• 3/26 Lecture 9: Urinary Pathophysiology
Urinary Tract Infections (UTIs)
Uncomplicated = normal urinary system
Complicated = abnormal urinary system
Causes
Physical
Urethral strictures
a narrowing of the lumen
occurs when infection, injury, or surgical
manipulation produces a scar
1. Mostly occurs in men
2. Severity of obstruction is dependent on
location, urethra length and diameter
Causes
1. Prostate enlargement (prostatic
hypertrophy)
2. Pelvic organ prolapse (ex: prolapsed
uterus = uterus collapses)
the abnormal descent from organ’s
original position, or herniation of organs in the pelvic cavity
3. Bladder obstruction (stones, trauma,
abdominal cavity)
Prostate enlargement / hypertrophy : enlargement of
prostate gland
Detrusor Hyperflexia
Partial obstruction of the bladder outlet / urethra
urinary stones (Calculi plural Calculus)
masses of crystals / protein
most commonly made of calcium (calcium
stone)
located in kidneys, ureters, urinary bladder
prevalence: women = 7% / men = 10%
recurrence rate: 30 - 50% within 5 years
most renal stones are unilateral
most develop first stone > 50 years old
risk factors: age, sex, geographical location
on planet (temp, humidity, rainfall), seasonal factors,
, fluid intake, diet, occupation
—> women have shorter urethra =
increased risk
—> men secrete antimicrobial film =
decreased risk
most important formation factor: urine pH from
urinalysis (UA) and temperature
UA should be clear yellow, no protein,
WBCs
cause bleeding, micro-tears along urethra /
bladder = blood clots = blocked urethra =
incontinence
Uric acid stone
type of kidney stone
urine becomes acidic and the filtrate contains
low amounts of water, allowing uric acid to crystallize
Bacterial
capsular antigens resists phagocytosis
hemolysin damages epithelium
urease positive bacteria promote infection; Proteus and
Klebsiella
Adhesins: E. coli type 1 and P. fimbria bind to
uroepithelium
E. coli contamination from colon
Klebsiella, Proteus
G(-) bacteria produce beta-lactamases and
carbapenemases —> cause penicillin, cephalopsorin,
and carbapenem resistance
Host factors
kidney stones
occur when your urine contains more crystal-
forming substances (calcium, oxalate and uric acid) than the
fluid in your urine can dilute
most common: calcium oxalate / calcium
phosphate (70- 80%)
urine pH > 7 (alkaline)
second common: Struvite (magnesium ammonium
phosphate) (15%)
, urine pH < 5 (acidic)
Diabetes Mellitus (DM)
ureteral reflux
immunosuppression
pregnancy
neurogenic bladder: lack of bladder control due to a
brain, spinal cord or nerve problem
P blood group antigens
short urethra in women
indwelling catheters
Complications of UTI
Acute Cystitis: an inflammation of the bladder
is the most common complication of UTI
some cases may show hemorrhage / pus formation
(exudate) on epithelial surface of bladder = infection
prolonged infection may lead to sloughing of the bladder
mucosa with ulcer formation
severe infections may cause necrosis of bladder wall
infecting organisms: E. coli (most common), Staph
saprophyticus (second most common)
—> years of chronic infections can lead to cancer
Interstitial cystitis
an inflamed / irritated bladder wall, can lead to scarring of
bladder
caused by warm climates , fungus
more common in people with autoimmune diseases
Pyelonephritis: acute or chronic infection of one or both upper
urinary tracts (ureter, renal pelvis, interstitium)
can involve one or both sides
—> Chronic pyleonephritis leads to scarring of one or
both kidneys
most common risk factors: urinary tract obstruction, reflux
of urine from bladder predisposing risk factors: kidney stones,
vesicoureteral reflex pregnancy neurogenic bladder, instrumentation,
female sex trauma
most common in women
can change someones personality, microbes can affect
frontal lobe of brain
, Acute Pyelonephritis
microorganisms: E. coli, Proteus & Pseudomonas
(associated with Foley catheter / surgery)
split urea molecule into ammonia = alkaline
urine = increased risk stone formation
Chronic Pyelonephritis
persistent or recurrent kidney infection leading to
scarring
prevent elimination of bacteria = inflammation =
renal pelvis and calyces alterations = tubule destruction
= atrophy / dilation, diffuse scarring = impaired uterine ability =
chronic kidney failure
Symptoms of UTI
urinary frequency
edema in bladder all stimulates discharge of stretch
receptors = sx of bladder fullness
Antibiotic resistance in UTIs
caused by antibiotic overuse
risk for resistance highest in regions with highest rates of
prescription
pts who receive Bactrim (trimethoprim-sulfamethoxazole)
treatment within last 3 months, have diabetes mellitus, have
been recently hospitalized, have community-specific antibiotic resistance
rates of > 20%
TMP-SMX and fluoroquinolone have high rate of resistance
multi-drug resistant extended spectrum beta-lactamase (ESBL)
producing E. coli occurring with no known risk factors : under
microscope, has glowing ring around microbe
cause increased cost, hospitalization, morbidity, and mortality
Prevention
drug resistance awareness / knowledge
Antibiotics (Anti-infective) Steps
1. Check culture report (3 days); know what your pt has and
check that med if effective against microorganism (prevent
superbugs and formation of resistant organisms)
2. Check temp q 4 hours, is temp > 101 consider holding med
and ask provider of cultures should be redrawn (possible
