Nephrolithiasis Flashcards
What is nephrolithiasis? What are the risk factors that induce it?
Precipitation of any of the urinary solutes as a stone. High urine solute concentration in urinary filtrate and low urine volume will increase risk.
What is the classic presentation of nephrolithiasis?
Colicky pain with hematuria and unilateral flank tenderness.
How many different types of nephrolithiasis are there and which are the most common?
Calcium oxalate or phosphate is the most common type, and there are 4 general types: calcium oxalate/phosphate, ammonium/Mg/phosphate, uric acid, cysteine, in that order of frequency.
What is the most common cause of calcium oxalate/phosphate stones? What are other causes?
Most common cause is idiopathic hypercalciuria, where there is increased calcium in the urine but blood Ca levels are fine. Other causes includes hypercalcemia and its related causes. Also Crohn’s disease.
How is calcium oxalate/phosphate stones treated?
Via hydrochlorothiazide, a calcium sparing diuretic (where you pee a lot and try to flush out the stone in the urine).
What causes the ammonium/magnesium/phosphate kidney stones?
Most commonly infections with urase positive organisms, like proteus or klebsiella. The urase will alkalinize the urine and the alkaline urine leads to the formation of the stone.
In what kind of kidney stone do we see the “staghorn calculi” and why is this especially problematic? How is it treated?
In the ammonium/Mg/phosphate induced stones, this staghorn calculi is a nidus for other bacteria to grow and thus leads to UTI’s. These are huge so surgical exicision is needed and the bacteria that caused this needs to be killed. Also cysteinuria can cause staghorn calculi.
Which kind of kidney stones are radio opaque and radioluscent?
Uric acid stones are radioluscent, all others are radio opaque (so you can see it in an x-ray).
Risk factors that cause uric acid stones?
Hot dry climates which encourages low urine volume and acidic pH. Patients with gout have increased risk, patients with hyperuricemia due to leukemia and myeloproliferative disorders have increased risk.
How are patients with uric acid kidney stones treated?
Alkalinazation of the urine with potassium bicarb and hydration. Allopurinol is given to patients with gout.
What causes the cysteine kidney stones?
Rare genetic disease seen in children. Seen in cysteinuria, which is a genetic disorder of the kidney tubules, where cysteine has decreased reabsorption.
What kind of stones are formed in cysteine kidney stones? How is it treated?
Staghorn calculi can be formed. Hydration and alkalation of urine is a tx option, if staghorn then surgery.
