Tophus: Difference between revisions
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On a touch prep, look for needle-shaped crystals of urate. On polarized light, these will have negative birefriengence. | On a touch prep, look for needle-shaped crystals of urate. On polarized light, these will have negative birefriengence. | ||
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File:Light microscopy of a touch preparation of a gout tophus, showing urate crystals.jpg|thumb|Light microscopy of a touch preparation of a gout tophus, showing needle shaped crystals | File:Light microscopy of a touch preparation of a gout tophus, showing urate crystals.jpg|thumb|Light microscopy of a touch preparation of a gout tophus, showing needle-shaped crystals | ||
File:Birefringence microscopy of gout, annotated.jpg|Uric acid crystals in polarized light, showing negative birefringence, with yellow color when aligned parallel to the axis of the red compensator, and blue when aligned perpendicularly to it.<ref>{{cite web|url=https://emedicine.medscape.com/article/329958-workup|title=Gout and Pseudogout Workup|author=Bruce M Rothschild|website=Medscape}} Updated: Jun 30, 2020</ref> | File:Birefringence microscopy of gout, annotated.jpg|Uric acid crystals in polarized light, showing negative birefringence, with yellow color when aligned parallel to the axis of the red compensator, and blue when aligned perpendicularly to it.<ref>{{cite web|url=https://emedicine.medscape.com/article/329958-workup|title=Gout and Pseudogout Workup|author=Bruce M Rothschild|website=Medscape}} Updated: Jun 30, 2020</ref> | ||
File:Birefringence microscopy of pseudogout, annotated.jpg|In contrast, '''pseudogout''' (Calcium pyrophosphate dihydrate crystal deposition disease) displays rhombus-shaped crystals with negative birefringence. | File:Birefringence microscopy of pseudogout, annotated.jpg|In contrast, '''pseudogout''' (Calcium pyrophosphate dihydrate crystal deposition disease) displays rhombus-shaped crystals with negative birefringence. | ||
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Revision as of 11:14, 12 November 2020
Author:
Mikael Häggström [note 1]
Preparation
A tophus specimen should be sent dry to the pathology department, and not be put in formalin.[notes 1] A touch prep can be done initially, and at least if urate crystals are not initially detected, the specimen is submitted in 100% alcohol for microscopy evaluation.[notes 1]
Gross processing
Preferably make a touch prep, as well as take sections to be put in 100% alcohol and tell the histology lab to prepare it as per gout protocol.
Microscopy evaluation
On a touch prep, look for needle-shaped crystals of urate. On polarized light, these will have negative birefriengence.
-
Light microscopy of a touch preparation of a gout tophus, showing needle-shaped crystals
-
Uric acid crystals in polarized light, showing negative birefringence, with yellow color when aligned parallel to the axis of the red compensator, and blue when aligned perpendicularly to it.[1]
-
In contrast, pseudogout (Calcium pyrophosphate dihydrate crystal deposition disease) displays rhombus-shaped crystals with negative birefringence.
![Uric acid crystals in polarized light, showing negative birefringence, with yellow color when aligned parallel to the axis of the red compensator, and blue when aligned perpendicularly to it.[1]](/index.php?title=Special:Upload&wpDestFile=Birefringence_microscopy_of_gout,_annotated.jpg){kind=link}
Notes
- ↑ For a full list of contributors, see article history. Creators of images are attributed at the image description pages, seen by clicking on the images. See Patholines:Authorship for details.
Main page
References
- ↑ Bruce M Rothschild. Gout and Pseudogout Workup. Medscape. Updated: Jun 30, 2020
Image sources