Urinary patho 2014
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Transcript of Urinary patho 2014
The Urinary System
Kidney functions Other system organs
General system anatomy
Kidney str & fxn Nephron – basic fxnal
unit of the kidney
Overview
Kidney Functions Filter 200L blood/day to eliminate:
Toxins Metabolic wastes Excess ions
Regulate blood volume ~ 5 L
Regulate chemical makeup of the blood 300 mmoL concentration of solutes (i.e. sodium,
potassium, zinc) Maintain the proper balance between H20 & salts,
and acids and bases.
Other Kidney Functions Gluconeogenesis
Production of renin
Production of erythropoietin
Activation of vitamin D
Other Urinary System Organs
Urinary bladder – provides temp. storage reservoir for urine
Paired ureters – transport urine from the kidneys to the bladder
Urethra – transports urine from the bladder out of the body
Ureters Slender tubes-carry urine: kidneys to the bladder Ureters enter the base of the bladder through the
posterior wall As bladder pressure increases (increased urine
volume in bladder), distal ends of ureters get closed off & prevent backflow of urine into ureters.
Tri-layered wall Epithelial mucosa Smooth muscle Fibrous connective tissue
Ureters actively propel urine to the bladder via response to smooth muscle stretch
Urinary Bladder Smooth, collapsible, muscular sac that temporarily
stores urine
Lies on the pelvic floor posterior to the pubic symphysis
Males – prostate gland surrounds the neck inferiorly
Females – anterior to the vagina and uterus
Trigone – triangular area outlined by the openings for
the ureters and the urethra
Clinically important because infections tend to persist
in this region
Urinary Bladder The bladder wall has three layers
epithelium
muscular layer
fibrous layer
The bladder is distensible &
collapses when empty
As urine accumulates, the bladder expands without
significant rise in internal pressure
Bladder Cancer 60,000 cases a year in the US
13,000 deaths per year 4 times more likely to occur in men Most frequently b/w 60-70 yrs of age
Causes ? Environmental exposures
High rates in employees in chemical and rubber plants
Prognosis for metastatic bladder cancer is poor Spreads to bone, lymphatic system
Tissue engineering: Bladder
Bladder disease
Increased pressure in poorly functioning bladder
leads to kidney damage
Reconstruction w/ small intestine tissue
Grow own bladder cells in culture for 7-8 weeks
Attached ‘new bladder’ to old bladder in 7, 4-19 yr old
children
2-5 yrs later: improved bladder function in all
subjects
Urethra Muscular tube that:
Drains urine from the bladder Moves urine out of the body
Sphincters keep the urethra closed when urine is not
being passed
Internal sphincter – involuntary sphincter at the
bladder-urethra junction
External sphincter – voluntary sphincter surrounding
the urethra as it passes through the urogenital
diaphragm
Levator ani muscle – voluntary urethral sphincter
The female urethra is tightly bound to the anterior
vaginal wall
External opening lies anterior to vaginal opening and
posterior to the clitoris
The male urethra has 3 named regions:
Prostatic urethra – runs within the prostate gland
Membranous urethra – runs through the urogenital
diaphragm
Spongy (penile) urethra – passes through the penis
and opens via the external urethral orifice
Prostate Gland Surrounds Urethra
Prostate Gland: Size of walnut
Surrounds neck of urinary
bladder and urethra
Secretes fluid that forms part
of semen
Benign Prostate Disorders Infection Inflammation Enlarged prostate
High blood levels of PSA Impotence Incontinence and or retention
S&S of prostate disorders Interference of flow Change in urinary freq. urination Pain
Prostate CA
Increased likelihood with enlarged prostate
(hypertrophy).
60% of prostate cancers discovered remain localized
5 yr survival = 100%
10 yr survival = 68%
15 yr survival = 52%
In past 20 yrs survival has increased from 67-93%
Other Considerations PSA check annually after age 50 High risk males should begin screening
earlier Risk factors
Age Race
African Americans are 61% more likely to get prostate CA & 2.5x more likely to die from dx
Diet: high fat / low fiber Obesity Environmental exposures
Kidney Location & Structure Bean-shaped
extends from T-12 to L-3. R kidney hangs lower than left.
crowded by the liver
Layers of Tissue Support Renal capsule – fibrous capsule surrounding kidneys
that gives support & helps prevent infection
Adipose capsule – fatty mass that cushions the kidney
and helps attach it to the body wall
Renal fascia – outer layer of dense fibrous connective
tissue that anchors the kidney
Internal Structure of Kidney Cortex – the light colored, granular superficial region
Medulla – exhibits cone-shaped medullary (renal)
pyramids
Pyramids are made up of parallel bundles of urine-
collecting tubules
Renal columns are inward extensions of cortical tissue
that separate the pyramids
Pyramid plus its surrounding capsule, constitute a
lobe
Large blood flow to kidney:~25% (1200 ml) of BF from heart into
systemic circulation, flows through the kidneys per minute.
