Editing Stones: Evaluation and Medical Management (section)

=== Laboratory ===

==== <span style="color:#ff0000">Urinalysis +/- culture +/- microscopy</span> ====
* '''<span style="color:#ff0000">Urinalysis should include pH</span>'''
** '''<span style="color:#ff0000">pH > 7.0 is suggestive of infection lithiasis or RTA</span>'''
** '''<span style="color:#ff0000">pH < 5.5 suggests uric acid lithiasis secondary to gouty diathesis</span>'''
* '''Urine culture'''
** '''Should be obtained in patients with a urinalysis suggestive of UTI.'''
**'''Presence of urea-splitting organisms, such as Proteus species, raises the possibility of struvite stones'''
**Many infected calculi will harbor bacteria even after treatment with broad-spectrum antibiotics
** Half of infected calculi grow bacterial cultures that are different from the preoperative urine specimen
*'''Urine microscopy'''
**'''Identify crystals pathognomonic of stone type.'''

==== <span style="color:#ff0000">Serum chemistries</span> ====

*'''<span style="color:#ff0000">Includes</span>''' 
*#'''<span style="color:#ff0000">Electrolytes (Na, K, Cl, HCO3)</span>'''
*#'''<span style="color:#ff0000">Calcium</span>'''
*#'''<span style="color:#ff0000">Uric acid</span>'''
*#'''<span style="color:#ff0000">Creatinine</span>'''
* May suggest underlying medical conditions associated with stone disease (e.g., primary hyperparathyroidism, gout, RTA type 1 or other metabolic derangements)
* '''Assessment of underlying renal function is necessary'''

==== <span style="color:#ff0000">Parathyroid hormone (PTH)</span> ====
*'''<span style="color:#ff0000">Indicated as part of the screening evaluation if primary hyperparathyroidism is suspected</span>'''
**'''<span style="color:#ff0000">Primary hyperparathyroidism should be suspected when (3):</span>'''
**#Mid-range PTH despite '''<span style="color:#ff0000">high or high normal serum calcium</span>'''
**#'''<span style="color:#ff0000">Increased urinary calcium</span>'''
**#'''<span style="color:#ff0000">Predominantly calcium phosphate stone composition</span>'''
*'''Measurement of vitamin D levels may be helpful as''' '''low vitamin D levels may mask primary hyperparathyroidism, or contribute to secondary hyperparathyroidism.'''
*A high or high normal intact PTH in these settings should prompt further endocrine evaluation, imaging or referral for consideration of parathyroidectomy.

==== Stone composition, if available ====
*'''When a stone is available, a stone analysis should be obtained at least once.'''
*Can direct metabolic investigation or potentially obviate the need for a complete metabolic evaluation
*'''<span style="color:#ff0000">Calcium phosphate stone composition associated with:</span>'''
*#'''<span style="color:#ff0000">RTA Type 1</span>'''
*#'''<span style="color:#ff0000">Primary hyperparathyroidism</span>'''
*#'''<span style="color:#ff0000">Medullary sponge kidney</span>'''
*#'''<span style="color:#ff0000">Use of carbonic anhydrase inhibitors</span>'''