229- urinary obstruction Flashcards
blood supply direction to ureter
proximal to iliac arteries it comes from medial side. Distally it comes from lateral side
what happens in phase 2 of acute obstruction
pressure is going up while flow is going down
how long before irreversible damage is done? what does this mean clinically?
Full recovery possible up until seven days. After 6 weeks no recovery is possible. Give the patient one week to pass stone on their own
limit for diuretic renography
if it takes longer to clear than 20 min there is an obstruction
limit for whitaker test
pressure gradient greater than 22 cm means obstruction
What is post-obstructive diuresis? when is ti a problem?
polyuria following bilateral obstruction clearance. Start to worry if urine output is >200ml/hr for 2 hrs and urine osmolality is low.
Replace with D5 half NS at .5ml for every 1ml lost
four most common types of stones in order
calcium oxalate and calcium phosphate, Ammonium magnesuim phosphate (struvite or infection), uric acid, cysteine
which type of stone is seen in kids? Which is radiolucent? which are associated with infection and with what kind of bacteria? which is associated with crohns disease?
cysteine
uric acid
Ammonium magnesium phosphate (struvite); urease+ bacteria such as proteus vulgaris, klebsiella)
calcium oxalate/calcium phosphate
what is the most common cause of calcium stones? treatment?
hypercalciuria plus/minus hypercalcemia. Thiazide diuretics. Limit high-oxalate foods like nuts vegetables, etc
What type of stone form staghorn calculi? treatment?
in adults: struvite. Tx large and nidus for infection so surgical removal and eradicate pathogen.
In kids: cystein. Tx is hydration and alkalinization of urine with potassium citrate and thiola
Uric acid stones: risk factors? associated conditions?
gout, increased purine consumption (red meats). High turnover of nucleic acids as in leukemia or myeloproliferative disorder. Tx is low purine diet and alkalinize urine with potassium bicarb
