questions 5

Chronic Granulomatous Disease

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Topic updated on 05/18/17 3:54pm

Snapshot
  • A 2-month-old boy presents with a 2-day history of fever and a painful bump on his rear-end. On exam, there is a fluctuant, erythematous bump with purulent material draining. The abscess is drained and cultured, and the patient is started on antibiotics. The cultures come back positive for S. aureus. This is his second episode of a S. aureus-induced abscess. A nitroblue tetrazolium test is negative.
Introduction
  • Chronic granulomatous disease (CGD) is a rare primary immunodeficiency of phagocytes
  • Genetics
    • X-linked recessive
    • both result in deficiency in NADPH oxidase
  • Epidemiology
    • males > females due to inheritance pattern
  • Pathogenesis
    • recall normal physiology
      • NADPH oxidase is important in respiratory or oxidative burst
      • results in rapid release of reactive oxygen species such as superoxide
    • CGD patients lack the oxidative burst
      • can only use peroxide from microorganisms to make reactive oxygen species
      • ↑ risk of catalase-positive species (S. aureus, E. coli, Aspergillus, Candida, etc.) 
  • Leads to granulomas
Presentation
  • Symptoms
    • often appear in first year of life with recurrent pyogenic infections
    • recurrent infection with catalase-positive organisms
      • pneumonias
      • aspergillosis
      • skin abscesses
      • pulmonary abscesses
      • chronic diarrhea
    • failure to thrive
  • Physical exam
    • short stature
    • eczematoid dermatitis
    • hepatomegaly
Evaluation
  • Flow cytometry reduction of dihydrorhodamine
    • abnormal
    • can detect X-linked carrier status
    • cannot differentiate oxidase-positive from oxidase-negative phagocyte subpopulations in CGD carriers
  • Nitroblue tetrazolium dye reduction test
    • negative finding = incubated leukocytes do not turn the plate blue
  • Cytochrome c reduction assay
    • measures production of reactive oxygen species
Differential Diagnosis
  • IgA deficiency
  • HIV/AIDs
  • Other primary immunodeficiencies
Treatment
  • INF-γ
  • Antibacterial and antifungal prophylaxis
  • Only curative therapy
    • hematopoietic stem cell transplant
Prognosis, Prevention, and Complications
  • Prognosis
    • improving with treatment
    • 50% survival rate to age 30-40
  • Prevention
    • antifungals and antibiotics
  • Complications
    • severe fungal infections are often determinant of survival


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Qbank (3 Questions)

TAG
(M1.IM.53) A 3-year-old female is found to have unusual susceptibility to infections by catalase-producing organisms. This patient likely has a problem with the function of which of the following cell types? Topic Review Topic

1. B cells
2. T cells
3. Natural killer cells
4. Neutrophils
5. Eosinophils

PREFERRED RESPONSE ▶
TAG
(M1.IM.68) A 5-year-old female suffers from recurrent infections by Aspergillus species, Pseudomonas species, and Staphylococcus aureus. The patient's neutrophils are examined in the laboratory and they fail to react during the nitroblue tetrazolium test. Which of the following is most likely dysfunctional in this patient? Topic Review Topic

1. Lymphocytes
2. Immunoglobulin class switching
3. Superoxide dismutase
4. Myeloperoxidase
5. Respiratory burst

PREFERRED RESPONSE ▶
TAG
(M1.IM.74) A father brings his 3-year-old son to the pediatrician because he is concerned about his health. He states that throughout his son's life he has had recurrent infections despite proper treatment and hygiene. Upon reviewing the patient's chart, the pediatrician notices that the child has been infected multiple times with S. aureus, Aspergillus, and E. coli. Which of the following would confirm the most likely cause of this patient's symptoms? Topic Review Topic

1. Negative nitroblue-tetrazolium test
2. Normal dihydrorhodamine (DHR) flow cytometry test
3. Positive nitroblue-tetrazolium test
4. Increased IgM, Decreased IgG, IgA, and IgE
5. Increased IgE and IgA, Decreased IgM

PREFERRED RESPONSE ▶
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