Copyright © 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 27 Disorders of the Bladder and Lower Urinary Tract Chapter 27 Disorders of the Bladder and Lower Urinary Tract

Copyright © 2015 Wolters Kluwer All Rights Reserved Outline The control of urine elimination Disorders of lower urinary tract structure and function Lower urinary tract infections Bladder cancer

Copyright © 2015 Wolters Kluwer All Rights Reserved Bladder Anatomy

Copyright © 2015 Wolters Kluwer All Rights Reserved 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)

Copyright © 2015 Wolters Kluwer All Rights Reserved 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 T11- L2 Coordination of micturation reflex occurs in the pons

Copyright © 2015 Wolters Kluwer All Rights Reserved Bladder and Urethra Nerves

Copyright © 2015 Wolters Kluwer All Rights Reserved Stretch Receptors in the Bladder Bladder fills with urine  stretch receptors  Micturition center in the pons stimulated  Spinal reflex stimulated

Copyright © 2015 Wolters Kluwer All Rights Reserved Detrusor muscle of bladder contracts to push urine out. Abdominal muscles may also be used. Internal sphincter relaxes. External sphincter relaxes. Urination

Copyright © 2015 Wolters Kluwer All Rights Reserved Question True or false? Abdominal muscles are used during forced urination.

Copyright © 2015 Wolters Kluwer All Rights Reserved 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.

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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.

Copyright © 2015 Wolters Kluwer All Rights Reserved Question Which of the following stimulate urination? A.Parasympathetic nervous system neurons B.Micturition center C.Sympathetic nervous center D.Spinal reflex

Copyright © 2015 Wolters Kluwer All Rights Reserved 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.

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved Bladder Wall Hypertrophy

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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?

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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?

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved 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?

Copyright © 2015 Wolters Kluwer All Rights Reserved 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

Copyright © 2015 Wolters Kluwer All Rights Reserved Urothelial Neoplasia Benign papilloma Low-grade papillary urothelial carcinomas Invasive urothelial cell carcinomas Malignant tumors

Copyright © 2015 Wolters Kluwer All Rights Reserved 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