• An 8-year-old boy is brought to his pediatrician for easy bruising. On physical exam, he is found with petechiae and purpura in multiple areas over his body, as well as bruises over his arms. Eczematous patches are also found on his flexural surfaces. Laboratory results reveal thrombocytopenia to 30,000/mm3. Further questioning reveals a past medical history of multiple hospital stays due to pneumonia and otitis media infections as well as recurrent epistaxis.
  • Primary immunodeficiency disorder of B and T cells
  • Pathogenesis
    • mutation in WAS gene encoding Wiskott-Aldrich syndrome protein (WASp)
      • impaired actin cytoskeleton
      • results in defective T cell signalling and interactions with APCs
      • also impairs phagocytosis and chemotaxis
    • loss of cellular and humoral response
  • Genetics
    • X-linked recessive
  • To remember (WATER)
    • Wiskott
    • Aldrich
    • Thrombocytopenic purpura
    • Eczema
    • Recurrent infections
  • Symptoms/physical exam
    • recurrent bacterial, viral, fungal infections
      • frequency increases with age
      • bacterial agents: Streptococcus pneumonia, Haemophilus influenza, Neisseria meningitides
      • viral agents: varicella and CMV
      • fungal infections: Candida albicans
    • thrombocytopenia
      • recurrent bleeding, especially in first days of life
        • petechiae
        • purpura
        • easy bruising
        • hematemesis
        • epistaxis
        • hematuria
    • chronic eczema
    • hepatosplenomegaly common
  • Serologies
    • ↓ number of T and B cells
    • ↓ to normal IgG, IgM
    • ↑ IgE, IgA
  • Labs
    • thrombocytopenia
      • usually 20,000/mm3 - 50,000/mm3
  • Gene sequence analysis of WAS essential to confirm diagnosis
Differential Diagnosis
  • Severe combined immunodeficiency
  • Hyper IgE syndrome (also with eczema)
  • Atopic dermatitis
  • Antibiotics
  • IVIG
  • Hematopoietic stem cell transplantation
    • only curative treatment
Prognosis, Prevention, and Complications
  • Prognosis
    • reduced life expectancy (see complications below)
    • bleeding is main cause of death
  • Complications
    • increased risk of
      • autoimmune diseases
      • malignancies (lymphomas, leukemias), usually fatal
      • infections
    • complications may lead to early death
    • chronic eczema
      • superinfection

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