Campbell-Walsh Urology, 11th Edition

PART XII

Urine Transport, Storage, and Emptying

70

Pathophysiology and Classification of Lower Urinary Tract Dysfunction

Overview

Alan J. Wein

Questions

  1. Which of the following best describes normal bladder behavior during the filling-storage phase of the micturition cycle?
  2. Low compliance due to elastic properties
  3. High compliance due to elastic properties
  4. Low compliance due to elastic and viscoelastic properties
  5. High compliance due to elastic and viscoelastic properties
  6. High compliance due to a low relaxation coefficient of the lamina propria
  7. A patient who has significantly and urodynamically dangerous decreased compliance because of a replacement by collagen of other components of the stroma is generally best managed by:
  8. pharmacologic regimen.
  9. hydraulic distention.
  10. nerve section.
  11. augmentation cystoplasty.
  12. neuromodulation.
  13. The "guarding reflex" refers to the:
  14. abrupt increase in striated sphincter activity seen with a cough during normal bladder filling/storage.
  15. spinal sympathetic inhibition of parasympathetic ganglion activity.
  16. gradual increase in striated sphincter activity seen during normal bladder filling/storage.
  17. gradual inhibition of the pontine-mesencephalic micturition center by the cerebral cortex during normal bladder filling/storage.
  18. gradual inhibition of the sacral spinal cord ventral nuclei by the pontine-mesencephalic brainstem during normal bladder filling/storage.
  19. The primary effect of the spinal sympathetic reflexes that are evoked in animals during bladder filling and that facilitate bladder filling/storage is:
  20. neurally mediated stimulation of the α-adrenergic receptors in the area of the smooth sphincter.
  21. neurally mediated stimulation of the β-adrenergic receptors in the bladder body smooth musculature.
  22. direct inhibition of detrusor motor neurons in the sacral spinal cord.
  23. neurally mediated inhibition of cholinergic receptors in the area of the bladder body.
  24. neurally mediated sympathetic modulation of cholinergic ganglionic transmission.
  25. The organizational center for the micturition reflex in an intact neural axis is the:
  26. pontine mesencephalic formation in the brainstem.
  27. frontal area of the cerebral cortex.
  28. parietal area of the cerebral cortex.
  29. cerebellum.
  30. sacral spinal cord.
  31. Involuntary bladder contractions are most commonly seen in association with:
  32. sacral spinal cord neurologic disease or injury.
  33. infrasacral neurologic disease or injury.
  34. suprasacral neurologic disease or injury.
  35. peripheral nerve neurologic disease or injury.
  36. interstitial cystitis.
  37. Using the functional classification system, the usual lower urinary tract dysfunction seen after a stroke would be categorized as:
  38. failure to store because of the bladder (overactivity).
  39. combined deficit (failure to store because of the bladder, failure to empty because of striated sphincter dyssynergy).
  40. combined deficit (failure to store because of the bladder, failure to empty because of a nonrelaxing outlet).
  41. failure to store because of the bladder (hypersensitivity).
  42. failure to store because of the outlet.
  43. In the International Continence Society (ICS) classification system, the disorder described in question 7 would be characterized as:
  44. during storage, overactive neurogenic detrusor activity increased sensation, low bladder capacity, and incompetent urethral closure mechanism and during voiding, normal detrusor activity and abnormal urethral function (dysfunctional voiding).
  45. during storage, normal detrusor function, increased sensation, low bladder capacity, and normal urethral closure mechanism and during voiding, normal detrusor activity and abnormal urethral function (dysfunctional voiding).