development of drug-resistant organism)
Urinary Tract Infections (UTIs)
Uncomplicated = normal urinary system
Complicated = abnormal urinary system
Causes
Physical
Urethral strictures
a narrowing of the lumen
occurs when infection, injury, or surgical
manipulation produces a scar
1. Mostly occurs in men
2. Severity of obstruction is dependent on
location, urethra length and diameter
Causes
1. Prostate enlargement (prostatic
hypertrophy)
2. Pelvic organ prolapse (ex: prolapsed
uterus = uterus collapses)
the abnormal descent from organ’s
original position, or herniation of organs in the pelvic cavity
3. Bladder obstruction (stones, trauma,
abdominal cavity)
Prostate enlargement / hypertrophy : enlargement of
prostate gland
Detrusor Hyperflexia
Partial obstruction of the bladder outlet / urethra
urinary stones (Calculi plural Calculus)
masses of crystals / protein
most commonly made of calcium (calcium
stone)
located in kidneys, ureters, urinary bladder
prevalence: women = 7% / men = 10%
recurrence rate: 30 - 50% within 5 years
most renal stones are unilateral
most develop first stone > 50 years old
risk factors: age, sex, geographical location
on planet (temp, humidity, rainfall), seasonal factors,
, fluid intake, diet, occupation
—> women have shorter urethra =
increased risk
—> men secrete antimicrobial film =
decreased risk
most important formation factor: urine pH from
urinalysis (UA) and temperature
UA should be clear yellow, no protein,
WBCs
cause bleeding, micro-tears along urethra /
bladder = blood clots = blocked urethra =
incontinence
Uric acid stone
type of kidney stone
urine becomes acidic and the filtrate contains
low amounts of water, allowing uric acid to crystallize
Bacterial
capsular antigens resists phagocytosis
hemolysin damages epithelium
urease positive bacteria promote infection; Proteus and
Klebsiella
Adhesins: E. coli type 1 and P. fimbria bind to
uroepithelium
E. coli contamination from colon
Klebsiella, Proteus
G(-) bacteria produce beta-lactamases and
carbapenemases —> cause penicillin, cephalopsorin,
and carbapenem resistance
Host factors
kidney stones
occur when your urine contains more crystal-
forming substances (calcium, oxalate and uric acid) than the
fluid in your urine can dilute
most common: calcium oxalate / calcium
phosphate (70- 80%)
urine pH > 7 (alkaline)
second common: Struvite (magnesium ammonium
phosphate) (15%)
, urine pH < 5 (acidic)
Diabetes Mellitus (DM)
ureteral reflux
immunosuppression
pregnancy
neurogenic bladder: lack of bladder control due to a
brain, spinal cord or nerve problem
P blood group antigens
short urethra in women
indwelling catheters
Complications of UTI
Acute Cystitis: an inflammation of the bladder
is the most common complication of UTI
some cases may show hemorrhage / pus formation
(exudate) on epithelial surface of bladder = infection
prolonged infection may lead to sloughing of the bladder
mucosa with ulcer formation
severe infections may cause necrosis of bladder wall
infecting organisms: E. coli (most common), Staph
saprophyticus (second most common)
—> years of chronic infections can lead to cancer
Interstitial cystitis
an inflamed / irritated bladder wall, can lead to scarring of
bladder
caused by warm climates , fungus
more common in people with autoimmune diseases
Pyelonephritis: acute or chronic infection of one or both upper
urinary tracts (ureter, renal pelvis, interstitium)
can involve one or both sides
—> Chronic pyleonephritis leads to scarring of one or
both kidneys
most common risk factors: urinary tract obstruction, reflux
of urine from bladder predisposing risk factors: kidney stones,
vesicoureteral reflex pregnancy neurogenic bladder, instrumentation,
female sex trauma
most common in women
can change someones personality, microbes can affect
frontal lobe of brain
, Acute Pyelonephritis
microorganisms: E. coli, Proteus & Pseudomonas
(associated with Foley catheter / surgery)
split urea molecule into ammonia = alkaline
urine = increased risk stone formation
Chronic Pyelonephritis
persistent or recurrent kidney infection leading to
scarring
prevent elimination of bacteria = inflammation =
renal pelvis and calyces alterations = tubule destruction
= atrophy / dilation, diffuse scarring = impaired uterine ability =
chronic kidney failure
Symptoms of UTI
urinary frequency
edema in bladder all stimulates discharge of stretch
receptors = sx of bladder fullness
Antibiotic resistance in UTIs
caused by antibiotic overuse
risk for resistance highest in regions with highest rates of
prescription
pts who receive Bactrim (trimethoprim-sulfamethoxazole)
treatment within last 3 months, have diabetes mellitus, have
been recently hospitalized, have community-specific antibiotic resistance
rates of > 20%
TMP-SMX and fluoroquinolone have high rate of resistance
multi-drug resistant extended spectrum beta-lactamase (ESBL)
producing E. coli occurring with no known risk factors : under
microscope, has glowing ring around microbe
cause increased cost, hospitalization, morbidity, and mortality
Prevention
drug resistance awareness / knowledge
Antibiotics (Anti-infective) Steps
1. Check culture report (3 days); know what your pt has and
check that med if effective against microorganism (prevent
superbugs and formation of resistant organisms)
2. Check temp q 4 hours, is temp > 101 consider holding med
and ask provider of cultures should be redrawn (possible
development of drug-resistant organism)
