Allergic and Immunologic Disorders Case

An 8-year-old boy is new to your practice.

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Nov 20, 2019
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You note as he enters the room with his mother that he seems somewhat “off balance” to which his mom replies that she had noted changes in his gait for the last 3 to 4 years, but thought he was just “clumsy.” You are reviewing his medical history and find that he has been treated for recurrent otitis media and sinusitis despite having three sets of tympanostomy tubes since age 2. On examination, you note several superficial blood vessels apparent in the eyes and on the pinna of the ear. Concerned with the history and examination findings, you order a CBC that demonstrates profound lymphopenia as well as quantitative immunoglobulin levels and vaccine titers to pneumococcus and tetanus, all of which are low.

What diagnosis are you most concerned with based on the constellation of symptoms?

A. Neuroblastoma.

B. Chédiak-Higashi syndrome.

C. WHIM syndrome.

D. Ataxia-telangiectasia.

E. Hyper-IgM syndrome.




The correct answer is “D.” Ataxia-telangiectasia (AT) is caused by a defect in ATM repair gene, which leads to a combined B- and T-cell defect. Low immunoglobulin levels and lymphopenia will be noted on screening labs. Progressive cerebellar ataxia and neuron loss occur with age. Ataxia is the earliest clinical manifestation, with initial symptoms beginning around 2 to 3 years of age. Telangiectasias of the bulbar conjunctiva and skin typically manifest with disease progression. AT is inherited in an autosomal recessive pattern. Serum alpha fetoprotein is often elevated in AT. WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome and Chédiak-Higashi syndrome are associated with neutropenia. Hyper-IgM syndrome is characterized by elevated IgM, low IgG and IgA, and decreased T-cell response to antigens. Affected individuals have recurrent infections similar to other conditions with combined impaired B- and T-cell function.


Sources:

Question & Explanation: Peterson AR, Wood KE. Pediatrics Examination and Board Review. New York, NY: McGraw-Hill Education; 2017.

Photo: Prose NS, Kristal L. Weinberg's Color Atlas of Pediatric Dermatology, 5e; 2017


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Leah Carton

Editorial Coordinator , McGraw-Hill Education

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