Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature
Abstract Background Cryptococcosis is an increasingly common infection given the growing immunocompromised population worldwide. Cryptococcal antigen (CrAg) testing demonstrates excellent sensitivity and specificity and is the mainstay of diagnosis. However, there may be rare instances in which fals...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2023-04-01
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| Series: | BMC Infectious Diseases |
| Online Access: | https://doi.org/10.1186/s12879-023-08141-y |
| _version_ | 1797850186488217600 |
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| author | Alex N. Zimmet Grace D. Cullen Leah Mische Michael Deftos Yael Bogler Nang L. Nguyen Manoj Ray |
| author_facet | Alex N. Zimmet Grace D. Cullen Leah Mische Michael Deftos Yael Bogler Nang L. Nguyen Manoj Ray |
| author_sort | Alex N. Zimmet |
| collection | DOAJ |
| description | Abstract Background Cryptococcosis is an increasingly common infection given the growing immunocompromised population worldwide. Cryptococcal antigen (CrAg) testing demonstrates excellent sensitivity and specificity and is the mainstay of diagnosis. However, there may be rare instances in which false-negative CrAg results can delay diagnosis and early treatment, which are critical to ensure positive outcomes. Case presentation A 31-year-old man living with HIV/AIDS who was not taking antiretroviral therapy was hospitalized with fever, diarrhea, and headaches. CD4 count on presentation was 71 cells/uL, and HIV viral load was 3,194,949 copies/mL. Serum CrAg testing was initially negative, however CSF CrAg performed several days later was positive at 1:40 and blood and CSF cultures grew Cryptococcus neoformans. Colonoscopy revealed mucosal papules throughout the sigmoid colon, and tissue biopsy showed yeast within the lamina propria consistent with GI cryptococcosis. Given the high burden of disease, the original serum CrAg specimen was serially diluted and subsequently found to be positive at 1:2,560, confirming the postzone phenomenon. Conclusion Cryptococcosis has a wide array of presentations including intraluminal GI disease, as seen in this patient. While serum CrAg testing displays excellent test characteristics, it is important for clinicians to be aware of the rare instances in which false-negative results may occur in the presence of excess antigen, as in this case. |
| first_indexed | 2024-04-09T18:56:21Z |
| format | Article |
| id | doaj.art-bc94fe3e37e44e4aa0b2f95db10679c0 |
| institution | Directory Open Access Journal |
| issn | 1471-2334 |
| language | English |
| last_indexed | 2024-04-09T18:56:21Z |
| publishDate | 2023-04-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Infectious Diseases |
| spelling | doaj.art-bc94fe3e37e44e4aa0b2f95db10679c02023-04-09T11:09:27ZengBMCBMC Infectious Diseases1471-23342023-04-012311610.1186/s12879-023-08141-yDisseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literatureAlex N. Zimmet0Grace D. Cullen1Leah Mische2Michael Deftos3Yael Bogler4Nang L. Nguyen5Manoj Ray6Division of Infectious Diseases and Geographic Medicine, Stanford University School of MedicineDivision of Infectious Diseases and Geographic Medicine, Stanford University School of MedicineDivision of Infectious Diseases and Geographic Medicine, Stanford University School of MedicineDepartment of Pathology, Santa Clara Valley Medical CenterDivision of Infectious Diseases and Geographic Medicine, Stanford University School of MedicineClinical Microbiology, Santa Clara Valley Medical CenterDivision of Infectious Diseases, Kaiser Permanente Medical GroupAbstract Background Cryptococcosis is an increasingly common infection given the growing immunocompromised population worldwide. Cryptococcal antigen (CrAg) testing demonstrates excellent sensitivity and specificity and is the mainstay of diagnosis. However, there may be rare instances in which false-negative CrAg results can delay diagnosis and early treatment, which are critical to ensure positive outcomes. Case presentation A 31-year-old man living with HIV/AIDS who was not taking antiretroviral therapy was hospitalized with fever, diarrhea, and headaches. CD4 count on presentation was 71 cells/uL, and HIV viral load was 3,194,949 copies/mL. Serum CrAg testing was initially negative, however CSF CrAg performed several days later was positive at 1:40 and blood and CSF cultures grew Cryptococcus neoformans. Colonoscopy revealed mucosal papules throughout the sigmoid colon, and tissue biopsy showed yeast within the lamina propria consistent with GI cryptococcosis. Given the high burden of disease, the original serum CrAg specimen was serially diluted and subsequently found to be positive at 1:2,560, confirming the postzone phenomenon. Conclusion Cryptococcosis has a wide array of presentations including intraluminal GI disease, as seen in this patient. While serum CrAg testing displays excellent test characteristics, it is important for clinicians to be aware of the rare instances in which false-negative results may occur in the presence of excess antigen, as in this case.https://doi.org/10.1186/s12879-023-08141-y |
| spellingShingle | Alex N. Zimmet Grace D. Cullen Leah Mische Michael Deftos Yael Bogler Nang L. Nguyen Manoj Ray Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature BMC Infectious Diseases |
| title | Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature |
| title_full | Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature |
| title_fullStr | Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature |
| title_full_unstemmed | Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature |
| title_short | Disseminated cryptococcosis with gastrointestinal involvement and false-negative cryptococcal antigen testing due to postzone phenomenon: a case report and review of the literature |
| title_sort | disseminated cryptococcosis with gastrointestinal involvement and false negative cryptococcal antigen testing due to postzone phenomenon a case report and review of the literature |
| url | https://doi.org/10.1186/s12879-023-08141-y |
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