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Stones: Evaluation and Medical Management: Difference between revisions

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****Minute calcifications seen in early stages may not be visible
****Minute calcifications seen in early stages may not be visible
***'''Can give rise to renal colic and hydronephrosis from dislodged calcific foci'''
***'''Can give rise to renal colic and hydronephrosis from dislodged calcific foci'''
***[[File:Nephrocalcinosis.jpg|alt=Nephrocalcinosis. Source: Wikipedia|thumb|Plain film x-ray demonstrating bilateral diffuse calcium deposits in the kidneys. Source: [[commons:File:Nephrocalcinosis.jpg|Wikipedia]]]]'''Causes[https://radiopaedia.org/articles/medullary-nephrocalcinosis §]'''
***[[File:Nephrocalcinosis.jpg|alt=Nephrocalcinosis. Source: Wikipedia|thumb|Plain film x-ray demonstrating bilateral diffuse calcium deposits in the kidneys. Source: [[commons:File:Nephrocalcinosis.jpg|Wikipedia]]|400x400px]]'''Causes[https://radiopaedia.org/articles/medullary-nephrocalcinosis §]'''
****'''Medulla'''
****'''Medulla'''
*****'''Type 1 (distal) RTA'''
*****'''Type 1 (distal) RTA'''
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*'''Imaging'''
*'''Imaging'''


