Histoplasmosis other diagnostic studies: Difference between revisions
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==Overview== | ==Overview== | ||
The gold standard for diagnosis of | The gold standard for diagnosis of [[Histoplasma capsulatum|histoplasma]] infection is direct visualization of the oviod [[yeast]] cells in the tissue samples and body fluid specimen. Antigen testing is an useful method for rapid diagnosis of [[Histoplasma capsulatum|histoplasma]] infection. | ||
==Other Diagnostic Studies== | ==Other Diagnostic Studies== | ||
===Microscopy=== | ===Microscopy=== | ||
*The gold standard for diagnosis of | *The gold standard for diagnosis of [[Histoplasmosis|histoplasma]] infection is direct visualization of the oviod [[yeast]] cells in the tissue samples and body fluid specimen. | ||
*Histoplasma capsulatum is characterized by a budding yeast connected with a narrow base and is mostly identified within the macrophages and monocytes. | *[[Histoplasma capsulatum]] is characterized by a budding [[yeast]] connected with a narrow base and is mostly identified within the [[macrophages]] and [[monocytes]]. | ||
*In immunocompetent people, immune response by the macrophages results in the formation of a granuloma and the yeast forms are demonstrated within the histiocytes in the granuloma. However in patients with disseminated infection the yeast forms can be demonstrated in the histiocytes scattered throughout the organ and are not confined to the granulomas alone. | *In [[immunocompetent]] people, [[immune response]] by the [[macrophages]] results in the formation of a [[granuloma]] and the [[yeast]] forms are demonstrated within the [[histiocytes]] in the [[granuloma]]. However in patients with [[Disseminated disease|disseminated]] infection the [[yeast]] forms can be demonstrated in the [[histiocytes]] scattered throughout the organ and are not confined to the [[granulomas]] alone. | ||
*Different stains such as the gram stain, Giemsa stain, Hematoxylin-eosin stain, Mucicarmine stain, PAS stain and Wright-Giemsa stain are useful for demonstration of the granulomas and the yeast forms in the tissue specimen or body fluid samples. | *Different stains such as the [[gram stain]], [[Giemsa stain]], Hematoxylin-eosin stain, [[Mucicarmine]] stain, [[PAS stain|PAS]] stain and Wright-Giemsa stain are useful for demonstration of the [[granulomas]] and the [[yeast]] forms in the tissue specimen or body fluid samples. | ||
===Culture=== | ===Culture=== | ||
*Culture is positive 50% to 85% patients with disseminated histoplasmosis and chronic pulmonary histoplasmosis. | *[[Blood culture|Culture]] is positive 50% to 85% patients with [[Disseminated disease|disseminated]] [[histoplasmosis]] and chronic pulmonary [[histoplasmosis]]. | ||
*Culture takes 4 weeks to grow and the mold appears as a suede-like or cottony mycelium. Microscopic examination of the mold demonstrate characteristic large, rounded tuberculate macroconidia. | *[[Blood culture|Culture]] takes 4 weeks to grow and the [[mold]] appears as a suede-like or cottony [[mycelium]]. Microscopic examination of the [[mold]] demonstrate characteristic large, rounded tuberculate macroconidia. | ||
===Antigen Testing=== | ===Antigen Testing=== | ||
*Antigen testing is an useful method for rapid diagnosis of histoplasma infection. Galactomannan antigen can be detected in the blood or urine samples and is positive in majority of patients with acute pulmonary histoplasmosis and disseminated histoplasmosis. | *Antigen testing is an useful method for rapid diagnosis of [[Histoplasma capsulatum|histoplasma]] infection. [[Galactomannan]] [[antigen]] can be detected in the [[blood]] or urine samples and is positive in majority of patients with acute pulmonary [[histoplasmosis]] and [[Disseminated disease|disseminated]] [[histoplasmosis]]. | ||
*Histoplasma antigen detection in urine and/or serum is the most widely used and most sensitive method for diagnosing acute histoplasmosis. | *[[Histoplasma capsulatum|Histoplasma]] [[Antigen detection test|antigen detection]] in [[urine]] and/or [[serum]] is the most widely used and most sensitive method for diagnosing acute [[histoplasmosis]]. | ||
===Antibody Testing=== | ===Antibody Testing=== | ||
*'''Antibody tests:''' Because development of antibodies to Histoplasma can take two to six weeks, antibody tests are not as useful as antigen detection tests in diagnosing acute histoplasmosis or in immunosuppressed persons, who may not mount a strong immune response. | *'''Antibody tests:''' Because development of [[antibodies]] to [[Histoplasmosis|Histoplasma]] can take two to six weeks, antibody tests are not as useful as [[Antigen detection test|antigen detection tests]] in diagnosing [[acute]] [[histoplasmosis]] or in [[immunosuppressed]] persons, who may not mount a strong [[immune response]]. | ||
**'''Immunodiffusion (ID):''' | **'''Immunodiffusion (ID):''' It can help differentiate between chronic or severe acute infection. | ||
**'''Complement Fixation (CF):''' Complement-fixing antibodies may take up to 6 weeks to appear after infection. | **'''Complement Fixation (CF):''' [[Complement-fixation|Complement]]-fixing antibodies may take up to 6 weeks to appear after infection. [[Complement fixation]] is more sensitive but less specific than [[immunodiffusion]]. | ||
===Molecular Testing=== | ===Molecular Testing=== | ||
*Polymerase chain reaction can help in the diagnosis of histoplasma infection, but the role is uncertain as the results are not consistent with the infection status. | *[[Polymerase chain reaction]] can help in the diagnosis of [[Histoplasma capsulatum|histoplasma]] infection, but the role is uncertain as the results are not consistent with the infection status. | ||
==Gallery== | ==Gallery== | ||
Revision as of 19:14, 8 May 2017
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Histoplasmosis Microchapters |
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Treatment |
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Histoplasmosis other diagnostic studies On the Web |
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American Roentgen Ray Society Images of Histoplasmosis other diagnostic studies |
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Risk calculators and risk factors for Histoplasmosis other diagnostic studies |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Aravind Kuchkuntla, M.B.B.S[2]
Overview
The gold standard for diagnosis of histoplasma infection is direct visualization of the oviod yeast cells in the tissue samples and body fluid specimen. Antigen testing is an useful method for rapid diagnosis of histoplasma infection.
