WHAT IS THE BEST INITIAL TEST FOR WORK-UP FOR IMMUNODEFICIENCY? CAN YOU ANSWER IT?

MCQ#01

Of the following options, the best initial test for a workup for immunodeficiency is:

A. Serum levels of IgG, IgM, IgA, IgE

B. A complete blood count with differential

C. Peripheral T-cell phenotyping

D. Erythrocyte sedimentation rate

E. Post-immunization immunoglobulin levels

MCQ#02

A 5-month-old child is brought to your office for evaluation of failure to thrive. His mother reports that he has been suffering from constant diarrhea and failure to gain weight. On exam you note that the child is in the 50% percentile for a 1-month-old. Physical exam reveals diffuse erythroderma, a distended, tympanitic abdomen, and a palpable liver and spleen.

In addition to lymphopenia, what other abnormality would you expect to find on assessment of a complete blood count?

A. Macrocytosis

B. Small platelets

C. Neutrophilia

D. Basophilic stippling

E. Eosinophilia

MCQ#03

A 3-year-old boy returns to your office with his sixth upper respiratory infection this year. 

Which of the following factors would increase your index of suspicion for an underlying immunodeficiency?

A. The child is in daycare 4 days per week.

B. The child’s tonsils are grossly enlarged

C. He was hospitalized 3 times last year for infections

D. His thymic shadow is visualized on chest radiograph

E. He is maintaining steady growth at the tenth percentile for height and weight.

MCQ#04

A 6-month-old boy is brought to your office for evaluation of failure to thrive and persistent eczema. The child has had several upper respiratory infections and has been hospitalized for pneumonia twice in the last 2 months. He has not gained weight since the age of 2 months despite adequate intake, although his mother has made him switch from cow’s milk based- to soy-based formula in the hope of improving his severe eczema. Physical exam reveals an irritable child with an extensive eczematous rash on his trunk and legs. He has moderate hepatosplenomegaly and a few petechiae on his legs.

The most likely finding that might be seen on a complete blood count and smear would be which of the following?

A. Low numbers of neutrophils

B. Thrombophilia

C. Microcytosis

D. Low platelet volumes

E. Lymphoblasts

MCQ#05

Patients with hyper IgE syndrome, or Job syndrome, can have infections resulting in severe tissue damage without features of fever, localized erythema, or warmth. 

The immune defect thought to be responsible for this abnormality is which of the following?

A. Elevated IgE levels

B. Defective neutrophil chemotaxis

C. Impaired intracellular killing of organisms

D. Eosinophilia

E. Abnormal antibody cross-linking

ANSWERS TOMORROW 3/9/2019