Unrelieved obstruction leads to
hydronephrosis (dilation of renal pelvises and calyces) and obstructive uropathy-->progressive atrophy of kidney due to obstruction of urine outflow
Pathophysiology of hydronephrosis
Complete obstruction leads to filtrate returning back to perirenal and institial spaces (eventually back to lymph and venous systems)
Continued filtrated causes calyces and pelvises to become dilated; this high pressure is transmitted back through the collecting duct and into the cortex, leading to renal atrophy.
Compression of renal medullary vasculature also leads to less plasma flow and medullary functional disturbance, with impaired concentrating ability at first, eventually lowering GFR later.
Also causes interstitial inflammation and fibrosis
Morphology of hydronephrosis
slight to massive enlargement of kidneys, with progressive blunting of pyramid apices.
Chronic cases lead to cortical tubular atrophy with diffuse interstitial fibrosis
Advanced cases: thin-walled cystic kidneys, parenchymal atrophy, no pyramids, thin cortex
4 types of urolithiasis
1. calcium containing stones (calcium oxalate, calcium phosphate)--radio-opaque; hypercalcemia, hypercalciuria, hyperoxaluria
2. triple or struvite stones (magnesium ammonium phsophate)
3. uric acid stones--radiolucent
4. cystine stones--defect in renal reabsorption of AA (cystine)
What is hyperoxaluria?
increase oxalate in urine, usually caused by vegeterian diet; accounts for 5% of calcium stones
How are struvite stones formed?
following infection with urea-splitting bacteria (Ureasplasma urealytica, Proteus); the alkaline urine causes precipitation of these large stones (staghorn calculi)
Uric acid stones common in what two types of patients
2. diseases with rapid cell turnover (e.g. leukemia)
Favored sites of urolithiasis
renal calyces, pelvises, and bladder
Which are worse--smaller or larger stones?
smaller, b/c pass into ureters and cause colic and ureteral obstruction
larger stones cannot enter ureters and cause hematuria
What enhances stone formation in the urine?
deficiency in inhibitors of crystal formation in urine
4 congential anomalies of the ureter
1. double and bifid ureters (from double or split ureteral bud)
2. ureteropelvic junction obstruction: abnormal organization of smooth muscle or excess stromal deposition of collagen leads to hydronephrosis
3. diverticula of ureteral wall
4. hydroureter--dilation, elongation, and tortuosity of ureter
2 morphological classifications of ureteritis
Aggregation of lymphocytes in the subepithelial region
1. ureteritis follicularis--fine granular mucosal surface
2. ureteritis cystica--mucosa sprinkled with fine cysts aggregating to form grape-like clusters
3 types of tumors and tumor-like lesions of the ureter
Primary neoplasia is rare
2. fibroepithelial polyp--loose, vascularized connective tissue mass
3. transitional cell carcinoma causing obstruction
Five categories of intrinsic obstructive lesions of the ureter
3. tumors of the ureter
4. blood clots
4 categories of extrinsic obstructive lesions of the ureter
2. periureteral inflammation
4. tumors (rectum, bladder, prostate, ovaries, uterus, etc)
What is sclerosing retroperitoneal fibrosis?
fibrous proliferative inflammatory process encasing retroperitoneal structures leading to hydronephrosis. May be associated with chronic inflammatory process.
5 types of congenital anomalies of the urinary bladder
1. diverticula--often acquired with prostate enlargement increasing intravesical pressure
2. exstrophy--developmental failure in ant abd wall and bladder (increase adenocarcinoma risk)
3. Vesicoureteral reflux: most common
4. Congenital vesicouterine fistula--communication b/w bladder and vagina or uterus
5. patent urachus--bladder connected to umbilicus, increasing risk of urachal cysts and adenocarcinoma
4 bacteria responsible for cystitis
E.coli, Proteus, Klebsiella, Enterobacter
What pathogen found in Egypt and Sudan causes chronic cystitis? What cancer does it increase the risk of?
squamous cell carcinoma of bladder
Risk factors for developing hemorrhagic cystitis
Describe follicular cystitis
aggregation of lymphocytes into lymphoid follicles within the bladder mucosa
Describe eosinophil cystitis
eosinophils infiltrate the submucosa; indication of a systemic allergic d/o or nonspecific subacute inflammation
Describe polypoid cystitis
inflammation due to irritation to bladder mucosa (e.g. cath insertion), causing submucosal edema that sends the transitional epithelium into polypoid projections
Describe interstitial cystitis
fissures and punctate hemorrhages in the bladder mucosa with transmural fibrosis and contracted bladder
What are Hunner's ulcers?
ulceration on wall of bladder associated with interstitial cystitis
Interstitial cystitis is associated with what types of dz?
autoimmune dz (like SLE)
soft raised mucosal plaques with large foamy macrophages and multinucleated giant cells
What are Michaelis-Gutmann bodies?
calcium deposition in enlarged lysosomes associated with malakoplakia
Malacoplakia is associated with what disease state?
Bacterial infection (E.coli, Proteus) and impaired macrophage function