HIV Clinical Monitoring and Progression

Question 1

How is HIV diagnosed?

Answer 1

Combined Ab/Ag test:

• looks for anti-HIV Ab-and-HIVp24 Ag (detectable before Ab)
• if positive -> Ab differentiation
• if negative -> no HIV or too early to detect

Ab differentiation:

• specifically idenitifies HIV-1, HIV-2, or mixed infections based on Ab
• if positive -> HIV diagnosis confirmed
• if negative -> NAAT

NAAT (nucleic acid amplification):

• if positive -> acute HIV (too early for other tests to detect)
• if negative -> no HIV/combined Ab/Ag was false positive

Question 2

What tests are used to assess the progression and current state of HIV?

Answer 2

CD4 count:

• prognostic
• represents immune function; lower count -> higher risk of serious infections

Viral load:

• prognostic
• represents viral replication
• higher viral load -> more infectious
• increasing viral load = progression of disease (failure of treatment?)

Question 3

What conditions can present with a CD4 count >300 in HIV?

Answer 3

-reactivation of tuberculosis (pulmonary) and herpes zoster (shingles) infections

• HIV fatigue syndrome
• oral/vaginal candidiasis
• pneumococcal pneumonia _{(normal pneumonia but in people who nomrally would not be considered at risk)}

Question 4

What conditions can present with a CD4 count of 200-300 in HIV?

Answer 4

• oral hairy leukoplakia (EBV; non-scrapable plaques on side of tongue)
• thrush (scrapable w/ pseudohyphae, w/o esophageal involvement)
• worsening fatigue syndrome (fever, weight loss, diarrhea)

Question 5

What conditions can present with a CD4 count of 100-200 in HIV?

Answer 5

These are AIDS defining

• Pneumocystis jiovecii pneumonia
• disseminated histoplasmosis

Worsening reactivations:

• Kaposi sarcoma (HHV-8; skin/mucosal lesions initially facial/oral)
• extrapulmonary/miliary TB
• progressive multifocal leukoencephalopathy/PML (JC virus; non-enhancing, demylination lesions in white matter)
• lymphoma (EBV -> Burkitt (NHL) or HL)

Question 6

What conditions can present with a CD4 count of 50-100 in HIV?

Answer 6

• CNS toxoplasmosis (multiple ring-enhancing lesions)
• esophageal/pulmonary candidiasis
• cryptococcal meningitis

Question 7

What conditions can present with a CD4 count of <50 in HIV?

Answer 7

• mycobacterium-avium complex/MAC
• primary CNS lymphoma (EBV; diffuse large B-cell)
• cytomegalovirus

Question 8

When is AIDS diagnosed?

Answer 8

CD4 count <200

-or-

pressence of AIDS-defining illness

Question 9

What are AIDS-defining illnesses?

Answer 9

• multiple/recurrent bacterial infections (ie. CAP)
• pneumocystis jirovecii
• cancer (Kaposi sarcoma or lymphomas)
• CMV
• histoplasmosis
• tuberculosis (any site)
• coccidioidomycosis
• cryptococcosis

Question 10

What is the most common AIDS-defining illness?

Answer 10

Pneumocystis jirovecii/pneumocystis pneumonia

Question 11

What are identifying characteristics of Pneumocystis jirovecii?

Answer 11

• “ground glass” appearing
• apical infiltrates -> apical cysts/pneumoatoceles

Question 12

What AIDS-defining conditions appear with ring-enhancing brain lesions?

What differentiates them?

Answer 12

Toxoplasmosis:

-multiple lesions

Primary CNS lymphoma:

-single lesion

Question 13

What symptoms are associated with CMV?

Which is most common?

Answer 13

CREEP

• colitis
• retinitis (most common)
• esophageal ulceration
• encephalitis
• pneumonitis

Question 14

What prophylacitic treatments should be given in HIV/AIDS and when?

Answer 14

Bactrim (Pneumocystis jirovecii):

-CD4 <200 or after oropharyngeal candidiasis

Vaccinations:

• hepatitis A/B (all)
• Influenza (yearly)
• Strep. pneumoniae (all)

-HPV (all between 13-26)