Primary Immunodeficiencies – USMLE Examinations

by / Monday, 28 June 2010 / Published in Internal Medicine


IgA Deficiency

  • Is the most common primary immunodeficiency, and it is often asymptomatic
  • Causes recurrent respiratory and GI infections
  • Someone receiving blood products may develop anaphylaxis, which should make you think of an IgA deficiency
  • Never give these patients immunoglobulin’s


  • Manage and treat infections as they arise

Bruton’s Agammaglobulinemia

  • Is an x-linked disorder affecting males
  • Patients present with infections starting around 6 months of age
  • Recurrent sinopulmonary infections due to Strep or Hemophilus organisms are classic


  • Infusion of IV Ig’s

Common Variable Immunodeficiency

  • Is a condition that presents in both men and women
  • Usually only presents when they are adults
  • Patient presents with recurrent sinopulmonary infections
  • May get sprue-like abdominal disorders (malabsorbtion, diarrhea, steatorrhea)


  • IgG levels are low


  • Infusions of IVIG is required since IgG levels are low

Severe Combined Immunodeficiency

  • An AR or x-linked disorder
  • Commonly caused by adenosine deaminase deficiency
  • There is a B and T cell defect, thus patient has severe infections early in life
  • These are the so called “bubble babies”, and require isolation to prevent life-threatening infections

Wiskott-Aldrich Syndrome

  • An x-linked recessive disorder affecting only males
  • There is a classic triad of eczema, recurring infections, and thrombocytopenia

Chediak-Higashi Syndrome

  • Due to a defect in microtubule polymerization
  • Giant granules in neutrophils
  • Oculocutaneous albinism
  • Recurring infections

Chronic Granulomatous Disease

  • Usually an x-linked recessive disorder affecting males
  • There is a defect in NADPH oxidase, causing recurring infections due to catalase (+) organisms (Staph, Pseudomonas,etc)
  • Diagnostic test involves nitroblue tetrazolium dye (normally gets reduced by granulocytes) – measures respiratory burst, which is lacking in these patients

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