Immunology

Question 1

What type of immunodeficiency is DiGeorge syndrome?

Answer 1

Congenital T-cell

Question 2

What genetic abnormality causes DiGeorge syndrome?

Answer 2

Microdeletion at chromosome 22 - 22q11.2

Question 3

What are the clinical features of DiGeorge syndrome?

Answer 3

CATCH-22

C - cardiac anomalies

A - anomalous face

T - thymus aplasia/hypoplasia

C - cleft palate

H - hypocalcemia (due to hypoparathyroidism)

22 - affected chromosome

Question 4

What is defective in severe combined immunodeficiency?

Answer 4

B and T cell function

Often fatal within the first year of life

Question 5

Which immunodeficiency presents > 4 months after birth?

Answer 5

X-linked agammaglobulinemia

Transplacentally transferred maternal IgG is no longer active

Question 6

What is the triad of Wiskott-Aldrich syndrome?

Answer 6

1. Eczema
2. Bleeding diathesis
3. Recurrent opportunistic infections in the first years of life
   * Impaired T cell function and thrombocytopenia*

Question 7

How is a diagnosis of an allergy made?

Answer 7

1. Demonstration of IgE specific to that allergen e.g., positive skin prick
2. Confirmation that symptoms occur when the patient is exposed to the allergen

Question 8

What is the best test for investigating a suspected food allergy?

Answer 8

Radioallergosorbent test (RAST)

Question 9

What adrenaline dose is given in an Epi-pen Junior?

Answer 9

0.15 mg

Children under 20kg

Question 10

What adrenaline dose is given in an Epi-pen?

Answer 10

0.3 mg

Children and adults > 20kg

Question 11

What is chronic granulomatous disease?

Answer 11

Deficiency of phagocytic superoxide production

Recurrent catalase-positive infections (S. aureus, Nocardia, E. coli, Candida, Klebsiella, Pseudomonas, Aspergillus)

Question 12

An increased rate of febrile convulsions occurs 2 weeks following which vaccination?

Answer 12

MMR

Question 13

Delayed umbilical cord separation (> 3 weeks) raises suspicion of which condition?

Answer 13

Leukocyte adhesion deficiency

Question 14

Which medications are most strongly associated with serum sickness-like reactions?

Answer 14

Amoxicillin

Cefaclor

Question 15

A mother brings in her 1-month-old daughter because she noticed excessive tearing of her right eye. On examination of her right eye she had a large and hazy cornea and an asymmetric red reflex. The most likely condition is:

1. Cataracts
2. Glaucoma
3. Conjunctivitis
4. Retinoblastoma
5. Uveitis

Answer 15

Glaucoma