Changes In Outflow: Incontinence and Obstruction Flashcards
What occurs during the initial phase of unilateral urethral obstruction?
Urine backflow:
- Increase in intraluminal hydrostatic pressure
- Compensatory afferent arteriolar dilation and increase in GFR –> increasing glomerular capillary pressure to fight the increased intraluminal hydrostatic pressure
- eventual activation of RAAS leading to second phase
What occurs during the second phase of unilateral ureteral obstruction?
after 6+ hours unilateral ureteral obstruction is complete
this is due to RAAS activation causing afferent arteriole vasoconstriction
What is the third phase in unilateral ureteral obstruction?
- decreased luminal hydrostatic pressure below baseline
- decreased renal blood flow below baseline
What occur with unilateral ureteral obstructions lasting more than 24 hours?
can cause a 50% drop in GFR
How does Bilateral ureteral obstruction vary from unilateral ureteral obstruction?
bilateral ureteral obstruction has only two phases
Initial Phase - same as in unilateral
- urine backflow –> compensatory increase in GFR –> eventual RAAS activation
Second phase (6+ hours after obstruction)
- decrease in glomerular blood flow due to afferent arteriolar vasoconstriction
- GFR maintained (no explanation, may be ANP influence)
what does unilateral/bilateral ureteral obstruction lead to?
tubular dysfunction
Describe the tubular dysfunction seen in unilateral ureteral obstruction
inability to reabsorb sodium
- salt wasting
- kidney that is working will excrete more urine higher in [sodium]
Describe the tubular dysfunction seen in bilateral ureteral obstruction
volume expansion within the body because fluid cannot be excreted at all
- hyperkalemia - there are high [K+] in the lumen, but due to low-flow luminal state K+ can’t get out
- associated with RTA Type 1 (tubular defect)
What occurs with RBF, GFR, and other hemodynamic effects in Acute Kidney Outlet Obstruction
- Increased RBF
- Decreased GFR
- Decreased medullary blood flow
- Increased vasodilation (Prostaglandins, NO)
What occurs with RBF, GFR, and other hemodynamic effects in Chronic Kidney Outlet Obstruction
- Decreased RBF
- Significantly decreased GFR
- Increased vasoconstriction (prostaglandins)
- Increased RAAS production
What triad do patients with urinary tract obstruction present with?
- azotemia
- hyperkalemia
- metabolic acidosis
what is the most common inherited anomaly of the GU tract effecting males more then females?
vesicoureteral reflux
(can lead to needing a kidney transplant)
slow stream, increase urgency, dribbling after finishing, incomplete emptying, and nocturia (leading to sleep deprivation)
BPH (Benign Prostatic Hypertrophy)
What occurs over time with BPH?
incomplete emptying –> stretch of bladder wall/muscle –> permenant ineffecive bladder contraction (incontinence, overflow incontinence)
How do we diagnose someone with incomplete emptying of the bladder and probable overflow incontinence?
have pt void
determine volume using US, if > 100 mL (positive)
What are the common causes of neurogenic bladder (inability to relax sphincter)?
- SC trauma
- spinal myelomningocele
- spinal stenosis
- herniated discs
What is renal liathiasis?
caused by a kidney stone that produces a characteristic pain pattern to the lower back and groin
What is postobstructive diuresis?
occurs after a BUO
flow is restored, but the kidneys aren’t doing their job yet and are just diuresing
a result of downregulation of Na+ transporters during obstruction
patient may produce up to 750 mL/h of urine
differentiate urgency, stress, and overflow incontinence
Urgency incontinence - sudden urgent need to urinate
Stress incontinence - loss of bladder control while laughing/exertion
Overflow incontinence - can’t urinate when you want even though you feel like you have to, dribbles.
- urine pH 6
- sodium: 140 mmol/L
- potassium: 5.5 mmol/L
- chloride: 135 mmol/L
- CO2 15 mmol/L
urine pH > 5.5
NAG (10)
potassium elevated (3.5 - 5.1 mmol/L)
generalized tubular defect, ureteral obstruction
What are the causes of chronic tubulointerstitial disease?
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- Prostate (obstructive uropathy)
- Analgesics (NSAIDs)
- VU reflex
- Lead (heavy metals)
- Gout
- Myeloma
What are the characterizations of Chronic Tubulointerstitial Disease?
- Isothenuria w/ polyuria
- moderate proteinuria
- very few cells
- Type I, II, or IV RTA
- Broad waxy casts
- small kidneys
Describe the results of a digital rectal exam for patient with prostitis
- Boggy
- Tender
- Slightly enlarged
Describe findings from a digital rectal exam for prostatic cancer
- Asymmetrically enlarged
- firm
