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Old 06-13-2012
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Immunology This patient is at greatest risk of infection from which of the following agents?

A 68-year old man has been relatively healthy all of his life, bothered only by occasional mild diarrheeal illness. On physical examination, his temperature is 37.1 C and blood pressure is 125/85 mm Hg. Laboratory studies show a total WBC count of 6900/mm3 with 72% segmented neutrophils, 3% bands, 18% lymphocytes and 7% monocytes. Serum immunoglobulin levels are IgG 1.9 g/dl, IgM 0.3 g/dl, and IgA 0.01 g/dl. The ANA test result is negative. The skin test result for mumps and Candida antigens is positive. This patient is at greatest risk of infection from which of the following agents?

A) Pneumocistic jiroveci
B) Streptococcus pneumoniae
C) Hepatitis B virus
D) Aspergillus flavus
E) Herpes simples virus

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Old 06-13-2012
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asperagellus?
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Last edited by drhma; 06-13-2012 at 03:14 AM.
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IgA levels are low.. Strept pneumoniae??

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A. ?
looks like problem with T cells?
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I would guess Strep pneumo...IgA is extremely low, increased risk for IgA protease organisms
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Old 06-13-2012
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Same here.....im not sure whether serum IgA levels correlate with the secretory IgA in the intestine or other mucosal surfaces, but going by history of mild diarrhea's and age related immunodeficiency ill choose strep pneumo..!!!!

im waiting for the explanation
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Old 06-13-2012
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A? I'm thinking?

whats the rite answer???
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I'll go with (B)Streptococcus pneumoniae: Laboratory studies show a total WBC count of 6900/mm3 with 72% segmented neutrophils and A 68-year old
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mmm... B....?
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I think its B) Strep Pneumo as well.

Here's my explanation -

Low Immunoglobulins: looks like B cell and CD4+ T helper cells defect.
Viruses activate the CD8+ CTL's so I eliminated choices A, C and E.
Aspergillus is not a virus but it wouldn't provoke an Inflammatory response of neutrophils, it would cause lymphocytosis.

So low IgA, B cell defect, given the pts age, and inflammatory response of neutrophils, I'd go with B) Strep Pneumo.
This was widely based on a method of elimination .. not really sure what the defect or pathology is here!
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i would go with b answer, as candida antigens is positive so pt is most likely immunosuppresive so would go with pneumocystis jiroveci, b/c its common in immunosuppresive pts,..........waiting for rite answer
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Default correct answer :)

Correct answer is B) Streptococcus pneumoaniae

This man has a selective (isolated) IgA deficiency. Such persons are bothered by minor recurrent sinupulmonary infections and by diarrhea.
Pneumocistic jiroveci are seen with patients with more severe acquired or inherited immunodeficiency disorders, particularly those with AIDS, which affect cell-mediated immunity.
Hepatitis infections are not directly related to immunodeficiency states., although AIDS patients with a history of injection drug use are often infected with hepatitis B or C.
Resistance against fungal and viral infection is mediated by T cells.
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