Tophus: Difference between revisions
Jump to navigation
Jump to search
Modified |
Note |
||
| (8 intermediate revisions by the same user not shown) | |||
| Line 4: | Line 4: | ||
}} | }} | ||
==Preparation== | ==Preparation== | ||
A tophus specimen should be sent '''dry''' to the pathology department, and '''not''' be put in formalin.<ref group= | A tophus specimen should be sent '''dry''' to the pathology department, and '''not''' be put in formalin.<ref group=note name=dissolves>Formalin dissolves the crystals.</ref> | ||
==Gross processing== | |||
[[File:Gross pathology of tophus.jpg|thumb|A large tophus.]] | |||
Preferably make a touch prep for polarized light microscopy. At least if urate crystals are not initially detected, take sections to be put in 100% alcohol and tell the histology lab to prepare it as per gout protocol.<ref group=note name=dissolves/> With characteristic crystals on a touch prep, sections may possibly be submitted in formalin.<ref group=note name=dissolves/> | |||
==Microscopy evaluation== | ==Microscopy evaluation== | ||
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. | ||
<gallery mode=packed> | <gallery mode=packed heights=180> | ||
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: | 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''', also called calcium pyrophosphate dihydrate (CPPD) crystal deposition disease) displays rhombus-shaped or parallelogram-shaped crystals with negative birefringence. | |||
File:Calcium pyrophosphate dihydrate crystals without and with condenser.jpg|To look for crystals in a regular light microscope, look without '''condenser''' (right image) if possible, wherein crystal outlines are more clear than with condenser (left image). CPPD crystals are depicted. | |||
</gallery> | </gallery> | ||
{{Bottom}} | {{Bottom}} | ||
Latest revision as of 16:49, 19 June 2022
Author:
Mikael Häggström [note 1]
Preparation
A tophus specimen should be sent dry to the pathology department, and not be put in formalin.[note 2]
Gross processing
Preferably make a touch prep for polarized light microscopy. At least if urate crystals are not initially detected, take sections to be put in 100% alcohol and tell the histology lab to prepare it as per gout protocol.[note 2] With characteristic crystals on a touch prep, sections may possibly be submitted in formalin.[note 2]
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]](https://upload.wikimedia.org/wikipedia/commons/thumb/b/b2/Birefringence_microscopy_of_gout%2C_annotated.jpg/500px-Birefringence_microscopy_of_gout%2C_annotated.jpg?utm_source=commons.wikimedia.org&utm_campaign=imageinfo&utm_content=thumbnail)
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, also called calcium pyrophosphate dihydrate (CPPD) crystal deposition disease) displays rhombus-shaped or parallelogram-shaped crystals with negative birefringence. -
To look for crystals in a regular light microscope, look without condenser (right image) if possible, wherein crystal outlines are more clear than with condenser (left image). CPPD crystals are depicted.
![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]](/File:Birefringence_microscopy_of_gout,_annotated.jpg)
Notes
Main page
References
- ↑ Bruce M Rothschild. Gout and Pseudogout Workup. Medscape. Updated: Jun 30, 2020
Image sources