HIV exposure and infection in children — branching viva

Branching structured-oral viva on paediatric HIV: mother-to-child transmission and its prevention (PMTCT, Option B+), the distinction between exposure and infection (maternal IgG versus infant viraemia), HIV DNA/RNA PCR diagnosis under 18 months, rapid infant progression and the survival benefit of early ART, cotrimoxazole prophylaxis, Pneumocystis pneumonia, and adolescent transition.

branching clinical structured oral4 min readVerification in progress

Prompt

You are the general paediatric registrar in the emergency department. A 4-month-old infant born to a mother known to be HIV-positive but disengaged from care presents with three days of worsening cough, marked tachypnoea and an oxygen saturation of 86% in air; the chest X-ray shows diffuse bilateral interstitial infiltrates. The infant has never had an HIV PCR and is on no prophylaxis. The examiner asks you to take the candidate through the diagnosis, immediate management and definitive care of this presentation, and the prevention of the next case.

Opening question

Examiner: Take me through this infant. What is the most likely diagnosis, and what is your immediate frame? [8]

Candidate: The most likely diagnosis is Pneumocystis jirovecii pneumonia in an HIV-exposed, unprophylaxed infant of an unsuppressed mother. The age — four months — the hypoxia out of proportion to auscultatory findings, and the diffuse bilateral interstitial infiltrates are the classic picture. My frame is two-layered: keep this infant alive now, and then confirm the HIV status and treat the underlying immunodeficiency. I would give oxygen, admit, start empiric high-dose co-trimoxazole with a corticosteroid for moderate–severe disease, and pursue the diagnosis. [8] [1]

Examiner: Why Pneumocystis specifically? [8]

Candidate: Because PCP is the opportunistic pneumonia of infant HIV, classically presenting between three and six months in an infected, unprophylaxed infant. The hypoxia is disproportionate to the chest findings, the X-ray shows diffuse interstitial infiltrates, and the infant of an unsuppressed, disengaged mother is exactly the child who acquires infection and is missed. The onset is subacute over days but can decompensate over hours, so I treat empirically while confirming. [8]

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References5Show ledger

[1]Violari A; Cotton MF; Gibb DM; Babiker AG; et al Early antiretroviral therapy and mortality among HIV-infected infants. N Engl J Med, 2008.PMID 19020325
[4]Newell ML; Coovadia H; Cortina-Borja M; Rollins N; et al Mortality of infected and uninfected infants born to HIV-infected mothers in Africa: a pooled analysis. Lancet, 2004.PMID 15464184
[5]Foster C; Pace M; Kaye S; Hopkins E; et al Paediatric European Network for Treatment of AIDS Treatment Guideline 2016 update: antiretroviral therapy recommended for all children living with HIV. HIV Med, 2017.PMID 27385585
[7]Havens PL; Mofenson LM; American Academy of Pediatrics Committee on Pediatric AIDS Evaluation and management of the infant exposed to HIV-1 in the United States. Pediatrics, 2009.PMID 19117880
[8]Mofenson LM; Brady MT; Danner SP; Dominguez KL; et al Guidelines for the Prevention and Treatment of Opportunistic Infections among HIV-exposed and HIV-infected children. MMWR Recomm Rep, 2009.PMID 19730409