The Nephron Nephrons: stral & fxnal units of the kidneys that form
urine: Glomerulus: a capillary bed associated with a renal
tubule Bowman’s capsule: cup-shaped end of a renal tubule
that surrounds glomerulus. Renal corpuscle – the glomerulus and its Bowman’s
capsule Glomerular endothelium –epithelium that allows
solute-rich, virtually protein-free filtrate to pass from the blood into the glomerular capsule
Renal Tubule Proximal convoluted tubule (PCT):
Composed of cuboidal cells with numerous microvilli
and mitochondria
Reabsorbs water and solutes from filtrate and
secretes substances into it
Loop of Henle: a hairpin-shaped loop of the renal tubule
Distal convoluted tubule (DCT):
cuboidal cells w/o microvilli that function more in
secretion than reabsorption
Nephrons Cortical nephrons – 85% of nephrons; located in the
cortex
Juxtamedullary nephrons:
Located at the cortex-medulla jxn
Have loops of Henle that deeply invade the medulla
Have extensive thin segments
Are involved in the production of concentrated urine
Capillary Beds of the Nephron
B/P in the glomerulus is high:
Kidney is very well vascularized
High density of blood vessels
Blood flow within nephron controlled by afferent
arteriole
Fluids & solutes are forced out of the blood
throughout the entire length of the glomerulus
Characteristics of Normal Urine• Complex watery (95%) solution of organic &
inorganic wastes (5%)• Color: pale, straw to amber color
– If highly concentrated:
•Hematuria / orange color–‘milky’ / turbid : infection
• Clarity: transparent• Odor: faintly aromatic; will change to ammonia
if standing too long. Some drugs and vegetables (asparagus) alter the usual odor
• pH: 5.5 – 7.0– Will turn alkaline if left standing
Characteristics of Normal Urine Specific Gravity:
Indicates concentration of urine (# of particles in it) Normal values = 1.01 – 1.03
Measured by comparing the weight of pure water vs. urine
Urine should not contain: Albumin Glucose Ketones Blood / Pus / Bacteria Calculi Bile
Normal Output
Normal voiding: 250 – 500cc
Normal 24 hour voiding: 1000
- 1500cc
Normal hourly: 30 -120cc
< 30cc / hr may indicate renal
pathology
Chemical Composition of Urine Urine is 95% water and 5% solutes
Nitrogenous wastes include urea, uric acid, and
creatinine
Other normal solutes include:
Na+, K+, phosphate, and sulfate ions
Calcium, magnesium, and bicarbonate ions
Abnormally high concentrations of any urinary
constituents may indicate pathology
Trauma, Ischemia & Kidney Damage Ischemia – decreased oxygen supply to nephron because
there is decrease in blood flow
Decreased blood flow to nephron which is chronic can
lead to Kidney Damage.
