Immunodeficiency in a child (incl. HIV) Flashcards

1
Q

Define HIV.

A

Virus that infects and disables the host’s CD4 T cells.

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2
Q

Explain the aetiology of HIV.

A

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.

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3
Q

What are differential diagnoses for HIV?

A

Immunodeficiency (DiGeorge syndrome, chronic granulomatous disease).

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4
Q

What are coinfections with HIV?

A

Tuberculosis

Hepatitis B/C and sexually transmitted diseases.

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5
Q

Summarise the epidemiology of HIV.

A

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.

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6
Q

What are general signs and symptoms of HIV?

A

Failure to thrive, developmental delay, chronic diarrhoea, lymphadenopathy, bilateral non-tender parotitis, hepatosplenomegaly.

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7
Q

What infections can be a sign of HIV?

A
  • 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.
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8
Q

What neoplasm is associated with HIV?

A

B-cell lymphoproliferative disease

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9
Q

What are appropriate investigations for HIV?

A

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.

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10
Q

What is the management for HIV?

A

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).

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11
Q

What are complications associated with HIV?

A

Drug side effects, e.g. myelosuppression with zidovudine. Poor compliance rapidly leads to drug resistance. Opportunistic infections with progression of disease.

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12
Q

What is the prognosis of HIV?

A

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.

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