stone disease Flashcards
what are most stones made out of?
CA
what stones are radioopaque?
Ca
most important factors for urinary stone development?
high protein,
high salt
inadequate hydration
acidic urine makes what kind of stones?
uric acid or cystine stones
alkaline urine produces stones how?
contributes to UTI prodoucing (proteus, klebsiella) making struvite stones
what is the MC stone?
calcium oxalate stones
what is the strongest promoter of stone formation?
urinary oxalate
what are the two causes of increased oxalate?
not enough calicium in the gut or >2 g/day ascorbic acid (vit C)
what helps prevent calcium phosphate and calcium oxalate crystallization?
increased urinary citrate that binds w/ calcium and doesnt allow stone formation. there is more citrate in alkalotic urine
what are risks for calcium oxalate and calcium phosphate stones?
high sodium, high animal protein diet, dehydration, hypercalciuria, low urine citrate
what causes struvite stones?
MC women w/ recurrent URIs w/ urease producing bacteria
what are struvite stones?
magnesium-ammonium-phosphate stone
what are urease-producing bacteria?
proteus, pseudomonas, providencia, klebsiella, staphylococcus, and mycolplasma
what is the acidity for calcium oxalate stones?
> 7.2
what risk does calcium phosphate have that calcium oxalate does not?
increased urine alkalinity
stone frequently composed of struvite that’s in the renal pelvis and extends into at least 2 calyces
staghorn calculi
what is the only amino acid insoluble in urine?
cystine
what pH do cystine and uric acid stones form in?
pH <5.5
what stones are radioopaque?
struvite
calcium
what stones are radiolucent?
cystine
uric acid stones
what increases the risk of uric acid stones?
think people that have malignancy or are undergoing malignancy treatment
myeloproliferative disorders
clinical findings of stones?
colic pain: obstructing
sudden (may awaken from sleep) severe, unremitting flank pain \+/- N/V constantly moving around looking for comfort hematuria CVA tenderness pain may refer as it moves down ureter
if the stone is lodged at the ureterovesical junction what are the symptoms?
marked urinary urgency and frequency
what pH will you see calcium phophate stones?
> 7.5
what is the gold standard imaging for stones?
non contrast CT
What imaging for stones if the patient is pregnant?
Renal US
What is the “standard of care” imaging for stones for a pregnant woman?
Non-contrast CT
Asymptomatic stone treatment w/ no signs of infection?
Nothing
What size stones will pass spontaneously?
<= 5-6 mm
What is acute treatment for stones?
Hydration: oral first then IV
Medications: analgesics (NSAID, but be careful because if they are taking an ACEI in scenario it will be evident that it is safe to use an NSAID if not then use narcotics), anti-emetic, alpha blocker
What patients would you refer for stones?
Infection (bacteremia, sepsis) Obstruction Intractable pain (admit and control)
N/V Stone size >=6mm Fails to pass w/in 4 weeks Pregnant Immunocompromised Fail to pass in 4 weeks
Who gets emergent urologic evaulation and drainage?
Obstructive urinary calculi w/ fever and infected urine
What works well on stones in the renal pelvis or upper 2/3 of ureter and size <1.5 cm?
Extracorporeal Shock wave lithotripsy: DISCONTINUE NSAIDS 3 DAYS PRIOR BECAUSE OF BLEEDING
What can be placed following ESWL to facilitate passage of stones?
Ureteral stent
What is good for stone removal in lower 1/3 of ureter?
Ureteroscopic stone extraction
What is good for stones in renal collecting system, upper 2/3 of ureter, and >2cm?
Percutaneous nephrolithotomy
What can be used to remove stones in patients w/
1. Complex anatomy
2. Obstruction
3. Large infected struvite stones?
I think he said stag horn or pregnant in review?
Open stone surgery
When is imaging maybe unnecessary for stones?
Recurrent
What is the bottom line treatment for acute stone treatment?
Fluids
Pain control
Confirm stone
Admit (failure to control pain, infection, comorbidity)
Refer: (infection, large stone, comorbidity)
What are the labs for recurrent stones?
24 hr. Urine collection assess:
- total volume
- pH
- Urinary excretion of Ca, oxalate, citrate, sodium potassium and creatinine
Serum PTH, Uric acid r/o primary hyperparathyroidism or gout
What are prevention measures for stones?
Decrease salt
Decrease animal product
DO NOT RESTRICT CA
increase Bran and water
Avoid soda (high phosphate)
Avoid Vit C (ascorbic acid metabolism- inc. oxalate)
Decrease dietary oxalate
Treatment for recurrent stones?
If high calcium Thiazide diuretics (HCTZ, chlorthalidone)
If low urinary citrate or low urine pH
Potassium citrate therapy
Citrate inc for Ca
Raise pH in uric acid or cystine stone formers
How much should a patient urinate daily?
1.5-2 L/day
What is the f/u for stones?
Chronic:
Repeat 24 hr urine in 6 months
Repeat stone analysis if interventions are failing
Consider yearly CT to assess for new formation