=== '''Management''' ===
=== Management ===
*'''Renal colic pain management[https://smhs.gwu.edu/urgentmatters/content/alternatives-opioids-pain-management-ed]'''
*'''Renal colic pain management[https://smhs.gwu.edu/urgentmatters/content/alternatives-opioids-pain-management-ed]'''
** '''Toradol 30 mg IV'''
** '''Toradol 30 mg IV'''
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== Diet Therapies ==
== Diet Therapies ==
* '''<span style="color:#ff0000">General diet therapies to reduce risk of stone recurrence (6)'''
* '''<span style="color:#ff0000">General diet therapies to reduce risk of stone recurrence (6)'''
*# '''<span style="color:#ff0000">Increase fluid intake'''
*# '''<span style="color:#ff0000">Increase fluid intake (urine volume of > 2.5 liters daily)'''
*# '''<span style="color:#ff0000">Limit sodium intake'''
*# '''<span style="color:#ff0000">Limit sodium intake (≤100 mEq (2,300 mg) per day)'''
*# '''<span style="color:#ff0000">Moderate calcium intake'''
*# '''<span style="color:#ff0000">Moderate calcium intake (1,000-1,200 mg per day)'''
*# '''<span style="color:#ff0000">Limit intake of oxalate-rich foods'''
*# '''<span style="color:#ff0000">Limit intake of oxalate-rich foods'''
*# '''<span style="color:#ff0000">Increase intake of fruits and vegetables'''
*# '''<span style="color:#ff0000">Increase intake of fruits and vegetables'''
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*# '''Promotes excretion of sodium causing extracellular volume depletion'''
*# '''Promotes excretion of sodium causing extracellular volume depletion'''
*#* '''Long-term thiazide therapy results in volume depletion, extracellular volume contraction, and proximal tubular resorption of sodium and calcium.'''
*#* '''Long-term thiazide therapy results in volume depletion, extracellular volume contraction, and proximal tubular resorption of sodium and calcium.'''
* '''Drugs and dosages'''
* '''<span style="color:#ff0000">Drugs and dosages'''
**'''Hydrochlorothiazide (50mg orally, once daily;''' 25mg orally, twice daily''')'''
*#'''<span style="color:#ff0000">Hydrochlorothiazide</span> (50mg orally, once daily;''' 25mg orally, twice daily''')'''
**'''Chlorthalidone (25mg orally, once daily)'''
*#'''<span style="color:#ff0000">Chlorthalidone</span>''' (25mg orally, once daily)
**Indapamide (2.5mg orally, once daily)
*#'''<span style="color:#ff0000">Indapamide</span> (2.5mg orally, once daily)'''
**Chlorthalidone (25-50 mg/day) or indapamide (2.5 mg/day) are preferred to hydrochlorothiazide since they are long-acting and are once a day dosing.
*#*Chlorthalidone or indapamide are preferred to hydrochlorothiazide since they are long-acting and are once a day dosing.
*** Indapamide is technically not a thiazide but does share a successful hypocalciuric effect with the other agents.
*#* Indapamide is technically not a thiazide but does share a successful hypocalciuric effect with the other agents.
* '''Patients placed on thiazide diuretics for management of hypercalciuria should also be placed on dietary sodium restriction'''
* '''<span style="color:#ff0000">Patients placed on thiazide diuretics for management of hypercalciuria should also be placed on dietary sodium restriction'''
** '''An excess sodium load will inhibit reabsorption of calcium in the proximal tubule, thereby causing hypercalciuria.'''
** '''An excess sodium load will inhibit reabsorption of calcium in the proximal tubule, thereby causing hypercalciuria.'''
* '''<span style="color:#ff0000">Adverse events'''
* '''<span style="color:#ff0000">Adverse events'''
** '''<span style="color:#ff0000">Lassitude and sleepiness'''
** '''<span style="color:#ff0000">Sleepiness and lassitude'''
*** '''<span style="color:#ff0000">Most common side effects of thiazides'''
*** '''<span style="color:#ff0000">Most common side effects of thiazides'''
*** Can occur in the absence of hypokalemia
*** Can occur in the absence of hypokalemia
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**# '''<span style="color:#ff0000">Hypocitraturia'''
**# '''<span style="color:#ff0000">Hypocitraturia'''
**# '''<span style="color:#ff0000">Metabolic alkalosis'''
**# '''<span style="color:#ff0000">Metabolic alkalosis'''
**'''Hypocitraturia'''
**'''<span style="color:#ff0000">Hypokalemia and glucose intolerance'''
***'''Result of hypokalemia with intracellular acidosis'''
**'''<span style="color:#ff0000">Hypokalemia and hyperglycemia'''
*** '''The degree of diuretic-induced hypokalemia correlates with level of hyperglycemia.'''
*** '''The degree of diuretic-induced hypokalemia correlates with level of hyperglycemia.'''
**** Mechanism: hypokalemia impairs insulin secretion, thereby increasing plasma glucose.
**** Mechanism: hypokalemia impairs insulin secretion, thereby increasing plasma glucose.
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****'''The addition of amiloride or spironolactone may avoid the need for potassium supplementation'''.
****'''The addition of amiloride or spironolactone may avoid the need for potassium supplementation'''.
****Triamterene, although it is potassium-sparing, should be avoided as stones of this compound have been reported
****Triamterene, although it is potassium-sparing, should be avoided as stones of this compound have been reported
**'''Hypocitraturia'''
***'''Result of hypokalemia with intracellular acidosis'''
**'''Patients with undiagnosed primary hyperparathyroidism may develop hypercalcemia after initiation of thiazide therapy'''
**'''Patients with undiagnosed primary hyperparathyroidism may develop hypercalcemia after initiation of thiazide therapy'''
*** Although most patients with primary hyperparathyroidism demonstrate hypercalcemia and hypercalciuria, a normal serum calcium level in the presence of an inappropriately high serum PTH value may be seen in some cases, making the diagnosis more difficult. Administration of a thiazide diuretic will enhance renal calcium reabsorption and exacerbate the hypercalcemia, thereby facilitating the diagnosis (“thiazide challenge”)
*** Although most patients with primary hyperparathyroidism demonstrate hypercalcemia and hypercalciuria, a normal serum calcium level in the presence of an inappropriately high serum PTH value may be seen in some cases, making the diagnosis more difficult. Administration of a thiazide diuretic will enhance renal calcium reabsorption and exacerbate the hypercalcemia, thereby facilitating the diagnosis (“thiazide challenge”)
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**#**'''Patient's treated with sodium alkali will occasionally begin forming calcium oxalate stones due to an excess sodium load that will inhibit reabsorption of calcium in the proximal tubule, thereby causing hypercalciuria'''
**#**'''Patient's treated with sodium alkali will occasionally begin forming calcium oxalate stones due to an excess sodium load that will inhibit reabsorption of calcium in the proximal tubule, thereby causing hypercalciuria'''
**#**'''If the patient is at risk for hyperkalemia, other agents such as sodium bicarbonate or sodium citrate should be considered.'''
**#**'''If the patient is at risk for hyperkalemia, other agents such as sodium bicarbonate or sodium citrate should be considered.'''
*'''<span style="color:#ff0000">Adverse Events (2)</span>'''
**'''<span style="color:#ff0000">Hyperkalemia</span>'''
**'''<span style="color:#ff0000">GI upset</span>'''


