Stones: Evaluation and Medical Management: Difference between revisions

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=== Plain Abdominal Film ===
=== Plain Abdominal Film ===
* Can identify nephrocalcinosis, suggestive of RTA
*'''Findings'''
* '''Radiolucent stones (6):'''
**Can identify nephrocalcinosis, suggestive of RTA
** '''Uric acid'''
** '''Radiolucent stones (6):'''
** '''Matrix'''
*** '''Uric acid'''
** '''Medication stones (4):'''
*** '''Matrix'''
***'''Xanthine'''
*** '''Medication stones (4):'''
***'''Triamterene'''
****'''Xanthine'''
***'''2,8-dihydroxyadenine'''
****'''Triamterene'''
***'''Indivir'''
****'''2,8-dihydroxyadenine'''
* '''Radioopaque stones (4):'''  
****'''Indivir'''
**'''Calcium oxalate'''
** '''Radioopaque stones (4):'''  
**'''Calcium phosphate'''
***'''Calcium oxalate'''
**'''Poorly radioopaque:'''
***'''Calcium phosphate'''
***'''Magnesium ammonium phosphate (struvite)'''  
***'''Poorly radioopaque:'''
***'''Cystine stones'''
****'''Magnesium ammonium phosphate (struvite)'''  
**** '''Although magnesium ammonium phosphate and cystine stones are often radioopaque, they are not as dense as calcium oxalate or calcium phosphate stones'''
****'''Cystine stones'''
* Underestimates >90% of stones >10mm
***** '''Although magnesium ammonium phosphate and cystine stones are often radioopaque, they are not as dense as calcium oxalate or calcium phosphate stones'''
*Advantage(s)
**Availability
**Relatively low radiation exposure
**Cost
*'''Disadvantages'''
**'''Inability to visualize small stones'''
**'''Inability to visualize stones due to overlying/underlying anatomy (bones, phleboliths, etc.)'''
**'''Underestimates >90% of stones >10mm'''


=== Ultrasound ===
=== Ultrasound ===
* '''Limitations (2):'''
* '''Advantages'''
**Availability
**No radiation exposure
**Cost
*'''Disadvantages (2):'''
** '''Inability to visualize most ureteral stones'''
** '''Inability to visualize most ureteral stones'''
** '''Poor correlation between measured and actual stone size and location'''
** '''Poor correlation between measured and actual stone size and location'''
*** '''US and CT measurements correlate 2/3 of the time'''
*** '''If stone'''  
**** '''With stone <10mm, US underestimates size of stone 1/3 of the time'''
****'''<10mm, US underestimates size of stone 1/3 of the time'''
**** '''With stone >10mm, US overestimates size of stone 1/3 of the time'''
**** '''>10mm, US overestimates size of stone 1/3 of the time'''
***US and CT measurements correlate 2/3 of the time


=== '''CT''' ===
=== '''CT''' ===
* '''Pure uric acid stones have much lower Hounsfield units than calcium types'''
* '''Findings'''
*'''Pure uric acid stones have much lower Hounsfield units than calcium types'''


* '''Forniceal extravasation'''
* '''Forniceal extravasation'''
** Usually associated with a small distal ureteral calculus.
** Usually associated with a small distal ureteral calculus.
** '''Should be similarly to other ureteral stones:''' intervention should be undertaken when there is an associated fever, nausea/vomiting, or unrelenting pain. Otherwise, conservative observation is appropriate.
** '''Should be similarly to other ureteral stones:''' intervention should be undertaken when there is an associated fever, nausea/vomiting, or unrelenting pain. Otherwise, conservative observation is appropriate.
*Advantages
**Most sensitive modality for stones
*Disadvantages
**Exposure to radiation
**Availability
**Cost


== Diagnosis and Evaluation of Stone Disease ==
== Diagnosis and Evaluation of Stone Disease ==