Anything that causes afferent arteriole prolonged
constriction
Renal Clearance Diagnostic Test The volume of plasma that is cleared of a particular
substance in a given time Clearance tests are used to:
Determine the GFR Detect glomerular damage Follow progress of renal dx
Renal Clearance
RCR = UV/P
RCR = renal clearance rate
U = concentration (mg/ml) of the substance in urine
V = flow rate of urine formation (ml/min)
P = concentration of the same substance in plasma
Urinary Disorders: S&S Changes in urinary frequency
or volume
Dark urine
Pain with urination
Kidneys unable to regulate
body H2O & Na+ balance
Edema (fluid retention) &
or High B/P
Urinary Tract Patho Urinalysis
General health of urinary sys Drug testing
Proteinuria Glomerular damage
Ketonuria Diabetes or starvation
Glucosuria Diabetes
Solids in urine - sediment examined. Types of cells: RBCs ; WBCs
Ability of kidneys to concentrate urine Administer ADH
become more concentrated since more fluid should be retained
Urinary Tract Infections Occurs in any portion of urinary
tract 10 - 20% of all women in US have
lower UTI at some time Limited occurrence
Effects of urea (kill bacteria) Acidic pH of urine Washing out of bacteria during
voiding Minimize urine reflux
Cystitis
Bladder inflammation
Increased urination
frequency & urgency
Pain
Cloudy urine
Blood in urine
Treatment: ABx thpy
Kidney Infection Bacterial or viral Urinary obstruction
causes backflow of urine from bladder to kidneys From blood infection Most cases in women Symptoms
Pain / Fever Increased urinary frequency
Treatment Longer use of ABx thpy
Urolithiasis Presence of stones in the
urinary tract Calculi formed by:
Calcium oxalate Calcium phosphate Uric acid
Calculi can pass through the urinary tract and/or cause an obstruction
Urolithiasis Assessment:
Acute, sharp, intermittent pain (ureteral colic)
Dull, tender ache in the flank (renal colic)
N&V, Fever & chills Hematuria / Pyuria Abd. Distention
Diagnostic Findings: KUB: visible calculi IVP: size & loc of stones Renal sonogram &
Spiral CT scan Stone Analysis –
detection of type of stone
Non-Surgical Procedures:
Extracorporeal Shock Wave
Lithotripsy
Stone dissolution
Laser impulse technology
Surgical Procedures:
Cystoscopy
Ureterolithotomy;
Pyelolithotomy; Nephrolithotomy
Polycystic Kidney Disease Genetic disorder - 500,000 cases in US Large cysts form in the kidneys Kidney hypertrophy Over time, decreasing kidney function as nephrons units
are replaced by cysts Dialysis or transplant
50% with PKD progress to kidney failure (end stage renal disease)
4th leading cause of kidney failure No cure except kidney transplant
Polycystic Kidney Disease
Acquired Cystic Kidney Disease
From long-term kidney dialysis and end-stage renal
disease
90% of people on dialysis for 5 yrs develop ACKD
Cysts may bleed
Increased risk of kidney cancer (very rare)
2 times as likely with ACKD
Diabetic Nephropathy Diabetes - Abnormally high blood glucose
Causes major problems with blood chemistry including osmotic balance
Kidneys can remove all extra glucose from bloodKidneys must work extra hard to do this
Larger urine volume as kidneys must excrete excess glucose
Diabetic Nephropathy (con’t) Prolonged high blood glucose causes nephropathy
Damage to the glomerulus and the filtering system
Proteins and blood cells that would normally not be
filtered appear in the urine
Kidney function is compromised
Diabetic nephropathy is leading cause of kidney failure
in United States
Diuretics Chemicals that enhance the urinary output include:
Any substance not reabsorbed
Substances that exceed the ability of the renal tubules
to reabsorb it
At transport max
Substances that inhibit Na+ reabsorption
Na+ drives the reabsorption of fluid
Osmotic diuretics include:
High glucose levels
H2O carried out w/ glucose
Alcohol
inhibits release of ADH
Caffeine and most diuretic drugs
inhibit Na+ reabsorption
Lasix
inhibit Na+ associated transporters
Diuretics to Treat Urinary System Dx Diuretics: increase urine volume
Aldosterone antagonists: block sodium retaining effect of aldosteroneMore sodium remains in renal tubule
More sodium excreted Where sodium goes, water goes (increased fluid
elimination Sodium and chloride reabsorption inhibitors
(thiazides)block reabsorption of sodium, potassium and
chloride Increased salt and water elimination
Treatment of Renal Failure Will develop after both kidneys are damaged
Restrict water, salt and protein intakeMinimizes volume of urine producedPrevent production of large amount of nitrogenous
waste Hemodialysis
Uses artificial membrane (replaces glomerular filtration) to filter blood.Diffusion of small ionsMinimal loss of blood protein
Dialysis fluidK+, phosphate ions, sulfate ions, urea, creatinine,
uric acid go into dialysis fluid
Treatment of Renal Failure Dialysis
15 hrs per week
Dialysis centers
Transplantation
15,000 transplants in 2003
1 yr success rate is 85-95%
Immunosupressive drugs to reduce transplant
rejection
Urinary Incontinence – Multiple Etiologies Normal effect of aging or pathology Stretching of pelvic floor during childbirth
Incontinence during sneezing and coughing (stress incontinence)
Prostate removal Neurogenic bladder dysfunction Treatment
Kegel exercises: tightening pelvic muscles as if trying to stop urination
Did you know? Infants have small bladders and the kidneys cannot
concentrate urine, resulting in frequent micturition Control of the voluntary urethral sphincter develops
with the N System about age 1 E. coli bacteria account for 80% of all urinary tract
infections Sexually transmitted diseases can also inflame the
urinary tract and result in urinary tract infections Kidney function declines with age, with many elderly
becoming incontinent