Kidney Stones Flashcards
What are three forms of Urinary Tract Crystallization?
- Nephrolithiasis/Urolithiasis - stone forming disorders/drugs
- Nephrocalcinosis - medullary sponge kidney
- Bladder Stones - bladder dysfunction
Medullary sponge kidney is associated with malformation of the _____ tubules
distal
What are some key factors associated with the etiology of stone formation?
- Urinary supersaturation
- Crystal retention at the renal papilla
- Associated risk factors
What are the most common compositions of kidney stones?
Which requires a predisposing factor to form?
Mostly calcium oxalate
30% have calcium phosphate
Urates are third most common
Struvite next most common - Requires urea secreting bacteria to form
WHat are some demographic associations with kidney stones?
- Men> women (about 2:1 although has decreased recently)
- White race more commonly affected
- Peak incidence in middle age
- Substantial regional variations
Lifetime prevalence of kidney stones = __-__%
Recurrence rates exceed __% in 5 years
5-15%
50%
Is the prevalence of kidney stones increasing or decreasing?
Increasing
What drugs can form stones?
Indinavir
Acyclovir
Triamterene
Sulfamethoxazole
What are some genetic diseases causing stones?
Cystinuria - L-cystine
Primary hyperoxalosis - calcium oxalate
Dent Disease - calcium oxalate or calcium phsophate
Describe L-Cystine stone disease
Transporter system for recovering L-Cystine is defective - build up forms heagonal plates
What are the three types and two possible defective genes associated with L-Cystine stone disease and what is their prevalence?
-
Type A (38%) - SLC 3A1 - Recessive, targeting protein
- Proximal tubule - high affinity and low capacity
-
Type B (47%) - SLC7A9 - incompletely dominant, transporter
- Proximal tubule - Low affinity and high capacity
- Type AB (14%)
Primary hyperoxalosis/hyperoxaluria is a rare genetic disorder which leads to excessive synthesis of ______ ______
endogenous oxalate
What are the 3 known gene defects associated with primary hyperoxalosis and what do they cause?
- PH1 - 80% - alanine-glyoxylate aminotransferase (AGXT) defect
- PH2 - 10% - glycoxylate reductase/hydroxy pyruvate reductase (GRHPR) defect
- PH3 - 10% - 4-hydroxy-2-oxaloglutarate aldolase (HOGA1) defect
Why can calcium oxalate easily cause supersaturation in kidney?
Solubility of calcium oxalate in water is very low
As urine volume increases, relative supersaturation for calcium oxalate _______
decreases
What are some diet risk factors associated with hyperoxaluria?
- Low fluid intake
- High salt intake
- High protein intake
- Low calcium intake
- High oxalate intake
Increasing calcium in the diet ______ risk of Kkidney stones
decreases
How do kidney stones present on physical exam?
- Distress
- Fever
- Hematuria
- Elevated WBCs
- Elevated serum creatinine
- Nausea, vomiting
What are the two best diagnostic tools for kidney stones?
CT scan (best)
Ultrasound
What can inhibit all stone types?
What inhibits calcium stones specifically?
Citrate inhibits all
Magnesium inhibits calcium stones
What is the most common urinary abnormality in calcium oxalate stone formers?
Low urine volume
How are kidney stones treated?
Removal of stone
Symptom control
What are acute treatments to stone formation?
- Noninvasive
- pain control and fluids
- Medical expulsive therapy
- Dissolution therapy
- Extra-corporeal shock wave lithotripsy (ESWL)
- Uretoscopy
- Percutaneous approach
- Surgery
What are some chronic treatments to stone formation?
- Dilution
- Alkalinize urine
- Cystine binding drugs (disulfide exchange)
How do you treat uric acid crystals?
- Dilution
- low protein diet
- alkalinize urine
- Xanthine oxidase inhibitors
- Allopurinol
- Febuxostat
How do you treat struvite crystals?
- Dilution
- Sterilize urine (eliminate bacteria)
- Remove residual stone material (surgical)
- Adjunctive therapies
How do you treat calcium stones?
- Dilution
- Maintain normal calcium intake
- Reduce urine calcium exretions
- Reduce urine oxalate
- Increase urine citrate
High water intake _____ stone recurrence rates
decreases
High protein intake _____ calcium excretion in the urine
increases
Increased duration of treatment with thiazide diuretics corresponds to ______ stone recurrence compared to placebo
decreased