  46. during storage, overactive neurogenic detrusor activity, normal sensation, normal bladder capacity, and incompetent urethral closure mechanism and during voiding, normal detrusor activity and normal urethral function.
  47. during storage, stable detrusor activity, reduced sensation, low bladder capacity, and normal urethral closure mechanism and during emptying, normal detrusor activity and abnormal urethral function (dysfunctional voiding).
  48. during storage, overactive neurogenic detrusor activity, normal sensation, low capacity, normal compliance, and normal urethral closure function and during emptying, normal detrusor activity and normal urethral function.
  49. In the current ICS terminology, "detrusor hyperreflexia" has been replaced by:
  50. detrusor instability.
  51. idiopathic detrusor overactivity.
  52. hyperactive bladder.
  53. neurogenic detrusor overactivity.
  54. neurogenic detrusor instability.
  55. In the Krane-Siroky urodynamic classification system, a patient with post–cerebrovascular accident voiding dysfunction characterized by urgency, frequency, and urge incontinence would most commonly be characterized as having:
  56. detrusor areflexia, striated sphincter dyssynergia, and smooth sphincter dyssynergia.
  57. detrusor hyperreflexia, striated sphincter synergia, and smooth sphincter dyssynergia.
  58. detrusor hyperreflexia, striated sphincter dyssynergia, and smooth sphincter synergia.
  59. detrusor areflexia, striated sphincter synergia, and smooth sphincter dyssynergia.
  60. detrusor hyperreflexia, striated sphincter synergia, and smooth sphincter dyssynergia.
  61. In the Lapides classification system, a patient with post–cerebrovascular accident voiding dysfunction characterized by urgency, frequency, and urge incontinence would most commonly be characterized as having:
  62. sensory neurogenic bladder.
  63. motor paralytic bladder.
  64. uninhibited neurogenic bladder.
  65. reflex neurogenic bladder.
  66. autonomous neurogenic bladder.
  67. A reflex neurogenic bladder, as described in the Lapides system classification, is characteristically seen in which of the following?
  68. Traumatic spinal cord injury between the sacral spinal cord and the brainstem
  69. Traumatic spinal cord injury between the sacral spinal cord and conus medullaris
  70. Cerebrovascular accident and insulin-dependent diabetes mellitus
  71. Non-insulin-dependent diabetes mellitus
  72. Multiple sclerosis
  73. In the Bors-Comarr system of classification, the term unbalanced, when applied to a patient with an upper motor neuron (UMN) lesion, implies:
  74. cerebellar lesion.
  75. involuntary bladder contractions during filling.
  76. areflexic bladder.
  77. decreased bladder compliance during filling.
  78. sphincter dyssynergia.
  79. In the Bors-Comarr system, a patient with post–cerebrovascular accident voiding dysfunction characterized by urgency, frequency, and urge incontinence would most commonly be characterized as having:
  80. a UMN lesion, complete, and balanced.
  81. a UMN lesion, complete, and imbalanced.
  82. a lower motor neuron (LMN) lesion, complete, and imbalanced.
  83. an LMN lesion, incomplete, and balanced.
  84. a UMN lesion/LMN lesion, complete, and balanced.
  85. Which of the following is an absolute requirement for a patient to be included in the symptom syndrome of overactive bladder?
  86. Nocturia
  87. Urinary frequency
  88. Urgency
  89. Urgency incontinence
  90. Detrusor overactivity
  91. Which of the following pathophysiologic factors is shared by men and women with urinary incontinence (failure to store) due to outlet underactivity?
  92. Bladder neck hypermobility
  93. Intrinsic sphincter dysfunction
  94. Proximal urethral hypermobility
  95. Nonrelaxing striated sphincter
  96. Bladder neck dysfunction

