Immunodeficiency in a child (incl. HIV) Flashcards
Define HIV.
Virus that infects and disables the host’s CD4 T cells.
Explain the aetiology of HIV.
Vertical transmission (>75%): In utero, perinatally or via breastfeeding.
Sexual transmission: Abuse in children, intercourse in adolescents.
IV drug abuse: Rare in children.
Virus enters CD4 lymphocytes by binding with CD4 and a chemokine receptor, using its glycoprotein receptor (gp120). Viral reverse transcriptase converts RNA to DNA, which is incorporated into the host genome.
What are differential diagnoses for HIV?
Immunodeficiency (DiGeorge syndrome, chronic granulomatous disease).
What are coinfections with HIV?
Tuberculosis
Hepatitis B/C and sexually transmitted diseases.
Summarise the epidemiology of HIV.
2,000,000 children worldwide were suspected to be infected in 2007. 1,800,000 of those children live in sub-Saharan Africa. Higher rates of prevalence within children from ethnic minority groups.
What are general signs and symptoms of HIV?
Failure to thrive, developmental delay, chronic diarrhoea, lymphadenopathy, bilateral non-tender parotitis, hepatosplenomegaly.
What infections can be a sign of HIV?
- Recurrent bacterial infections and viral infections
- Opportunistic infections (PCP is an AIDS-defining disease)
- Oral candidiasis: white/yellow plaques and loss of tongue papillae
- Herpes simplex: herpes labialis, gingivostomatitis, oesophagitis or chronic skin vesicles
- VZV: recurrent/persistent/severe infection
- Human papillomavirus: flat warts covering large areas of the body
- Fungal infections: tinea capitis resistant to treatment.
What neoplasm is associated with HIV?
B-cell lymphoproliferative disease
What are appropriate investigations for HIV?
Neonatal bloods: HIV serology and DNA for PCR are taken at birth before antiretroviral prophylaxis is commenced. Repeat bloods are taken at 6 weeks and 3 months and serology is repeated until the child is >18 months when maternal antibodies will have disappeared.
Confirmatory tests: HIV RNA PCR, CD4 count, baseline resistance screen.
Endoscopy: If oesophageal candidiasis is suspected. Screen for other diseases: TB (Mantoux), hepatitis B/C, syphilis and toxoplasmosis.
What is the management for HIV?
Prevention: Without preventive measures 25–40% of children will acquire vertical transmission of HIV.
- All pregnant women are offered antenatal screening for HIV and hepatitis B/C.
- Mothers with HIV should not breastfeed their child (UK guidelines). Risk decreases from 25–40% to 15% when breastfeeding is avoided.
- Reduce maternal viral load with antiretroviral drugs antenatally, perinatally and post-natally; reduces transmission rate to 5%.
- Elective caesarean section to avoid contact with the birth canal; reduces transmission rate to 1% (less with low maternal viral load).
- Empirical treatment with antiretroviral medication (usually zidovudine) post-natally.
Prophylaxis: Co-trimoxazole against PCP, routine immunisation schedule but no live vaccines (except MMR).
What are complications associated with HIV?
Drug side effects, e.g. myelosuppression with zidovudine. Poor compliance rapidly leads to drug resistance. Opportunistic infections with progression of disease.
What is the prognosis of HIV?
Children with untreated HIV infection progress rapidly and approximately 25% develop AIDS in the first year of life. Mortality is >50% by 2 years of age in poorly resourced areas.
