HIV & Opportunistic Infections

Question 1

HIV is of the retroviridae family and lentivirus genus. HIV1 is primarily found in America, Europe, and Central Africa while HIV2 is more localized to West Africa.

The virus is roughly spherical with 2 positive ssRNA held together by ________. It is enclosed by a conical capsid of viral protein called ____. It has very high genetic variability with a genome consisting of 9 genes and ____, ____, and ____ are most important in making structural proteins for new virus particles

Answer 1

P7 protein

P24

gag; pol; env

Question 2

What part of HIV contains the 3 enzymes required for HIV replication (reverse transcriptase, integrase, and protease)?

Answer 2

Capsid

Question 3

The infectivity of HIV stems from its ability to integrate into __________ and altering cell-mediated immunity

Answer 3

CD4 T-lymphocytes

Question 4

Transmission risks associated with HIV

Answer 4

Receptive anal intercourse (1:100 to 1:30)

Insertive anal intercourse and receptive vaginal intercourse (1:1000)

Insertive vaginal intercourse (1:10,000)

Risk increases with inflamed or ulcerated mucosa

Needlestick with infected blood (1:300)

Sharing IV drug use needles with HIV+ (1:150)

Blood transfusion from HIV+ (95%)

13-40% of children born to HIVinfected mothers without maternal tx or perinatal prophylaxis contract HIV infection

Question 5

T/F: Infectivity of HIV increases with concurrent genital ulcer disease (i.e.,syphilis)

Answer 5

True

Question 6

Which of the following populations has the highest overall percentage of new HIV infections?

A. Sex workers
B. People who inject drugs
C. Gay men and other men who have sex with men
D. Transgender people
E. General population
F. Clients of sex workers

Answer 6

E. General population

Question 7

Opportunistic infections associated with CD4 count <500

Answer 7

Bacterial infections
Tuberculosis
Herpes simplex
Herpes zoster
Vaginal candidiasis
Hairy leukoplakia
Kaposi sarcoma

Question 8

Opportunistic infections associated with CD4 count <200

Answer 8

Pneumocystosis (Pneumocystis jirovecii aka P.carinii)

Toxoplasmosis

Cryptococcosis

Coccidiodomycosis

Cryptosporidiosis

[He also has disseminated histoplasmosis, Kaposi’s sarcoma, and extrapulmonary/miliary TB listed here]

Question 9

Opportunistic infections associated with CD4 count <50

Answer 9

Disseminated mycobacteirum-avium complex (MAC) infection

Histoplasmosis
CMV retinitis
CNS lymphoma

Question 10

In an HIV pt, PE may be entirely normal. Abnormal findings range from completely nonspecific (i.e., generalized LAD) to highly specific for HIV infection. What are the ones that are specific for HIV infection?

Answer 10

Hairy leukoplakia of the tongue

Disseminated Kaposi sarcoma

Cutaneous bacillary angiomatosis

Question 11

Describe diagnostic testing for HIV

Answer 11

Combined immunoassay for HIV Ab with a test for HIV p24 Ag [positive test requires confirmatory testing] —>

HIV-1/2 Ab differentiation immunoassay [positive test confirms dx]

Samples negative on Ab differentiation are tested with HIV-1 nucleic acid amplification test (NAAT) [if positive, acute HIV is diagnosed; if negative, initial test was a false-positive]

Question 12

Nonspecific lab findings seen with HIV infection

Answer 12

Anemia

Leukopenia (particularly lymphopenia) and thrombocytopenia

Elevated ESR

Polyclonal hypergammaglobulinemia

Hypocholesterolemia

Cutaneous anergy

Question 13

Most widely used marker to provide prognostic information and guide therapy decisions in HIV pts

Answer 13

Absolute CD4 lymphocyte count

Should be monitored every 3-6 months in pts taking antiretroviral tx consistently

Question 14

_____ tests assess level of replication and provide useful prognostic info that is independent of the info provided by CD4 counts

Answer 14

HIV viral load

Question 15

Most common opportunistic infection associated with AIDS

Answer 15

Pneumocystis jirovicii

Question 16

Sputum exam using Wright Giemsa stain or direct fluorescence antibody test can determine dx of pneumocystis in 50-80% of cases, and further testing can be done with bronchoalveolar lavage.

How do diffusing capacity of carbon monoxide, high-resolution CT scan, and CD4 count help in the exclusion of pneumocystis pneumonia in an HIV pt?

Answer 16

A normal diffusing capacity of carbon monoxide (DLCO) or a high-resolution CT scan of the chest that demonstrates no interstitial lung disease makes the dx of pneumocystis PNA very unlikely

CD4 count greater than 250 cells/mcL within 2 months prior to evaluation of respiratory symptoms makes a dx of pneumocystis PNA unlikely

Question 17

Most common cause of pulmonary disease in HIV-infected persons

Answer 17

Community acquired PNA (may be bacterial, mycobacterial, or viral)

Question 18

Most common space occupying lesion in HIV, typically occurring at CD4 count <100

Multiple subcortical lesions w/predilection for basal ganglia

Multiple ring-enhancing lesions with surrounding areas of edema

Answer 18

Toxoplasmosis

Question 19

____ can be a cause of considerable morbidity in severely immunocompromised HIV-infected individuals. Major associated problems include retinitis, colitis, esophageal ulceration, encephalitis, and pneumonitis

Answer 19

CMV