Pocket Pediatrics: The Massachusetts General Hospital for Children Handbook of Pediatrics (Pocket Notebook Series), 2 Ed.

HIV

Etiology (AAP Redbook 2009)

• HIV-1 most common in US, HIV-2 more common in West Africa

• Retrovirus infection, which infects and depletes CD4 cells over time, leading to severe immunocompromise (AIDS) and opportunistic infections (OIs)

Epidemiology

• Preadolescent infections: 100–200 infant infections/year in US

• Adolescent infections on the rise: In 2005, ∼14% of newly diagnosed HIV-1 infections in US were among 13–24 yo, most asymptomatic and unaware of HIV status (RF: Minority, MSM)

Transmission (JAMA 2000;283:1175)

• Vertical transmission: In utero (↑ risk w/ ↑ maternal viral load): 5–10% transmission

• During delivery (↑ risk w/ vaginal delivery): 10–20% transmission

• Breast-feeding (↑ risk w/ mixed formula + breast milk): 5–20% transmission

• Horizontal transmission: Sexual contact, injection drug use, blood transfusions

Clinical Manifestations (AAP Redbook 2009)

• Early manifestations: Unexplained fevers, generalized LAD, HSM, FTT, persistent/recurrent oral & diaper candidiasis, recurrent diarrhea, parotitis, hepatitis, central nervous system (CNS) disease, recurrent invasive bacterial infections, and other opportunistic infections (e.g., viral and fungal)

• Median age until sx after perinatal infxn is 12–18 mo, some asymptomatic >5 yr

• Historically, 15–20% mortality in perinatally infected pts by 4 yo if no Rx available

• Newly HIV-infected adolescents and adults may be asymp for yrs (latent infxn) until they progress to severe immunocompromise

Diagnostic Studies (N Engl J Med 1988;319:961; MMWR 1990;39:380)

• HIV ELISA: 1st-line screening test (99+% sensitivity and specificity)

• Western blot: Confirmatory test (99+% sensitivity and specificity)

• HIV-1 PCR: (99% sensitivity, 98% specificity)

• Used to dx acute HIV before HIV ELISA turns + (usually w/i 3 mo)

• CD4 absolute count predicts risk for opportunistic infections

• CD4% more reliable in young children (less variability between tests)

• Indications to initiate antiretroviral therapy (www.aidsinfo.nih.gov); initiation of therapy depends on a combination of factors including the age of the child, and virologic, immunologic, and clinical criteria

Management

• Typical ARV treatment regimens (www.aidsinfo.nih.gov)

• In general, combinations of at least 3 drugs are recommended

• 1st-line Rx: 2 NRTIs PLUS 1 PI or NNRT (≥42 wk & postnatal ≥14 d of age: Lopinavir/ritonavir; ≥6 yr: Atazanavir/ritonavir)

• 2nd-line Rx: 2 NRTIs and 1 NNRTI

• Not generally recommended: 3 NRTIs (AZT, 3TC, abacavir)

• Goal to suppress viral load to undetectable levels and allow restoration CD4

• Recommend to screen all Rx-naïve pts or pts failing ARV Rx for viral resistance

• All std vaccinations recommended (including MMR), except varicella 2/2 risk of systemic disease (MMWR Recomm Rep 2006;55:Q1 PMID: 17136024)

Opportunistic infections & prophy (USPS/IDSA Guidelines for OI Prevention 2002)

Care of Infants Born to HIV Positive Mothers (http://AIDSinfo.nih.gov)

• Any +HIV, RNA, PCR, or HIV ELISA should be repeated promptly and ID notified

• HIV-infected patients should be immunized with age-appropriate inactivated vaccines as well as annual influenza vaccine

• Unless severely immunosuppressed, MMR is appropriate for children >1 yo. Infants with HIV should not receive MMR