USMLE Forum Archives - USMLE Step 1 - Pathology 35
Pathology 35
TheOne - 11-21-06 16:20
A 12-year-old girl presents with a skin abscess. The causative organism is found to be Staphylococcus aureus. Over the past year, she has had several similar abscesses, as well as two bouts of aspergillosis. Which of the following is the most likely explanation for her repeated infections?
A. Defective chemotactic response
B. Defective NADPH oxidase
C. Deficiency of C5
D. IgA deficiency
E. Thymic hypoplasia
TheOne - 11-21-06 16:20
A 12-year-old girl presents with a skin abscess. The causative organism is found to be Staphylococcus aureus. Over the past year, she has had several similar abscesses, as well as two bouts of aspergillosis. Which of the following is the most likely explanation for her repeated infections?
A. Defective chemotactic response
B. Defective NADPH oxidase
C. Deficiency of C5
D. IgA deficiency
E. Thymic hypoplasia
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#2
Re: Pathology 35 Gordo - 11-23-06 15:41 This patient is obviosly immunodepressed. It could be IgA deficiency.
#4
Re: Pathology 35 Youngdoctor - 11-24-06 17:36 A 12-year-old girl presents with a skin abscess. The causative organism is found to be Staphylococcus aureus. Over the past year, she has had several similar abscesses, as well as two bouts of aspergillosis. Which of the following is the most likely explanation for her repeated infections?
A. Defective chemotactic response
B. Defective NADPH oxidase
C. Deficiency of C5
D. IgA deficiency
E. Thymic hypoplasia
Why do you think that is defective NADPH oxidase?.Can any one give the explanation.I am thinking related to IgA deficiency.
#5
Re: Pathology 35
TheOne - 11-26-06 16:31 Explanation: The correct answer is B. A history of recurrent infection with S. aureus and S. aspergillus suggests a diagnosis of chronic granulomatous disease, which is caused by a defect in the NADPH oxidase of neutrophils, resulting in an inability to generate toxic oxygen metabolites following phagocytosis. Patients become susceptible to certain opportunistic infections, particularly those caused by S. aureus, S. aspergillus, Nocardia, and Salmonella. Defective chemotactic response (choice A), seen in diseases such as Chédiak-Higashi syndrome and lazy-leukocyte syndrome, would make patients more susceptible to infections by bacteria such as Staphylococci and Streptococci. Deficiency of C5 (choice C), a complement component, would make patients prone to infection by gram-negative bacteria, especially Neisseria species. IgA deficiency (choice D) represents the most common immunodeficiency and would present with increased predisposition to autoimmune disorders, respiratory infections, and milk allergy. Thymic hypoplasia (choice E) is caused by defective development of the 3rd and 4th pharyngeal pouches. The result is decreased T-cell levels, making patients more prone to viral and fungal infections. They also will exhibit hypocalcemia and other signs of parathyroid insufficiency.
#6
Re: Pathology 35 galaxy - 05-28-10 02:29 A 12-year-old girl presents with a skin abscess. The causative organism is found to be Staphylococcus aureus. Over the past year, she has had several similar abscesses, as well as two bouts of aspergillosis. Which of the following is the most likely explanation for her repeated infections?
B. Defective NADPH oxidase
#8
Re: Pathology 35 bingousmle - 06-30-10 21:54 patients who are prone to certain opportunistic infection like the ones caused by S. aureus, S. aspergillus, Nocardia, and Salmonella think of Defective NADPH oxidase
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