Stones Flashcards
1 year recurrence rate after 1st stone
10-15%
5 year recurrence rate after 1st stone
50-60%
10 year recurrence rate after 1st stone
70-80%
Initial work-up for new stone former
Dietary History (fluids, meat, calcium) Medical History (DM, gout, obesity, bowel surgery, RTA, parathyroid) BMP UA Urine Culture
What medications increase stone risk?
Topiramate Zonisamide Acetazolamide Triamterene Probenecid Protease Inhibitors (-navir) Vitamin C
If serum calcium is high, next lab?
PTH
1 risk factor for uric acid stones
low urine pH
1 risk factor for struvite stones
recurrent UTIs
Radiolucent stones
uric acid & cystine
Indications for 24hr urine
Interested 1st time stone formers
Recurrent stone formers
Initial dietary recommendations for ALL stone formers
>2.5L fluid intake daily Na & oxalate restriction Normal calcium intake (1000-1200mg/day) Decrease animal protein Increase citrus intake
Increased sodium intake leads to _____ in urinary calcium excretion
increase
Excess urinary ____ blocks hypocalciuric action of thiazies
sodium
Consumption of ____ enhances GI binding of Oxalate and decreased oxaluria
calcium
Clinicians should counsel patients with CaOx stones & hyperoxaluria to limit ____ rich food intake and maintain normal ___ consumption
limit oxalate rich foods
normal calcium consumptions
Congenital, primary hyperoxaluria is due to a ____ deficiency. Only treatment option is ____
hepatic enzyme (alanine aminotransferase)
renal & liver transplant
Enteric hyperoxaluria is due to ____ malabsorption leading to limited calcium to bind to oxalate
fat
Clinicians should encourage patients with Calcium stones & hypocitraturia to increase intake of ____ & limit intake of ____
increase fruits & veggies
limit animal protein
1st line therapy for hypercalciuria and recurrent stones
Thiazide diuretics
Thiazide diuretics work at the _____ to promote calcium resorption
Distal renal tubule
20% RR in stone formation
Side effects of thiazides
Hypokalemia
Hypocitraturia
High urine uric acid
Supplement thiazides with ___ to overcome hypokalemia
Potassium Citrate 40-60 mEq daily
1st line therapy for low urinary citrate and recurrent calcium stones
Potassium citrate
- alkalizes urine
- promotes citrate excretion
Citrate reduces stone formation by inhibiting ____
crystallization of calcium salts
RTA - low ___ levels in serum and low ___ levels in urine
Hypokalemia
Hypocitraturia
Young female with calcium phosphate stones, nephrocalcinosis, urine pH >6.5, hypocitraturia, hypokalemia
Distal RTA
35 yo M with calcium oxalate stones, acidic urine, hypocalciruia, and hypocitraturia, and prior bowel surgery
Enteric hyperoxaluria
Contraindications to K Citrate
Hyperkalemia
Active gastric ulcer
Cr > 2.5
Cheaper alternative to K Citrate
Na Bicarbonate
Urine pH in uric acid stone formers
pH < 5.5
Obese patients have an independent increased risk of ___ stones
Uric acide
Offer ____ to patients with uric acid or cystine stones to raise urinary pH
K Citrate
To dissolve cystine stones, urine pH must be above ____
pH 7.5
Pharmaceutical therapy for struvite stones
Acetohydroxamuc acid (Lithostat)
Before PCNL, one must obtain ____
PCNL
ESWL contraindicated with skin to stone distance >___cm
10 cm
Alpha-blockers can be offered for patients with ureteral stones
10mm
Treatment for enteric hyperoxaluria
Oral Calcium & Mg
How to address thiazide-induced hypocitraturia?
Add potassium citrate
Contraindications to Potassium Citrate
____ Potassium
Active ____ disease
Cr > ____
High K
Active peptic ulcer disease
Cr >2
Uric Acid stones
pH < ____
pH < 5.5
UA with cystinuria - ____ Crystals
Hexagonal
Cystine stones rapidly dissolve at pH > ___
pH > 7.5
Urease producing bacteria
SHP
Staph Aureus
Hemophilus Influenza
Proteus
Obtain a repeat 24 hour after ____ of initiating pharmaceutical treatment
6 months
Optimal imaging prior to PCNL is a ____
CT A/P non-contrast
ESWL parameters
Hounsfield units < ____
Skin to stone distance
<1000 HU
<10 cm
If hydronephrosis or cortical thinning is seen on imaging, obtain ____ lab test
Cr, BUN, electrolytes aka BMP
____ should be offered after 1 month trial of MET or suspicious of stone passage
Repeat imaging (KUB, RBUS, or CT)
SWL has the ____ complication rate, but the ____ stone free rate
lowest….. worst
1st line treatment for mid & distal ureteral stones - ____
URS
Only proven therapy to reduce stent discomfort is ____
alpha-blocker
Only proven therapy to reduce stent discomfort is ____
alpha-blocker
In Symptomatic Patients With A Total Renal Stone Burden >20 mm, Clinicians Should Offer____ As First- line Therapy
PCNL
May Offer ___ or ____ to Patients With Symptomatic <10 mm Lower Pole Renal Stones
ESWL or URS
Pts With Lower Pole Stones >10 Mm Should Be Informed That ____ Has A Higher Stone-free Rate But Greater Morbidity
PCNL
____ should Not Be Offered As First-line Therapy To Pts With >10mm Lower Pole Stones
ESWL
In the absence of a UTI, SWL does not require ____
peri-op antibiotics
Prescribe ____ to facilitate stone passage after ESWL
alpha-blockers
If ESWL fails, next therapy should be ____
URS
____ is 1st line in patients on anti-platelet or anti-coag
URS
