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
immobilizationStruvite 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 removalRenal 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
Lower Urinary Tract Obstruction:
-Neurogenic bladder dysfunction
-Leads to urinary incontinence or retention
Pathophysiology
-Neurogenic detrusor overactivity
– Uncontrolled or premature contractions
–Detrusor sphincter dyssynergia
-Obstruction- detrusor sphinctor dyssynergia
- Low bladder wall compliance
Neurogenic Bladder Tumors:
-Renal tumors
Renal adenomas
Renal cell carcinoma
-Bladder tumors
Papillary tumors
Nonpapillary tumors
Metastasis to lymph
nodes, liver, bone,
and lungsUrinary Tract Infection:
- UTI is inflammation of the urinary epithelium following invasion and colonization by some pathogen within the urinary tract
- Complicated UTI- comorbid to other disorders urinary tract
- Uncomplicated UTI – no other problems
- Persistent UTI- ongoing despite treatment
Urinary Tract Infection:
-Most common pathogens
Escherichia coli
Staphylococcus
saprophyticus
Enterobacter spp
Virulence of uropathogens-Strategies to survive
- Host defense
mechanisms
-- Urine pH, urea,
periurethral
mucous-secreting
glands
Urinary Tract Infection:
Cystitis
- Cystitis is an
inflammation of the bladder
-Manifestations
Frequency, dysuria, urgency, and lower abdominal and/or suprapubic pain
Treatment
-Antimicrobial therapy, increased fluid intake, avoidance of bladder irritants, and urinary analgesics
Urinary Tract Infection:
-Pyelonephritis
—Acute pyelonephritis
-Acute infection of the ureter, renal pelvis, and/or renal parenchyma
—Chronic pyelonephritis
-Persistent or recurring
episodes of acute
pyelonephritis
-Risk of chronic
pyelonephritis
increases in individuals
with renal infections
and some type of
obstructive pathologic
condition
Glomerular Disorders:
-The glomerulopathies are disorders that directly affect the glomerulus
-Urinary sediment changes
- Nephrotic sediment
(Proteinuria, lipiduria,
little or no hematuria)
-Nephritic sediment
(Hematuria, RBC casts,
White blood cells,
proteinuria)
-Sediment of chronic
glomerular disease
(Waxy casts, granular
casts, less prot. or hem).
What is cast?
- “mass comprised of fibrous material, coagulated protein, or exudate that takes the shape of the region in which it has been molded, such as bronchial, renal, or intestinal structures and is usually found in urine or sputum.”
- McCance Glossary
Glomerular Disorders
-Glomerular disease demonstrates a sudden or insidious onset of hypertension, edema, and an elevated blood urea nitrogen (BUN)
- Decreased glomerular filtration rate
–Elevated plasma creatinine, urea, and reduced creatinine clearance
-Glomerular damage causes a decreased glomerular membrane surface area, glomerular capillary blood flow, and blood hydrostatic pressure
Glomerular Disorders:
- Increased glomerular capillary permeability and loss of negative ionic charge barrier result in passage of plasma proteins into the urine
-Resulting hypoalbuminemia encourages plasma fluid to move into the interstitial spaces
–Edema
Glomerular Disorders
-Glomerulonephritis
Inflammation of the
glomerulus
-Immunologic
abnormalities (most
common)
-Drugs or toxins
-Vascular disorders
-Systemic diseases
- Viral causesGlomerulonephritis
-Mechanisms of injury
-Deposition of circulating soluble antigen-antibody complexes, often with complement fragments
-Formation of antibodies against the glomerular basement membrane
-Streptococcal release of neuramidase
Glomerulonephritis- Types
- Acute poststreptococcal glomerulonephritis
- IgA nephropathy (Berger disease)
- Crescentic glomerulonephritis
- Antiglomerular basement membrane disease (Goodpasture syndrome)-Chronic glomerulonephritis
- cause, pathologic lesions, disease progression, clinical presentation
Nephrotic Syndrome
-Excretion of 3.5 g or more of protein in the urine per day
-The protein excretion is due to glomerular injury
-Findings
Hypoalbuminemia, edema, hyperlipidemia, and lipiduria
Nephrotic Syndrome
-Membranous glomerulonephritis
–Most common idiopathic nephrotic syndrome in whites; assoc. with hyperlipidemia and hyppercoaguability
-Focal and segmental glomerulosclerosis
–Most common id Neur Syn in blacks.
Minimal change disease (lipoid nephrosis)
–Most common in children
Nephrotic Syndrome- Pathophysiology
-Renal Dysfunction- Classifications
Renal insufficiency
< 10% function
Renal Dysfunction: Classifications
Uremia
-Syndrome renal failure with elevated blood urea and creatinine, fatigue, nausea, vomit, pruritis, neurologic changes.
-Retention of nitrogenous toxic wastes, deficiency states, electrolyte disorders
Renal Dysfunction: Classifications
Azotemia
-Increased serum urea levels and creatinine levels, nitrogenous wastes
Acute Renal Failure
-Acute- within hours
-Prerenal acute renal failure
–Most common cause
of ARF
–Caused by impaired
renal blood flow
–GFR declines due to
the decrease in
filtration pressure
Acute Renal Failure (ARF):
- Intrarenal acute renal failure
Acute tubular necrosis (ATN) is the most common cause of intrarenal renal failure
–Postischemic
–Nephrotoxic
- Postrenal acute renal failure
Occurs with urinary tract obstructions that affect the kidneys bilaterally
Acute Renal Failure:
Oliguria: urine output less than 30ml/hr or less than 400ml/day
Acute Renal Failure:
- initiation phase
- maintenance phase
- Recovery phase
Chronic Renal failure:
-Chronic renal failure is the irreversible loss of renal function that affects nearly all organ systems
-Progression
Reduced renal reserve
Renal insufficiency
Renal failure
End-stage renal disease
Chronic Renal Failure:
Alterations in electrolyte and acid-base balance
- Creatinine and urea clearance
- Sodium and water balance
- Phosphate and calcium balance
- Potassium balance
- Acid-base balance
Chronic Renal Failure:
- Skeletal and bone alterations
- Cardiopulmonary system
- Neural function
- Endocrine and reproduction
- Hematologic alterations
Chronic Renal Failure:
- Immunologic
- Gastrointestinal
- Integument
- Alterations in proteins, carbohydrates, and lipids
