Snapshot A 2-month-old baby boy is brought in for an urgent visit to the pediatrician. He has had several ear infections in his short lifetime and now seems to be struggling with a cold. On physical exam, his tongue is noted to be coated with white film. His scalp and face are covered with a flaky dandruff-like substance. Immediately concerned, his pediatrician orders a chest radiograph, which shows absence of thymic shadow. Flow cytometry is ordered. Introduction Combined B- and T-cell disorder causing immunodeficiency Life-threatening disease of recurrent infections Pathogenesis multiple variants found most common is X-linked defective common gamma chain found in IL-2R, IL-4R, and IL-7R defective T-cell activation autosomal recessive adenosine deaminase deficiency 2nd most common ↑ deoxyadenosine, which is toxic to lymphocytes ↓ DNA synthesis autosomal recessive JAK3 deficiency B-cells decreased immunoglobulin production T-cells markedly decreased T-cells Presentation Symptoms symptoms present < 3 months of age failure to thrive recurrent bacterial, viral, fungal, and protozoal infections chronic diarrhea Physical exam may see thrush in mouth and diaper area eczematous dermatitis erythroderma (> 90% body surface area involvement) severe seborrheic dermatitis diffuse alopecia absent lymphatic tissue, including tonsils and thymus Evaluation Diagnosis often delayed due to maternal IgG protecting baby in first few months of life ↓ Lymphocyte count (< 3000/μL) Chest radiography with no thymic shadow Flow cytometry absent T-cells abnormal function of B-cells Differential Diagnosis Hypogammaglobulinemia DiGeorge syndrome Hyper-IgM syndrome Ataxia-telangiectasia Treatment Bone marrow transplant life-saving treatment no concerns for allograft rejection Gene therapy Prognosis, Prevention, and Complications Prognosis without intervention, death by 2 years patients < 6 months of age who receive transplant have the best outcomes Complications severe infection death
QUESTIONS 1 of 7 1 2 3 4 5 6 7 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (M1.IM.15.74) A 4-month-old boy is brought to the pediatrician by his foster mother. She has no knowledge of his birth history but states that, for the past 3 months, he has had multiple viral and bacterial infections in addition to repeated bouts of diarrhea. On exam, the pediatrician observes the findings demonstrated in Figure A. The pediatrician tells the foster mother he is concerned the child may have an immunodeficiency. Levels of which of the following would be most likely to be reduced in this patient? QID: 106688 FIGURES: A Type & Select Correct Answer 1 Inosine 37% (85/229) 2 Adenosine 39% (90/229) 3 Cytosine 5% (12/229) 4 Thymine 14% (31/229) 5 Uracil 3% (8/229) M 1 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (M1.IM.13.39) A 3-year-old Cuban-American male has a history of recurrent Pseudomonas and Candida infections. Laboratory analysis reveals no electrolyte abnormalities. Examination of his serum shows decreased levels of IgG and CT scan reveals the absence of a thymus. The child likely has: QID: 100460 Type & Select Correct Answer 1 Severe combined immunodeficiency syndrome 55% (37/67) 2 X-linked agammaglobinemia 6% (4/67) 3 DiGeorge syndrome 36% (24/67) 4 Isolated IgA deficiency 0% (0/67) 5 Common variable immunodeficiency 0% (0/67) M 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Review Tested Concept Review Full Topic (M1.IM.13.5) A 6-year-old child presents for evaluation of a medical condition associated with recurrent infections. After reviewing all of the medical history, gene therapy is offered to treat a deficiency in adenosine deaminase (ADA). ADA deficiency is the most common autosomal recessive mutation in which of the following diseases? QID: 100426 Type & Select Correct Answer 1 DiGeorge Syndrome 5% (5/92) 2 Severe Combined Immunodeficiency 78% (72/92) 3 Hyper-IgM Syndrome 0% (0/92) 4 Wiskott-Aldrich Syndrome 8% (7/92) 5 Bruton's Agammaglobulinemia 8% (7/92) M 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic (M1.IM.12.40) A 2-year-old Caucasian male presents with recurrent diaper rash and oral thrush. He has also experienced recurrent episodes of otitis media from repeat Streptoccous pneumoniae. He notably has reduced T and B cell counts. What disease is the child suffering from? QID: 100461 Type & Select Correct Answer 1 X-linked agammaglobulinemia 20% (63/315) 2 Isolated IgA deficiency 7% (21/315) 3 Severe combined immunodeficiency 61% (193/315) 4 DiGeorge syndrome 7% (22/315) 5 MHC class II deficiency 2% (7/315) M 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic
All Videos (0) Immunology | Severe Combined Immunodeficiency Disorder (SCID) Immunology - Severe Combined Immunodeficiency Disorder (SCID) Listen Now 13:21 min 8/27/2021 6 plays 5.0 (1)