questions 6

Bruton Agammaglobulinemia

Topic updated on 09/01/17 4:09am

  • A 6-year-old boy presents to the hospital with a severe upper respiratory infection requiring  hospitalization. Chart review reveals that he has presented multiple times to the emergency room and primary care physician’s office for a variety of infections, including otitis media, upper respiratory infections, pneumonia, and sinusitis. When detailing family history, it is found that his maternal uncle died of an infection as a child. Lab findings include decreased levels of IgG, IgM, and IgA.
  • Primary humoral immunodeficiency characterized by decreased immunoglobulins
  • Genetics
    • X-linked recessive
      • seen in male children
  • Pathogenesis
    • defect in Bruton tyrosine kinase (BTK)
    • defective maturation of B-cells
      • impaired signaling from pre-B-cell receptor 
      • ↓ B-cells
      • ↓ production of all classes of Ig
    • impaired antibody immune response
  • Symptoms
    • recurrent infections
      • especially after 6 months old (↓ maternal IgG)
      • Streptococcus pneumoniae, Hemophilus influenzae, Streptoccocus pyogenes, and Pseudomonas
    • increased susceptibility to encapsulated bacteria and blood-borne viruses
      • due to opsonization defect
  • Physical exam
    • absent/scant lymphoid tissues (tonsils/lymph nodes)
  • Diagnosis based on family history, clinical history, and exam
  • Serologies
    • ↓ all classes of Ig
    • ↓ levels of B-cells
    • normal T-cells
  • Diagnosis confirmed with DNA, mRNA, or protein analysis showing mutation in BTK
Differential Diagnosis
  • Common variable immunodeficiency
  • Severe combined immunodeficiency
  • Transient hypogammaglobulinemia of infancy
  • Antibiotics for infections
  • Regular IVIG infusions
Prognosis, Prevention, and Complications
  • Prognosis
    • normal prognosis with regular IVIG therapy and early detection
  • Prevention
    • screening in newborns
    • regular IVIG to prevent infections
  • Complications
    • small risk of malignancy


Qbank (4 Questions)

(M1.IM.1) Which of the following patient presentations seen in a pediatric immunology clinic is most consistent with a diagnosis of Bruton's agammaglobulinemia? Topic Review Topic

1. A 15-month-old girl who has had repeated otitis media, pneumonia, and progressive clumsiness since beginning to walk in the past three months
2. A 10-month-old boy who has had recurrent viral infections as well as hypocalcemia during neonatal period
3. A 4-year-old girl who has had repeated oral candidasis in the past nine months
4. A 9-month-old boy who has had recurrent otitis media and pneumococcal pneumonia in the past three months
5. A 7-month-old boy who has had recurrent pneumococcal pneumonia, eczema, and easy bruising in the past four months

(M1.IM.30) You are seeing a 4-year-old boy in clinic who is presenting with concern for a primary immune deficiency. He has an unremarkable birth history, but since the age of 6 months he has had recurrent otitis media, bacterial pneumonia, as well as two episodes of sinusitis, and four episodes of conjunctivitis. He has a maternal uncle who died from sepsis secondary to H. influenza pneumonia. If you drew blood work for diagnostic testing, which of the following would you expect to find? Topic Review Topic

1. Abnormally low number of B cells
2. Abnormally low number of T cells
3. Abnormally high number of B cells
4. Abnormally high number of T cells
5. Elevated immunoglobulin levels

(M1.IM.57) A 7-month-old Caucasian male presents with recurrent sinusitis and pharyngitis. The parents say that the child has had these symptoms multiple times in the past couple of months and a throat swab sample reveals the presence of Streptoccocus pneumoniae. Upon workup for immunodeficiency it is noted that serum levels of immunoglobulins are extremely low but T-cell levels are normal. Which of the following molecules is present on the cells that this patient lacks? Topic Review Topic

1. CD4
2. CD8
3. CD3
4. CD19
5. NKG2D

(M1.IM.74) A father brings his 9-month-old child into the pediatrician's office because he is concerned about his child's health. He states that starting a few months ago, the child has had recurrent infections, with the most recent being a Giardial infection. On physical exam, the child is well-appearing but the pediatrician notes an absence of tonsils. Concerned for a possible immunodeficiency, the pediatrician obtains Ig levels which demonstrates decreased IgM, IgG, IgA, and IgE. Which of the following pedigrees best represents the mode of inheritance of this patient's condition? Topic Review Topic
FIGURES: A   B   C   D   E  

1. Figure A
2. Figure B
3. Figure C
4. Figure D
5. Figure E

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