Other Diagnostic Studies
Microscopy
- The gold standard for diagnosis of histoplasma infection is direct visualization of the oviod yeast cells in the tissue samples and body fluid specimen.
- Histoplasma capsulatum is characterized by a budding yeast connected with a narrow base and is mostly identified within the macrophages and monocytes.
- In immunocompetent people, immune response by the macrophages results in the formation of a granuloma and the yeast forms are demonstrated within the histiocytes in the granuloma. However in patients with disseminated infection the yeast forms can be demonstrated in the histiocytes scattered throughout the organ and are not confined to the granulomas alone.
- Different stains such as the gram stain, Giemsa stain, Hematoxylin-eosin stain, Mucicarmine stain, PAS stain and Wright-Giemsa stain are useful for demonstration of the granulomas and the yeast forms in the tissue specimen or body fluid samples.
Culture
- Culture is positive 50% to 85% patients with disseminated histoplasmosis and chronic pulmonary histoplasmosis.
- Culture takes 4 weeks to grow and the mold appears as a suede-like or cottony mycelium. Microscopic examination of the mold demonstrate characteristic large, rounded tuberculate macroconidia.
Antigen Testing
- Antigen testing is an useful method for rapid diagnosis of histoplasma infection. Galactomannan antigen can be detected in the blood or urine samples and is positive in majority of patients with acute pulmonary histoplasmosis and disseminated histoplasmosis.
- Histoplasma antigen detection in urine and/or serum is the most widely used and most sensitive method for diagnosing acute histoplasmosis.
Antibody Testing
- Antibody tests: Because development of antibodies to Histoplasma can take two to six weeks, antibody tests are not as useful as antigen detection tests in diagnosing acute histoplasmosis or in immunosuppressed persons, who may not mount a strong immune response.
- Immunodiffusion (ID): It can help differentiate between chronic or severe acute infection.
- Complement Fixation (CF): Complement-fixing antibodies may take up to 6 weeks to appear after infection. Complement fixation is more sensitive but less specific than immunodiffusion.
Molecular Testing
- Polymerase chain reaction can help in the diagnosis of histoplasma infection, but the role is uncertain as the results are not consistent with the infection status.
Gallery
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![Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]](/images/4/4e/Histoplasmosis09.jpeg)
Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]
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![Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]](/images/5/5b/Histoplasmosis08.jpeg)
Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]
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![Magnified 1250x, this H&E-stained liver tissue specimen reveals the presence of yeast-staged Histoplasma capsulatum fungal organisms inside a number of phagocytic macrophages. From Public Health Image Library (PHIL). [1]](/images/7/74/Histoplasmosis06.jpeg)
Magnified 1250x, this H&E-stained liver tissue specimen reveals the presence of yeast-staged Histoplasma capsulatum fungal organisms inside a number of phagocytic macrophages. From Public Health Image Library (PHIL). [1]
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![This Giemsa-stained photomicrograph reveals a histiocyte within which numerous Histoplasma capsulatum fungal organisms in their yeast-stage of development were contained. From Public Health Image Library (PHIL). [1]](/images/3/3a/Histoplasmosis05.jpeg)
This Giemsa-stained photomicrograph reveals a histiocyte within which numerous Histoplasma capsulatum fungal organisms in their yeast-stage of development were contained. From Public Health Image Library (PHIL). [1]
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![This photomicrograph reveals the presence of Histoplasma capsulatum fungal organisms in any unknown specimen, which were in the organism's yeast phase, displaying numerous microconidia. From Public Health Image Library (PHIL). [1]](/images/b/bc/Histoplasmosis04.jpeg)
This photomicrograph reveals the presence of Histoplasma capsulatum fungal organisms in any unknown specimen, which were in the organism's yeast phase, displaying numerous microconidia. From Public Health Image Library (PHIL). [1]
![Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]](/index.php/File:Histoplasmosis09.jpeg)
![Magnified 125X, "digested", then stained using a fluorescent antibody-staining technique, this photomicrograph reveals the presence of Histoplasma capsulatum antigens in this human lung tissue specimen. From Public Health Image Library (PHIL). [1]](/index.php/File:Histoplasmosis08.jpeg)
![Magnified 1250x, this H&E-stained liver tissue specimen reveals the presence of yeast-staged Histoplasma capsulatum fungal organisms inside a number of phagocytic macrophages. From Public Health Image Library (PHIL). [1]](/index.php/File:Histoplasmosis06.jpeg)
![This Giemsa-stained photomicrograph reveals a histiocyte within which numerous Histoplasma capsulatum fungal organisms in their yeast-stage of development were contained. From Public Health Image Library (PHIL). [1]](/index.php/File:Histoplasmosis05.jpeg)
![This photomicrograph reveals the presence of Histoplasma capsulatum fungal organisms in any unknown specimen, which were in the organism's yeast phase, displaying numerous microconidia. From Public Health Image Library (PHIL). [1]](/index.php/File:Histoplasmosis04.jpeg)