Urinary System Part 2 Flashcards
Urinary Tract Obstruction
-A urinary tract obstruction is defined as a blockage of urine flow with the urinary tract
-The obstruction can be caused by an anatomic or functional defect
Obstructive uropathy
Severity based on:
-Location
-Completeness
-Involvement of one or both upper urinary tracts
-Duration
-Cause
Urinary Tract Obstruction- Complete
- Hydroureter-dilation of ureter proximal to site of blockage
- Hydronephrosis-dilation of the renal pelvis and calyces proximal to site of blockage
Urinary Tract Obstruction- Complete
Within 2 days:
- Tubulointerstitial fibrosis- deposition of excessive amounts extracellular matrix (collagen and other proteins)
- Apoptosis- excess cell destruction and death
- Partial function restored within 56-69 days if obstruction removed.
Strategies for recovery renal function after urinary tract obstruction:
-Compensatory hypertrophy of healthy tissue
- Obligatory growth-Somatostatin
-Compensatory growth- unknown hormones -Postobstructive diuresis -Low bladder wall compliance -Inability to accommodate urine at low pressures due to excessive deposition of extracellular matrix in bladder wall and detrusor muscle
Urinary tract obstruction:
-Individuals at risk for hypertension -RAA cascade is elevated -Individuals at risk for Urinary tract infections -Incomplete bladder empty -Urine turbulance in the urethra
Upper Urinary tract obstruction: Kidney stones
- Calculi or urinary stones
Masses of crystals, protein, or other substances that form within and may obstruct the urinary tract
-Risk factors
Gender, race, geographic location, seasonal factors, fluid intake, diet, and occupation
-Kidney stones are classified according to the minerals comprising the stones
Kidney Stones - 3 factors required:
1) Supersaturation of one or more salts
-Presence of a salt in a higher concentration than the volume able to dissolve the salt
2) Precipitation of a salt from liquid to solid state
- Temperature and pH
3) Growth into a stone via crystallization or aggregation
Temperature and pH
- Temperature usually constant so not usually a factor
- Acidic urine pH- increase risk uric acid stone
- Alkaline urine pH- increase risk of calcium phosphate stone
Kidney Stones
-Other endogenous factors affecting stone formation
Crystal growth-inhibiting substances
Particle retention
Matrix- organic material contained in urinary calculus
- Stones
Calcium oxalate or calcium phosphate
Struvite stones
Cystinuric stones-genetic disorder amino acid metabolism
Uric acid stones
Indinavir- Rx protease inhibitor for HIV
Calcium Oxalate or Calcium Phosphate Stones:
-80% of stones
-Idiopathic calcium urolithiasis (ICU)
Unknown cause, but usually one or more of the following
-Hypercalciuria
-Hyperoxaluria
-Hyperuricosuria
-Hypocitraturia
-Mild renal tubular
acidosis
-Crystal growth
inhibitor deficiencies
Hypercalcinuria:
Can be associated with -Intestinal hyper- absorption of dietary calcium -Hyperthyroidism - Bone demineralization caused by prolonged immobilization
Struvite Stones
- Magnesium-ammonium-phosphate
- Large amounts of matrix
- Associated with Urinary tract infection
Kidney Stones:
Manifestation- principle symptom - Renal colic Evaluation - Stone analysis - Intravenous pyelogram - Spiral abdominal CT Treatment -Stone removal
Renal Colic
- Moderate to intense pain
- If stone in lower tract could have symptoms of urgency, frequent voiding, or urge incontinence
Lower Urinary Tract Obstruction:
- Bladder neck dyssynergia
–Smooth muscle urethrovesical junction fails to funnel during micturation and obstructs the bladder outlet - Prostate enlargement
Lower Urinary Tract Obstruction:
-Urethral stricture --- Scar narrowing urethral lumen --- Infection, surgery -Severe pelvic organ prolapse --Cystocele blocks the bladder outlet