Download NUR 304 Ch 27 Disorders of Lower Urinary Tract

Chapter 27
Disorders of the Bladder
and Lower Urinary Tract
Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins
Outline
• The control of urine elimination
• Disorders of lower urinary tract structure and function
• Lower urinary tract infections
• Bladder cancer
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Bladder Anatomy
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Bladder Structure
• Composed of four layers
– Serosal (outer)
– Detrusor muscle (smooth muscle fibers)
– Submucosal layer (connective and elastic tissue)
– Urothelium (innermost layer of transitional
epithelium)
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Neural Control of the Bladder
• Bladder – low pressure storage system
• Bladder filling causes  in intravesical pressure
• High sphincter pressure prevents loss of urine
• Micturation involves both sensory and motor neurons
• Normal bladder function requires coordinated interactions
between the sensory and motor components of both the
autonomic and somatic nervous system
• Centers for reflex control are located in S1-S4 and T11L2
• Coordination of micturation reflex occurs in the pons
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Bladder and Urethra Nerves
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Stretch Receptors in the Bladder
• Bladder fills with urine  stretch receptors
 Micturition center in the pons stimulated
 Spinal reflex stimulated
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Urination
• Detrusor muscle of bladder contracts to push urine
out.
• Abdominal muscles may also be used.
• Internal sphincter relaxes.
• External sphincter relaxes.
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Question
True or false?
Abdominal muscles are used during forced urination.
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Answer
True
Rationale: Passive urination occurs when the bladder’s
detrusor muscle contracts, and both internal and external
sphincter muscles are relaxed. Abdominal muscles
contract in order to force the excretion of urine.
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Parasympathetic Nerves
• The bladder fills with urine
Stretch receptors
Spinal reflex stimulated
Parasympathetic neurons
M3 receptors
Detrusor muscle contracts.
Internal sphincter relaxes and is pulled open
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Conscious Control
• The bladder fills with urine
 Stretch receptors
 Micturition center in the pons stimulated
 Detrusor muscle contracts.
 Internal sphincter relaxes and is pulled open.
 External sphincter relaxes.
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Question
Which of the following stimulate urination?
A. Parasympathetic nervous system neurons
B. Micturition center
C. Sympathetic nervous center
D. Spinal reflex
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Question
Which of the following stimulate urination?
A. Parasympathetic nervous system neurons
B. Micturition center
C. Sympathetic nervous center
D. Spinal reflex
Rationale: The micturition center in the pons and the spinal
reflex respond to stretch receptors in the bladder to
stimulate urination. The parasympathetic nervous
system neurons are stimulated by the spinal reflex to
cause urination.
The SNS (fight-or-flight) decreases activity in both the
excretory and digestive
systems.
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Lower Urinary Tract Obstruction and
Stasis
• Urine is retained in the bladder
• Retained urine predisposes to vesicoureteral reflux (VUR)
and kidney damage
• Congenital obstruction
– Meatal stenosis, spina bifida
• Acquired obstruction
– Enlarged prostate
– Urethral strictures (STIs)
– Bladder tumors
– Cystocele and rectocele
– Severe constipation, fetal impaction
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Compensation Mechanisms
• Compensatory
– Hypertrophy of the bladder muscle with
hypersensitivity to stretch receptors bladder
spasms urgency, incontinence and urinary
frequency
– Trabeculae, cellulae and diverticula develop back
pressure on the ureters hydroureters kidney
damage and UTIs
• Decompensatory
– Residual urine UTI
– Pronounced symptoms of obstruction
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Bladder Wall Hypertrophy
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Neurogenic Bladder Disorders
• Neurogenic detrusor overactivity (spastic bladder)
– Failure to relax and store urine
– Reflex bladder spasms and a decease in bladder
volume
– Caused by neural dysfunction (bladder function
regulated by segmental reflexes without control
from higher brain centers)
– ANS and somatic neurons are affected
– Causes: spinal cord injury, MS, herniated disk,
stroke
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Neurogenic Bladder Disorders
• Areflexic bladder-failure to empty urine
– Caused by neural injury
– Atony of the detrusor muscle
– Loss of perception of bladder fullness
– Voluntary urination does not occur
 Intra-abdominal pressure or manual suprapubic
pressure
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Urinary Incontinence
• Defined as involuntary loss or leakage of urine
• Types of urinary incontinence:
– Stress incontinence (weakness or disruption of
pelvic floor muscles)
– Urge incontinence
– Mixed incontinence: stress + urge incontinence
– Overflow incontinence
– Nocturnal enuresis
– Post-micturition dribble
– Continuous urinary leakage
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Scenario
A 63-year-old woman complains of stress incontinence,
and her 60-year-old husband complains of difficulty
voiding.
