Kidney Stones - NACE Flashcards
(55 cards)
What is the lifetime risk of getting a kidney stone?
10% of people will get a kidney stone in their lifetime
T or F: by the age of 70 women are twice as likely as men to get a kidney stone.
False, women are HALF as likely as men to get kidney stones
After getting a kidney stone, what is the recurrence risk of it coming back?
- 5% per year recurrence risk (1/20 ppl who have had a kidney stone will get another one within the next year)
- This is a high rate of Recurrence
What factors effect the concentration of solutes that may precipitate in the urine causing stones?
Amt of Solute:
• Filtered Load
• Tubular Secretion
• Tubular Reabsorption
Vol. of Solvent:
• Salt and Water Balance
What are the 4 types of solute that account for the majority of stones?
- Calcium Salts (75%)
- Stuvite (15%)
- Uric Acid (10%)
- Cysteine
What causes Cystinuria?
• how common is this?
• Epidemiology?
• Why must we catch this?
Cystinuria = GENETIC disorder of reabsorption in the Tubules
How Common/Epidemiology?
• Found in 1-2% of ADULT stones
• 5% of stones in CHILDREN
Why worry?
• Can cause LOSS of kidney function if left untreated
T or F: urine pH can provide a major clue to the type of stone that is likely to form in someone’s urine
True, pH is a MAJOR TARGET for INTERVENTIONS to prevent recurrent stones
Why are natural inhibitors so important?
Because the urine is typically supersaturated with solutes that comprise stones
Where is Tamm-Horsfall mucoprotein located and what would happen if you inhibited its formation?
Tamm-Horsfall is made in the THICK ASCENDING LOOP OF HENLE.
• it BINDS solutes, so preventing its formation would LEAD SO STONE FORMATION
T or F: presence of a foreign body in the kidney of ANY type will increase the propensity to form stones.
TRUE, calcium stone may from around Uric Acid or even Nanobacteria
*This is just seeding a cystalization
What is the utility of looking at crystals in the urine of a normal person?
• what about someone with a stone?
- NO utility in looking at stones in a normal person who doesn’t have stone
- IN someone WITH a stone, the crystals in the urine may tell you about COMPOSITION of the stone
Where are stones most likely to form?
• why is this?
Stones = most likely to form in the LOW URINE FLOW areas
- CALYCES and PELVIS are therefore the most common places to see stone formation
- stasis and stone formation is also the reason you can see bladder stones
T or F: stones are more likely to form in areas of obstruction.
True
What are the 2 subtypes of Calcium stones formed?
• which is more common?
• How does urine pH affect each of these?
2 types:
• Calcium Oxalate (60%) - INDEPENEDENT of pH
• Calcium Phosphate (15%) - FORMS STONES IN ALKALINE ENVIRONMENT
What are some drugs known to cause kidney stones?
- Indinavir
- Triamterene
- Acyclovir
- Sulfadiazine
Explain the ways that Ca2+ may increase in concentration leading to stone formation?
Increased Filtered Load:
=> Exogenous - inc. intake
=> Endogenous - inc. PTH, Vit. D. Sarcoid, Ideopathic
Decreased Renal Reabsorption:
• EXCESS DIETARY Na+
• Pharmacologic => LOOP diuretics
Decreased Urine Volume
Besides Ca2+, the concentration of what other substance is important to the formation of Ca2+ stones?
Oxalate, remember this forms stones indepedently of pH
Oxalate
• how is its concentration increased?
INCREASE filtered Load (ONLY): Exogenous: • Dietary XS • Low Ca2+ diet • bowel pathology
Endogenous:
• Increased Production
How can you treat Calcium Oxalate Crystals that are caused by too much Ca2+?
Reduce Ca2+:
• avoid Ca2+ supplement BUT DO NOT RESTRICT DIETARY Ca2+
• Potassium Citrate +/- allopurinol
Reduce Na+:
• THIAZIDE DIURETICS
• SODIUM RESTICTION
Dilute:
• Adequate Fluids
• Less Animal Protein, and Salt
also look for any underlying causes of hypercalcemia
What type of stones do you have a fairly high risk of getting with type I RTA?
• CaP, because this type of RTA PREVENTS ACIDIFICATION in the DISTAL TUBULE
= More Basic Environment and Decreases Citrate concentration
What is the more common cause of Uric Acid Kidney Stone formation: underexcretion or overproduction?
• exceptions?
Underexcretion = most common cause
• Ppl. with GOUT tend to OVERPRODUCE uric acid so both factors contribute to stone formation
Contrast the formation of CaP, Uric Acid, and Struvite stones.
CaP stones - form in a BASIC environment
Stuvite stones - form in a BASIC environment
Cysteine Stone - from in ACIDIC environment
Uric Acid stones - form in ACIDIC environment
What recommendations and prescriptions should be written to prevent Uric Acid crystal formation in patients.
Dietary Modifications:
• Increase Fluids
• Less Animal Protein
• Less EtOH
Drug Treatments:
• Allopurinol
• Potassium Citrate
When is the ONLY time you see Stuvite Stones forming?
- Presence of Increased Urinary NH4+ concentration and Alkaline pH
- this ONLY occurs with UTI with urease-producing organism (proteus, Serratia, Klebsiella, Mycoplasma)
