, q mo until HIV RNA levels are undetectable, and then at 34-36w to determine mode of delivery-VL should decrease by 1 to 2 logs within 4 weeks of starting therapy.-Resistance testing: if suboptimal viral suppression after ARV initiation, if persistently detectable plasma VL on therapy which previously suppressed the virus to undetectable

46

Delivery recommendations for pregnant women w/ HIV

l Women with a viral load >1000 copies/mL should becounseled regarding the benefit of planned cesarean delivery at 38 weeks to reduce the risk of transmission. With effective antiretroviral therapy leading to undetectable viral load, planned cesarean delivery for viral load >1000, and formula feeding, the risk of perinatal transmission is reduced to <2%.

47

AZT treatment for newborn

The newborn should receive AZT for at least the first four to six weeks of life (dose 2 mg/kg qid).

48

Dx of HIV in the infant

May take up to 18 mos to clear maternal antibodies, thus a qualitative HIV-1 DNA PCR assay is usedShould be performed at a minimum age of 14-21 days, at 1-2 mos, and at 4-6 mosHIV may be excluded with 2 or more negative tests, w/ one at >14 d and >1 mo.Many confirm w/ an HIV antibody test at 12-18 mos.

49

After birth, how long should a neonate be treated with ART?

6 weeks

50

Which pts receive ART in pregnancy?

-If newly diagnosed in 1st trimester, & pt does not meet guidelines to start ARV therapy for herself, then defer tx until 14w to decr embryopathy risk. -If pt presents and is already on ARV, then co ntinue tx (d/c teratogenic agents)-Continue ARV tx for duration of pregnancy to decr vertical txmission.-Should start tx by 28w to achieve undetectable VL prior to delivery

51

How common is ART resistance?

8-16%

52

Which women should receive AZT during pregnancy (before labor)?

-Women who present before labor, and not already on ARV tx, should be started on a HAART regimen that includes AZT-If a woman already on ARV tx presents less than 36w, then continue HAART and include AZT, even if resistant

53

Guidelines for selecting an ART regimen in pregnancy

-At least one nucleoside reverse transcriptase inhibitor (NRTI) with high placental transfer (zidovudine/lamivudine/stavudine/tenofovir/abacavir) should be included if possible.-AZT should be part of the regimen in all pregnant women unless contraindicated: antepartum AZT orally 300 mg bid from week 14 until delivery -AZT can cause anemia and neutropenia, so monitor CBC.

54

AZT dosing in labor

Intrapartum infusion of AZT IV 2 mg/kg over the first hour followed by a continuous infusion of 1 mg/kg/hr until delivery.

55

ARV medications/combinations to avoid

Efavirenz, hydroxyurea, amprenavir solution, combinations of AZT with d4T or d4T with ddI.

56

Side effects of AZT

Hemoglobin < 8 g/dLAbsolute neutrophil count < 750 cells/mm3AST or ALT > 5x nlRarely linked to mitochondrial toxicity in neonates

57

Side effects of protease inhibitors

Hyperglycemia (new-onset DM, exacerbation of existing DM, DKA)

58

Side effects of non-nucleoside reverse transcriptase inhibitors

(Nevirapine)RashHepatotoxicityRisk higher if CD4 > 250 cells/mm3Monitor transaminases, esp in first 18w of tx

59

Are there any teratogenic ARV agents?

Efavirenz - increased NTDs in animal studies

60

Antiretroviral tx in pregnancy - recommended agents

NRTI - Zidovudine (AZT, aka Retrovir) + Lamivudine (3TC, aka Epivir)) = CombivirNNRTI - Nevirapine (aka Viramune)PI - Lopinavir/ritonavir (aka Kaletra)

61

Antiretroviral tx in pregnancy - alternate agents

NRTI - Didanosine (ddI, aka Videx), Emtricitabine (aka Emtriva), Stavudine (d4T, aka Zerit), Abacavir (aka Ziagen)[fatal lactic acidosis has occured w/ ddI+D4T, use only if no other alternative]PI - Indinavir (Crixivan, requires boosting with ritonavir); Nelfinavir (Viricept), Atazanavir (Reyataz), Saquinavir (Invirase)

62

Antiretroviral tx in pregnancy - use in special circumstances

NRTI - Tenofovir (Viread, limited studies in preg, bone demineralization w/ chronic use)NNRTI - Efavirenz (Sustiva, CNS defects, avoid in 1st trim)PI - Amprenavir, Fosamprenavir - no studies in human pregnancy

63

Which ARV should be used in HBV+ pts?

Lamivudine, Tenofovir

64

Which uterotonic should be avoided due to the risk for protease inhibitor p450 interaction?

Methergine

65

Vaccines in HIV+ pts

PneumovaxHepatitis BInfluenzaHepatitis A if HCV+TetanusDiptheriaInactivated polio if at riskRubella PP if CD4 > 200Varicella - being evaluated, not currently recommendedBCG - should not be administered

66

Opportunistic infections

Pneumocystis jiroveci pneumoniaToxoplasmic encephalitisDisseminated Mycobacterium avium complexMycobacterium tuberculosisVaricella zoster virusCandidiasisNon-Hodgkin lymphoma

67

PCP pneumonia - indications for prophylaxis and first line drug

CD4 count <14History of AIDS-defining illnessHistory of oropharyngeal candidiasisHistory of PCP pneumonia (secondary prophylaxis)Trimethoprim-sulfamethoxazole(TMP-SMZ) one DS tablet daily

68

Disseminated MAC - indications for prophylaxis and first line tx

CD4 < 50 cells/uLAzithromycin 1200 mg PO/wk

69

Toxoplasmic encephalitis - indications for prophylaxis and first line tx

CD4 < 100 cells/uLSeropositive for T. gondii IgGTMP-SMZ one DS tab daily

70

Mycobacterium tuberculosis - indications for prophylaxis and first line tx

PPD >/= 5mm ORPrior + PPD w/o adequate tx ORContact with person with active TBregardless of PPD statusINH sensitive:INH 300 mg po + pyridoxine 50 mg po daily x 9 mo ORINH 900 mg po + pyridoxine 100 mg po 2x/w x 9 moINH resistant:Rifampin 600 mg po daily ORrifabutin 300 mg po daily x 4 mo

71

Varicella zoster - indications for prophylaxis and first line tx

Varicella nonimmune and exposed tochickenpox or shinglesVaricella Zoster immune globulin—5 vials (1.25 mL each) within 48–96 hours ofexposure

72

Cryptococcus - indications for prophylaxis and first line tx

CD4 < 50/mm3Fluconazole 150 mg PO daily

73

HSV - indications for prophylaxis and first line tx

Recurrent outbreaksAcyclovir 400 mg BID

74

Candidiasis - indications for prophylaxis and first line tx

Recurrent infectionsFluconazole 150 mg PO daily

75

What is the most common serious opportunistic disease in women w/ HIV?

PCP pneumonia

76

What is the second most common serious opportunistic disease in women w/ HIV?

Mycobacterium avium complex