Question:
• Why do people of the same age and lifestyle have
opposite problems with urination?
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Scenario
A 63-year-old woman complains of stress incontinence,
and her 60-year-old husband complains of difficulty
voiding.
Answer:
• Why do people of the same age and lifestyle have
opposite problems with urination?
• Anatomical differences
– Women: weakness of pelvic floor muscles
– Men: prostatic hypertrophy
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Scenario (cont.)
Six months later, the husband develops urgency and
incontinence.
• The doctor explains that it is due to his muscle strength.
Questions:
• Which muscles is the doctor talking about?
• How did they cause incontinence?
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Scenario (cont.)
Six months later, the husband develops urgency and
incontinence.
• The doctor explains that it is due to his muscle strength.
Questions:
• Which muscles is the doctor talking about? Detrusor
muscle
– Prolonged bladder obstruction results in destruction
of nerve endings and hyperexcitability causing
urgency and frequency
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Urinary Incontinence-Diagnosis and
Treatment
• Diagnosis
– History and physical
– Voiding record
– Full drug history
• Treatment
– Depends on type, patient’s age and co-morbid
conditions
– Behavioral
– Pharmacological
– Surgical
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Lower Urinary Tract Infections
• Usually caused by bacteria that enter through the
urethra
• Mostly caused by E. coli
• Persons at risk for UTIs:
– Urinary obstruction and reflux
– Urinary catheters
– Neurogenic disorders that prevent bladder
emptying
– Pregnant, sexually active and postmenopausal
women
– Elderly
– Men with prostate disease
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Host-Agent Interactions
• Host Defenses
– Washout phenomenon
– Protective mucin layer lining the bladder
– Local immune responses (secretory IgA)
– Phagocytic blood cells
• Pathogen Virulence
– Ability of the organism to gain access to and thrive in
an environment
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Symptoms of Lower UTI
• Urinary frequency
• Lower abdominal or back discomfort
• Dysuria (burning or pain)
• Cloudy and foul-smelling urine
• Usually resolve within 48 hours of treatment
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Lower UTI: Diagnosis and Treatment
• Diagnosis
– Based on symptoms and examination of urine
– Urinalysis (microscopic or dipstick)
– Urine for culture and sensitivity
– >100,000 CFUs bacteria/ml
• Treatment
– Based on pathogen
– Based on whether the UTI is acute, recurrent, chronic
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Treatment of Lower UTI
• Acute
– usually E. coli
– short course of antibiotics
• Recurrent
– bacterial persistence or reinfection
– Removal of infectious source (catheter, stone)
– Education regarding pathogen transmission and prevention
measures
• Chronic
– Associated with obstructive uropathy or reflux
– More difficult to treat
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Scenario
Mr. K is paraplegic.
• When in the hospital, he had a catheter.
• Now he has a high fever and complains of joint and
back pain.
• He has pyuria and reports urgency.
• BUN is 78 mg/dL; PCR is 4.7 mg/dL.
Question:
• Which complications are you most worried about?
Why?
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Interstitial Cystitis
• Chronic condition characterized by urinary frequency,
urgency and severe suprapubic pain
• Changes in permeability of the urothelium
• Mast cell activation
• Neurogenic inflammation
• No definitive diagnostic tests
• Pharmacologic treatment
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Urothelial Neoplasia
• Benign papilloma
• Low-grade papillary urothelial carcinomas
• Invasive urothelial cell carcinomas
• Malignant tumors
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Bladder Cancer
• Felt to be caused by carcinogens in the urine
• Manifested by painless hematuria
• Risk factors
– Cigarette smoking
– Arsenic in drinking water
– Industrial exposure to chemicals
– Heavy, long-term use of cyclophosphamide
– Bladder radiation
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