questions 2

Chediak-Higashi Syndrome

Topic updated on 10/08/17 7:40pm

  • 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.
  • 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
  • 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
  • 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
  • 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


Qbank (1 Questions)

(M1.IM.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? Topic Review Topic
FIGURES: A   B        

1. Autosomal dominant
2. X-linked recessive
3. X-linked dominant
4. Autosomal recessive
5. Maternal inheritance

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