Immunodeficiency

Question 1

What causes primary immunodeficiency, when does it occur and why?

Answer 1

1. Due to an immunological problem (usually genetic)

2. 6 months old - maternal antibodies are still circulating in the child’s blood up to this age.

Question 2

What are the causes of secondary immunodeficiency?

Answer 2

Myeloma, chronic lymphoblastic leukaemia, nephrotic syndrome, protein losing enteropathy, AIDS, immunosuppressive medications (chemo).

Question 3

What should you suspect in severe, persistent, unusual, or recurrent infections?

Answer 3

Immunodeficiency

Question 4

What are the initial tests you should carry out if suspecting immunodeficiency?

Answer 4

FBC (lymphocyte and neutrophil count), IgM/IgG/IgA, C3 and C4.

Question 5

Of these conditions, which are B-cell mediated, which are neutrophil mediated, and which are combined B- and T-cell mediated?

1. Common variable immune deficiency
2. X-linked agammaglobulinemia
3. Severe combined immune deficiency
4. Chronic granulomatous disease

Answer 5

1. B-cell
2. B-cell
3. Combined B & T cell
4. Neutrophil

Question 6

What is this a presentation of?
Early adulthood, IgG deficiency, B and T cells normal, inability to produce antibodies to infection/vaccination, recurrent pulmonary and GI infections, clubbing and lung crackles.

Answer 6

Common variable immune deficiency

Question 7

How is common variable immune deficiency investigated and treated?

Answer 7

1. IgG reduced, pneumococcal and haemophilus antibodies not present.
2. IV immunoglobulins then switch to SC Igs

Question 8

What is this a presentation of?
Recurrent subcutaneous swelling (angioedema) and submucosal swelling (abdominal pain), laryngeal oedema, autosomal dominant disorder.

Answer 8

C1-esterase inhibitor deficiency/hereditary angioedema

Question 9

How is C1-esterase inhibitor deficiency/hereditary angioedema diagnosed and treated?

Answer 9

1. Family history, relationship to allergens, no urticaria, low C4, normal C3, low C1 inhibitor levels.
2. Will not be responsive to anaphylaxis treatment, FFP if diagnosis unclear, C1-esterase inhibitor replacement for established cases.

Question 10

What is this describing?
3 months to 3 years old, recurrent bacterial infections, x linked recessive disorder, defect in Bruton’s tyrosine kinase is required for B-cell maturation.

Answer 10

X-linked agammaglobulinemia

Question 11

How is X-linked agammaglobulinemia investigated and treated?

Answer 11

1. Absence of B-cells, very low Igs, normal T-cells.

2. IV Igs

Question 12

What is this a presentation of?
1 to 3 months old, paediatric emergency, failure to thrive, diarrhoea, CMV and VZV infections, PCP and candidiasis, absent adaptive immunity.

Answer 12

Severe combined immune deficiency

Question 13

How is severe combined immune deficiency investigated and managed?

Answer 13

1. Low B and T cells, low Igs

2. Specialist, treat infections, no live vaccines, bone marrow transplant.

Question 14

What is this a presentation of and how is it treated?

Recurrent pneumonia and abscesses, negative nitroblue-terazolium test.

Answer 14

1. Chronic granulomatous disease

2. Prophylaxis antibiotics and IFNy

Question 15

What is this describing?
Deletion of long arm of chromosome 22, absence of thymus and parathyroid glands. T-cell deficiency, hypocalcaemia, hypoparathyroidism. Cleft palate, heart abnormalities, facial dysmorphism.

Answer 15

DiGeorge’s syndrome