Diagnosing vertically acquired HIV-1
Don't use standard tests (placentally transferred IgG lasts for 18 months). Virus culture & PCR are reliable, and more sensitive than finding antigen in blood. HIV-specific IgA doesn't cross the placenta, but only occurs in 50% of infected infants <6 months old. Discuss with lab. Aim to diagnose 95% of infected infants before the age of 1 month. Monitoring CD4 counts helps in staging HIV. The all clear can only be given if all tests are negative at 6 months.
Consider HIV in children with
PUO; lymphadenopathy; hepatosplenomegaly; persistent diarrhoea; parotid enlargement; shingles; rife molluscum; thrombocytopenia; recurrent slow-to-clear infections; failure to thrive; clubbing, unexplained organ disease;220 or known TB; pneumocystosis; toxoplasmosis; cryptococcosis; histoplasmosis; CMV; or LIP (below).
Lymphoid interstitial pneumonitis (LIP)
Signs: tachypnoea; hypoxia; clubbing; diffuse reticulonodular infiltrates on CXR; bilateral hilar lymphadenopathy. It is not an AIDS-defining illness. It is 5-fold less serious than pneumocystosis.
Prognosis
By 3yrs old, up to half with early-onset opportunistic infection have died, vs 3% of those with no such infection. Children with slow progression of HIV have persistent neutralizing antibodies. Transplacental passage of maternal neutralizing antibody may also have a role.
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