Intrinsic obstruction of the UT can occur from ?
stones, clotted blood, sloughed cells, or transitional neoplasms
Extrinsic obstructions can occur from?
pregnancy, tumors, or inflammatory conditions including fibrosis
The most common points of intrinsic obstruction are?
the renal pelvis, uteropelvic junction and the urethra
(1) disease is much more likely to present acutely whereas (2) disease can be difficult to diagnose because the other kidney can functionally compensate
Congenital anomalies which can produce an obstruction
posterior urethral valves (often found in young males) along with urethral strictures, bladder neck obstruction and ureteropelvic junction narrowing
A number of intrinsic tumors can produce obstruction including?
transitional carcinomas of bladder, ureter or renal pelvis or renal cell carcinoma
Extrinsic tumors such as (1) can also produce obstruction
prostate cancer or cervical cancer
Inflammatory disorders such as (1) can cause obstruction, as can neurological diseases, including (2)
prostatitis, urethritis and ureteritis spinal cord injury and autonomic dysfunction due to diabetes or other causes
Obstruction in the more distal parts of the urinary tract produces back pressure that will ultimately?
Initially, there is continued filtration even with complete obstruction, but this eventually leads to loss of filtration, so there is usually less (1) or dilation of the collecting system as a consequence of (2) than there is from (3)
1. hydronephrosis 2. complete obstruction 3. partial or intermittent obstruction
Sudden, complete renal obstruction often causes (1) which can help lead to the diagnosis
capsular distension and acute pain
Sudden bilateral obstruction leads to (1), and (2) which can be readily diagnosed and treated
1. oliguria (low urine output) 2. renal failure
Bilateral partial obstruction can lead to impaired renal function with impaired (1) which will be observed as (2)
1. concentrating ability 2. frequency and nocturia and renal hypertension
After removal of the obstruction there is usually a (1) which produces a large volume of urine flow. However if the obstruction continues, there is eventually (2), which is not reversible
1. post-obstructive diuresis 2. large cystic dilation of the kidney with atrophic cortex
Early in the course of obstruction, there is elevated pressure and decreased renal medullary blood flow that initially produces (1). For this reason, the initial injury causes a decrease in (2)
1. tubular damage 2. renal concentrating ability.
Microscopically in hydronephrosis there is dilation of the (1) which progresses to dilation of (2) and eventual tubule loss. (3) are generally spared until fairly late in the course of the disease.
1. collecting ducts 2. proximal and distal convoluted tubules 3. Glomeruli
There is usually LESS hydronephrosis or dilation of the collecting system in ____ than ______
complete obstruction; partial obstruction
Intrinsic obstruction causes in adults:
Urinary calculi (renal or ureter stones) Strictures (caused by STD’s).
Intrinsic obstruction causes in elderly
Post-operative stones—if the ureter is compromised
•Men: ____ and ____
•Females: GYN malignancy (carcinoma of the cervix or uterus).
Both: ___ and ____
BPH, Prostate cancer;
retroperitoneal pelvic malignancy (retroperitoneal lymphoma); bladder tumors
Extrinsic obstruction can be caused by:
•Pregnancy-->Physiologic response leads to ____—usually on the ___ side);
ureteral dilatation; right
•Far-advanced cases of obstruction:
What does it cause? (1)
What does this look like grossly? (2)
(1) causes very large cystic-looking kidneys.**not reversible*
(2)Thin-walled cystic structure; 15-20 cm diameter; Loss of pyramids;Thin cortex
____ obstruction (aka acute obstruction) produces pain from ____ distention
SUDDEN COMPLETE; renal capsule
____has pain receptors--> acute flank pain in the back area if acute aka sudden obstruction
partial bilateral vs. complete bilateral symptoms
Partial --> Impaired renal concentration; therefore POLYURIA and nocturia
Complete--> Renal function markedly diminished therefore OLIGURIA or ANURIA and renal failure; INCOMPATIBLE w/ survival.
Dilatation of the collecting system—renal pelvis and calyces—within the kidney (if in ureter--> hydroureter)
Pathophysiology of hydronephrosis:
- Filtration and thus ___ continues (even w/ complete obstruction) and then Filtrate diffuses back to ___ and ___ (into lymphatics and venous systems).
- With time, the BACK PRESSURE leads to:
____: high back pressure hits the cortex, affecting the proximal tubular function (bigger effect on tubular function) and then glomerular function.
GFR; interstitium of kidney; perirenal spaces;
Renal atrophy; inner medullary blood flow;
•Functional loss over time:
- ____ first --> impaired concentrating ability; ↑ DILUTE urine
- ____ are initially spared; late in the course see glomerular disease, AND THUS decreased GFR
•TUBULAR effects first in hydronephrosis--> what would you see?
impaired concentrating ability; ↑DILUTE urine
•Obstruction causes interstitial inflammatory rxn LEADING TO ____ causing further injury
Grossly: Dilatation is ___ to obstruction
First--> Dilation of ___;
Then--> Dilation of ____
Finally--> ___ become widely dilated leading to ____
Distal convoluted tubule (some proximal also)
Finally--> proximal convoluted tubule; tubule loss;
Frequency, dysuria, urgency, hesitancy, and hematuria
complication of hyronephrosis: ___ of the urine can lead to infection caused by bacteria