===Recurrent calcium stones===
===Recurrent calcium stones===
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**'''<span style="color:#ff0000">Allopurinol should not be routinely offered as first-line therapy to patients with uric acid stones</span>'''
**'''<span style="color:#ff0000">Allopurinol should not be routinely offered as first-line therapy to patients with uric acid stones</span>'''
***'''Most patients with uric acid stones have low urinary pH rather than hyperuricosuria as the predominant risk factor'''
***'''Most patients with uric acid stones have low urinary pH rather than hyperuricosuria as the predominant risk factor'''
***'''Goal is to increase the urinary pH > 5.5 (AUA targets 6.0 and CUA targets 6.5), through an alkalinizing agent such as potassium citrate'''
***'''<span style="color:#ff0000">Goal is to increase the urinary pH > 5.5 (AUA targets 6.0 and CUA targets 6.5), through an alkalinizing agent such as potassium citrate'''
**** With adequate alkali therapy, patient's can raise the urine pH to an optimal level so that uric acid remains in a dissolved state.
**** With adequate alkali therapy, patient's can raise the urine pH to an optimal level so that uric acid remains in a dissolved state.
***** '''Attempts at alkalinizing the urine to a pH > 7.0 should be avoided. At a higher pH, there is a danger of increasing the risk for calcium phosphate stone formation.'''
***** '''<span style="color:#ff0000">Attempts at alkalinizing the urine to a pH > 7.0 should be avoided. At a higher pH, there is a danger of increasing the risk for calcium phosphate stone formation.'''
***Patients may initially present with low/normal 24-hour urinary uric acid levels because the uric acid will precipitate out of solution in the acid urinary environment. Once the urine has been alkalized, all of the uric acid will come back into solution, causing a significant increase in the measured urinary uric acid.
***Patients may initially present with low/normal 24-hour urinary uric acid levels because the uric acid will precipitate out of solution in the acid urinary environment. Once the urine has been alkalized, all of the uric acid will come back into solution, causing a significant increase in the measured urinary uric acid.
*'''<span style="color:#ff0000">Allopurinol may be considered as an adjunct when alkalinization is not successful or for patients who continue to form uric acid stones despite adequate alkalinization of the urine.</span>'''
*'''<span style="color:#ff0000">Allopurinol may be considered as an adjunct when alkalinization is not successful or for patients who continue to form uric acid stones despite adequate alkalinization of the urine.</span>'''
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** Acetazolamide, a carbonic anhydrase inhibitor, leads to an increase in urinary bicarbonate and increased H+ reabsorption.
** Acetazolamide, a carbonic anhydrase inhibitor, leads to an increase in urinary bicarbonate and increased H+ reabsorption.
** Up to 50% of patients may discontinue acetazolamide due to adverse effects.
** Up to 50% of patients may discontinue acetazolamide due to adverse effects.
===Uric acid and cystine stones===
===Uric acid and cystine stones===
* '''<span style="color:#ff0000">Potassium citrate should be offered to patients with uric acid and cystine stones to raise urinary pH to an optimal level</span>'''
* '''<span style="color:#ff0000">Potassium citrate should be offered to patients with uric acid and cystine stones to raise urinary pH to an optimal level</span>'''
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**** '''Pyridoxine (vitamin B6) deficiency supplementation is recommended'''
**** '''Pyridoxine (vitamin B6) deficiency supplementation is recommended'''
===Infection/Struvite stones===
===Infection/Struvite stones===
*'''The preferred management of struvite calculi involves aggressive surgical approaches'''
*'''<span style="color:#ff0000">The preferred management of struvite calculi involves aggressive surgical approaches'''
**'''The medical management of infection calculi centers on the prevention of recurrence, rather than medical dissolution.'''
**'''The medical management of infection calculi centers on the prevention of recurrence, rather than medical dissolution.'''
*'''<span style="color:#ff0000">Acetohydroxamic acid (AHA) may be offered to patients with residual or recurrent struvite stones only after surgical options have been exhausted.</span>'''
*'''<span style="color:#ff0000">Acetohydroxamic acid (AHA) may be offered to patients with residual or recurrent struvite stones only after surgical options have been exhausted.</span>'''
** '''Patients treated for struvite stones may still be at risk for recurrent UTIs after stone removal, and in some patients surgical stone removal is not feasible.'''
** '''Patients treated for struvite stones may still be at risk for recurrent UTIs after stone removal, and in some patients surgical stone removal is not feasible.'''
**'''The use of a urease inhibitor, AHA, may be beneficial in these patients, although the extensive side effect profile may limit its use. In particular, patients taking this medication should be closely monitored for phlebitis and hypercoagulable phenomena'''
**'''The use of a urease inhibitor, AHA, may be beneficial in these patients, although the extensive side effect profile may limit its use. In particular, patients taking this medication should be closely monitored for phlebitis and hypercoagulable phenomena'''
**'''Acetohydroxamic acid (AHA)'''
**'''<span style="color:#ff0000">Acetohydroxamic acid (AHA)'''
*** '''MOA: urease inhibitor; may reduce the urinary saturation of struvite and therefore delay stone formation'''
*** '''MOA: urease inhibitor; may reduce the urinary saturation of struvite and therefore delay stone formation'''
*** '''Adverse effects'''
*** '''<span style="color:#ff0000">Adverse effects'''
**** Minor side effects common (up to 30% of patients)
**** Minor side effects common (up to 30% of patients)
**** '''Deep venous thrombosis''' (15%)
**** '''<span style="color:#ff0000">Deep venous thrombosis</span>''' (15%)
**** '''Hemolytic anemia'''
**** '''<span style="color:#ff0000">Hemolytic anemia'''
***** '''Most serious side effect'''
***** '''Most serious side effect'''
***** '''Occurs in up to 15% of the patients; more prevalent in patients with renal insufficiency'''
***** '''Occurs in up to 15% of the patients; more prevalent in patients with renal insufficiency'''
****'''<span style="color:#ff0000">Phlebitis'''
*** '''Frequently reserved for patients deemed too ill for surgical management.'''
*** '''Frequently reserved for patients deemed too ill for surgical management.'''
*Long-standing effective control of infection with urea-splitting organisms should be achieved if at all possible with improved bladder health, adequate urinary drainage, and suppressive antibiotics
*Long-standing effective control of infection with urea-splitting organisms should be achieved if at all possible with improved bladder health, adequate urinary drainage, and suppressive antibiotics
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** '''An effective, first-line therapy for mild-moderate hypercalciuria'''
** '''An effective, first-line therapy for mild-moderate hypercalciuria'''
*** Thought to have a protective role in preventing nephrolithiasis by decreasing urinary calcium and oxalate excretion through alteration of prostaglandin metabolism
*** Thought to have a protective role in preventing nephrolithiasis by decreasing urinary calcium and oxalate excretion through alteration of prostaglandin metabolism
* '''Hyperparathyroidism complicated by stone disease is best treated with surgical excision of the adenoma'''
* '''Hyperparathyroidism complicated by stone disease'''
**'''Best treated with surgical excision of the adenoma'''


