Snapshot A 3-year-old boy is brought to his pediatrician with scraped knees. He had been playing and slipped, scraping his knees on the asphalt. His knees are severely infected, with visible pus. He has a history of bleeding gums and easy bruisability. On physical exam, he is febrile, his retina is noted to be pale, and his hair is very blonde. In fact, some parts of his hair are noted to be silver. He is started on broad-spectrum antibiotics. Introduction Primary immunodeficiency from problems with phagocytosis Genetics autosomal recessive defect in lysosomal trafficking regulator gene LYST Pathogenesis microtubule dysfunction with failure of phagolysosome formation defective secretions defective melanization of melanosomes Symptoms arise in childhood Presentation Symptoms recurrent pyogenic infections, especially of the skin and soft tissue Staphylococcus spp. Streptococcus spp. dermatologic symptoms partial albinism hypopigmentation of skin, eyes, and hair photosensitivity infiltrative lymphohistiocytosis neurological symptoms progressive neurodegeneration peripheral neuropathy pancytopenia easy bruising recurrent infections bleeding Evaluation Diagnosis with light microscopy of peripheral blood smear eosinophilic peroxidase-positive giant granules in neutrophils and platelets Bone marrow smear giant lysosomes in leukocyte precursor cells CBC showing pancytopenia Mild coagulation defects prolonged bleeding time Differential Diagnosis Leukocyte adhesion deficiency Hyper IgM syndrome Treatment Early treatment is important Bone marrow transplant Treat infections as needed Prognosis, Prevention, and Complications Prognosis fatal in childhood, usually before age 10 mortality due to lymphoproliferative syndrome if the affected individual lives to adulthood, progressive neurologic dysfunction is a dominant feature Complications 50-85% develop accelerated phase called hemophagocytic lymphohistiocytosis
QUESTIONS 1 of 3 1 2 3 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 (M1.IM.15.74) A 13-year-old boy presents to his pediatrician for a routine visit. He states that he has been in good health with the exception of repeated staphylococcal infections despite adequate treatment. On exam, the pediatrician observes the findings demonstrated in Figure A, as well as nystagmus. The pediatrician subsequently order a peripheral blood smear which is demonstrated in Figure B. Which of the following is the most likely mode of inheritance of this patient's condition? Tested Concept QID: 106680 FIGURES: A B Type & Select Correct Answer 1 Autosomal dominant 9% (18/196) 2 X-linked recessive 29% (56/196) 3 X-linked dominant 3% (6/196) 4 Autosomal recessive 57% (111/196) 5 Maternal inheritance 1% (1/196) M 2 Question Complexity A Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review tested concept