Nephrolithiasis Flashcards
Consequences
Renal pelvis dilation
Hydronephrosis
Potential for infection
Chronic compression and eventual ESRF
pelvic stones are usually symptomless
Types of stones.
Calcium
Struvite
Uric acid
Cysteine
Types of calcium stones
Ca-Oxalate,
Ca-Oxalate-Phosphate
Struvite stones composition and causes
Treatment
Mg-Ammonium-Phosphate
MAP
Causes by Basic/Alkaline urine, usually from infection with a urease positive microbe. P. vulgaris,
Rx: treat microbe, surgical stone removal
Uric acid stones physical description and cause
Treatment
Small, yellow, round stones
Radiolucent
Causes:
Acidic urine, plus
Hyperuricemia, gout,
Allopurinol or fubuxostat
Hydration and alkalinization of urine
Cysteine stones composition and cause
Treatment
Rare,
occurs in children
due to cystinuria, genetic defect of impaired cysteine resorption.
acidic urine also favors cysteine stone formation
Rx:
1) Captopril, Tiopronin, Penicillamine, bind urinary cysteine and make it more soluble
2) Alkalinize urine, and improve hydration.
Causes of calcium stones:
Hypercalcemic-Hypercalciuric
-any disorder causing hypercalcemia, most commony HyperPTHims
Normocalcemic-Hypercalceuric
- Familial type, decreased calcium resorption from the tubules, aka Renal hypercalciuria
Hyperoxaluria type
- Seen mostly in vegetarians,
Treatment for calcium stones
1) Thiazide diuretics, plus K+ and Mg++ supplementation to comepnsate
2) Citrate supplementation, inhibits calcium crystal formaion
3) Pyridoxine for primary hyperoxaluria
Thiazide diuretics decrease epethelial intracellular Na+ concentration, and
thereby increase activity of the basolateral Na+/Ca++ antiporter, which transports Ca to the renal interstitium, overall increasing Ca resorption.
Workup/diagnostic tests for kidney stones
Urine pH
Urine culture before antibiotics
Serum creatinine Serum CRP Serum Ca++ Serum Uric acid Serum phosphate
24 hour cystine excretion
24 hr urate excretion
Dietary treatment and prevention of stones
Good hydration,
Urinate 2-2.5 liters/day
Avoid acidic drinks, coke, grapefruit
Maintain normal Ca++ intake
Decrease salt, oxalate, and purine intake
Protein intake <150g/day
