Stones Flashcards
Why do infants on furosemide develop stones?
Hypercalciuria causing nephrocalcinosis
Tx. change to thiazide
When do you perform 24 hour urinary analysis?
Recurrent stone formers
if patient wants
all kids or high risk patients
What is the pathophysiology of Cystinuria:?
inadequate resorption of cystine, ornithine, lysine, arginine (COLA) in proximal tubule
How do you diagnose Cystinuric stones?
Sodium Nitroprusside
How do you treat Cystinuric stones?
- 1) K citrate, high fluid intake (3-4L/day), low salt/protein,
- 2) Thiola (alpha mercaptopropionyl) or D-penicillamine if (1) fails
- 3) Captopril if unable to tolerate (2)
What genetic marker is associated with cystinuria?
SLC
What is the pathophysiology of Ammonium Acid stones:?
Protein deficiency -> Phosphate deficiency -> high urinary ammonium levels
How do you diagnose Ammonium acid stones?
phenolphthalein
What conditions are associated with Uric acid stones?
Diabetes (defective ammonium excretion)
Chemo/rads for leukemia/lymphoma (cell lysis)
Ileostomy (acidosis from bicarb loss)
Lesch Nyan/gout
What is the pH of Uric Acid stones
< 5.5
How do you treat Uric Acid stones?
potassium citrate
allopurinol (if hyperurecemia ex. leukemia, Lesch Nyan)
What is the difference between brushite and apatite shones?
Both calcium phosphate
brushite pH < 6.6
apatite pH > 6.6
What condition is associated with calcium phosphate brushite stones?
hyperparathyroidism
What type of stone is struvite?
calcium phosphate apatite
magnesium ammonium phosphate
What type of organisms are associated with struvite stones?
Urease splitting (proteus, klebsiella, pseudomonas, staphylococcus)
What are Randall’s plaques made of?
Calcium apatite
What is the pathophysiology of Hyperoxaluria Type 1
disorder of glyoxalate metabolism (AGT deficiency)
What is the treatment of Hyperoxaluria Type 1?
B6, K citrate
Liver/kidney transplant
What are some causes of hyperoxaluria?
short gut syndrome
chronic antibiotics
When do you treat calcium oxalate stones with allopurinol?
Isolated hyperuricosuria
What type of stones are formed from RTA Type I
calcium phosphate
What is the pathophysiology of RTA type I?
Impaired acidification of distal tubule
What are the urine characteristics of RTA Type 1 stone formers?
urinary alkaline, hypercalciuria, Hypocitrauria (<50)
What should be considered in stone formers with hypomagnesuria?
Underlying bowel disease