* '''Enteric hyperoxaluria'''
* '''Enteric hyperoxaluria'''
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* There is a lack of consensus regarding normal laboratory values during 24-hour urine collections in children. Clinicians have relied on ratios to correct for the wide variation of weight
* There is a lack of consensus regarding normal laboratory values during 24-hour urine collections in children. Clinicians have relied on ratios to correct for the wide variation of weight
* '''The medical management of nephrolithiasis and the prevention of subsequent recurrences in children do not differ that dramatically from the approaches undertaken for adults'''
* '''The medical management of nephrolithiasis and the prevention of subsequent recurrences in children do not differ that dramatically from the approaches undertaken for adults'''
== Follow-up==
== Follow-up==
*'''<span style="color:#ff0000">Labs</span>'''
*'''<span style="color:#ff0000">Labs</span>'''
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== Questions ==
== Questions ==


# What is the risk of stone recurrence at 10 years in first-time stone formers?
# What are lifestyle changes a patient could make to reduce risk of stone recurrence?
# What is the microscopic appearance of common urinary calculi?
#What are side effects related to thiazides?


== Answers ==
== Answers ==
1. 50%
 
#What are lifestyle changes a patient could make to reduce risk of stone recurrence?
#What are side effects related to thiazides?


== Next Chapter: [[Stones: Surgical Modalities for Management of Upper Urinary Tract Calculi|Surgical Modalities for Management of Upper Urinary Tract Calculi]] ==
== Next Chapter: [[Stones: Surgical Modalities for Management of Upper Urinary Tract Calculi|Surgical Modalities for Management of Upper Urinary Tract Calculi]] ==
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