OBSTRUCTIVE UROPATHYStructural & functional with normal urine flow along the urinary tract, from renal tubule to the urethra.The resultant increased pressure , proximal to the obstruction hydronephrosis, dilatation of calyxes & renal pelvis anatomic outcome that affect collecting system, distal to the renal pelvis.Hydroureter, often accompany hydronephrosis, if obstruction is distal to the ureteropevic junction

In USA 400,000 px hospitalized Hydronephrosis : 3 % with men & women , equalStrictures of urethra & ureter, causes of obst. at autopsy in px of 10 yrs or women : 20 30 yrs of age Hereditary : inborn errors of metabolism 4 main types of calculi : * 70% Ca, Ca Oxalat or Ca OX + Ca Phos. * 15% Triple stone * 5 10 % uric acid * 1 2% cystine

Stone formation : increased urinary concentration of stone constituents,exceeds their solubility in urine ( supersaturation )Ca Oxalat stone : 5% of px with hypercalcemia & hypercalciuria ( caused by hyperparathyroid, bone disease, sarcoidosis ) 20% Ca Ox, stone associated with incr, uric acid secr)Mg Am Ph. Stone, formed after infection by urea splitting bacteria(e,g, Proteus ), which convert urea to ammoniaprecipitationstaghorn calculi

Uric acid stone : Common in px with hyperuremia > 50% have neither hyperurecemia nor increased urinary excr, of uric acid.Cystine stone, caused by genetic defect in the renal re-abs, of amino acid, incl. cystin cystinuria; formed at low pHStone formation depends on : pH, decreased urine vol, & infection