-
what is the cause of hereditary angioedema?
C1 esterase inhibitor deficiency
-
in SCID, what is there a deficiency of?
- absent B and T cells
- so look at lymphocyte subsets - see if both absent
-
when does SCID present?
first 6 months of life - unusual infection and severe FTT
-
which infections commonly occur in SCID?
- oral candida
- PCP
- chronic diarrhoea
- ear infections
-
what is the inheritance of SCID?
x-linked
-
what is Rx of SCID?
bone marrow transplantation
-
what is the most common cause of Ig deficiency?
x-linked agammaglobulinaemia: failure of B cell development and Ig production.
-
when does x-linked gamma present?
- first 2yrs life
- severe bacterial infections - sinopulmonary
-
which gene causes x-linked agammaglob?
bruton tyrosine kinase
-
what is ataxia telangiectasia? inheritance?
- auto recessive
- affects cerebellum - ataxia
- get immune system weak - respiratory disorder and cancer
-
what is the gene in ataxia telangiectasia responsible for?
DNA repair gene
-
what is the triad in wiskott-aldrich syndrome?
- immunodeficiency
- thrombocytopenia - so may need splenectomy
- eczema
-
what is the inheritance of wiskott-aldrich syndrome?
x-linked
-
what is curative for wiskott-aldrich syndrome?
BM transplant
-
what causes DiGeorge syndrome - maldevelopment of…
- 5th branchial arch causing heart
- Cardiac
- Abnormal facies
- Thymus aplasia
- Cleft palate
- Hypocalcaemia (due to low PTH)
-
what are the causes of secondary immunodeficiency?
- HIV
- immunosuppression drugs - chemotherapy, steroids,
- cancer
- malnutrition
- nephrotic syndrome
- splenectomy
- bacterial and viral infections
-
which tests are used to assess immune function in children?
- FBC
- lymphocyte subsets
- Ig
- specific Ig
- Neutrophils NBT - chronic granulomatous disease
- adhesion molecules
- complement
- genes
-
which 2 types of inheritance is most primary immunodeficiency?
x-linked or AR
-
what needs to be asked in history of immunodef?
- FH of consanguinity
- unexplained death - boys
-
what are the clinical features in most primary immunodef?
- infections
- protein losing enteropathy
- FTT
-
what are the 3 main arms of Rx of primary immunodef - other than gene therapy!
- antibiotic prophylaxis - PCP co-trimoxazole
- antibiotic therapy when infection happens
- Ig replacement if defective antibody production or function
- BM transplant in severe immunodef
-
which primary immunodef leads to chronic bacterial and fungal infections?
- chronic granulomatous disease
- phagocytic cells fail to produce superoxide after ingestion of microorganisms
- need prophylactic abx and INF gamma
-
what is delayed separation of the umbilical cord a classical features of?
- leucocyte adhesion deficiency
- also get delayed wound healing, chronic skill ulcers, deep seated infection (remember the WBC cant get there!!)
-
which primary immunodef would benefit greatly from prophylactic antibiotics?
chronic granulomatous disease
-
which 1ry immunodef has defect in the bruton tyrosine kinase gene?
x linked agammaglobulinaemia
-
how may complement deficiency present?
recurrent meningitis
-
with a viral infection - which cell has a rapid response?
natural killer cell response
-
which infections do cytotoxic T cells attack?
viral infections
-
what are the main causes of secondary immunodeficiency in children?
- immunosuppressive therapy eg cytotoxic drugs and steroids
- HIV
- measles
-
what is the consequences of cytotoxic drugs?
- eg in ALL
- chemo is very immunosuppressive as BM suppression and neutropenia
- if febrile neutropenia then at risk of potentially fatal bacterial and fungal infections
-
why would a child be taking high dose steroids?
nephrotic syndrome
-
what are potential problems with taking steroids?
disseminated chickenpox
-
what are children who have had organ transplants at risk of?
CMV infection
-
what are the ways of HIV transmission to children?v
- vertical transmission
- blood products
-
what are the 3 main routes of vertical transmission?
- intrauterine
- intrapartum
- breast feeding
-
when do children have their mothers HIV antibodies until?
15-18 months, then disappear
-
how is HIV diagnosed in children - what test?
- HIV viral culture: gold standard, but not widely available
- PCR for viral genome
-
what is the incubation of HIV in children cf to adults?
shorter in perinatally infected children
-
what % of the CD4 count do you need for moderate immunosupp?
15-25%
-
what % of CD4 count gives severe immunosupp?
<15%
-
what are symptoms of mild HIV?
- lymphadenopathy
- hepatosplenomegaly
- parotitis
-
what are symptoms of moderate HIV?
- severe bacterial infection
- chronic diarrhoea
- candida
- lymphocytic interstitial pneumonitis
-
what are symptoms of severe HIV ie AIDS?
- wasting as FTT
- opportunistic infection eg PCP
- encephalopathy
- severe bacterial infection
- malignancy-rare
-
what are the neurological complications of AIDS?
- encephalopathy
- seizures
- motor defect
-
what are the GI complication of AIDS?
- anorexia
- nausea
- diarrhoea
- wt loss
-
what are the skin condition in AIDS
kaposis sarcoma
-
what is management of paediatric HIV?
- co-trimoxazole PCP prophylaxis
- primary immunisation course should be given
- BCG not recommended
- defer MMR if severely immunosupp
- antiretroviral Rx if symptomatic or CD4<15% - RT inhibitor and protease inhibitors
-
how is paediatric HIV prevented?
- antenatal screening for HIV
- zidovudine during pregnancy, delivery and to neonate for 6 weeks
- reduces vertical transmission of HIV1
- C/S unless low viral load can have vaginal delivery
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