Answers

  1. d. High compliance due to elastic and viscoelastic properties. The normal adult bladder response to filling at a physiologic rate is an almost imperceptible change in intravesical pressure.During at least the initial stages of bladder filling, after unfolding of the bladder wall from its collapsed state, this high compliance (ΔV/ΔP) of the bladder is due primarily to its elastic and viscoelastic properties. Elasticity allows the constituents of the bladder wall to stretch to a certain degree without any increase in tension. Viscoelasticity allows stretch to induce a rise in tension followed by a decay (stress relaxation) when the filling (stretch stimulus) slows or stops.
  2. d. Augmentation cystoplasty.The viscoelastic properties of the stroma (bladder wall less smooth muscle and epithelium) and the urodynamically relaxed detrusor muscle account for the passive mechanical properties and normal bladder compliance seen during filling. The main components of stroma are collagen and elastin. When the collagen component increases, compliance decreases. This can occur with various types of injury, chronic inflammation, bladder outlet obstruction, and neurologic decentralization. Once decreased compliance occurs because of a replacement by collagen of other components of the stroma, it is generally unresponsive to pharmacologic manipulation, hydraulic distention, or nerve section. Most often, under those circumstances, augmentation cystoplasty is required to achieve satisfactory reservoir function.
  3. c. Gradual increase in striated sphincter activity seen during normal bladder filling/storage.There is a gradual increase in urethral pressure during bladder filling, contributed to by at least the striated sphincter element and perhaps by the smooth sphincteric element as well. The rise in urethral pressure seen during the filling/storage phase of micturition can be correlated with an increase in efferent pudendal nerve impulse frequency and in electromyographic activity of the periurethral striated musculature. This constitutes the efferent limb of a spinal somatic reflex, the so-called guarding reflex, which results in a gradual increase in striated sphincter activity during normal bladder filling and storage.
  4. e. Neurally mediated sympathetic modulation of cholinergic ganglionic transmission.Does the nervous system affect the normal bladder response to filling? At a certain level of bladder filling, spinal sympathetic reflexes facilitatory to bladder filling/storage are clearly evoked in animals, a concept developed over the years by deGroat and colleagues, who have also cited indirect evidence to support such a role in humans. This inhibitory effect is thought to be mediated primarily by sympathetic modulation of cholinergic ganglionic transmission. Through this reflex mechanism, two other possibilities exist for promoting filling/storage. One is neurally mediated stimulation of the predominantly α-adrenergic receptors in the area of the smooth sphincter, the net result of which would be to cause an increase in resistance in that area. The second is neurally mediated stimulation of the predominantly β-adrenergic receptors (inhibitory) in the bladder body smooth musculature, which would cause a decrease in bladder wall tension. McGuire has also cited evidence for direct inhibition of detrusor motor neurons in the sacral spinal cord during bladder filling that is due to increased afferent pudendal nerve activity generated by receptors in the striated sphincter. Good evidence also seems to exist to support a tonic inhibitory effect of other neurotransmitters on the micturition reflex at various levels of the neural axis. Bladder filling and consequent wall distention may also release autocrine-like factors that influence contractility (e.g., nitric oxide, prostaglandins, peptides).
  5. a. Pontine mesencephalic formation in the brainstem.Although the origin of the parasympathetic neural outflow to the bladder, the pelvic nerve, is in the sacral spinal cord, the actual organizational center for the micturition reflex in an intact neural axis is in the brainstem, and the complete neural circuit for normal micturition includes the ascending and descending spinal cord pathways to and from this area and the facilitatory and inhibitory influences from other parts of the brain.
  6. c. Suprasacral neurologic disease or injury. Involuntary contractions (IVCs) are most commonly seen associated with suprasacral neurologic disease or after suprasacral neurologic injury; however, they may also be associated with aging, inflammation or irritation of the bladder wall, bladder outlet obstruction, or stress urinary incontinence, or they may be idiopathic.
  7. a. Failure to store because of the bladder (overactivity).The classic symptoms of poststroke lower urinary tract dysfunction are urgency, frequency, and possible urgency incontinence. The urodynamic findings are generally detrusor overactivity during filling/storage with normal sensation and synergic sphincter activity during voluntary or involuntary emptying, unless the patient attempts to inhibit the involuntary contractions with striated sphincter contraction. This translates simply in the functional system to a failure to store because of the bladder.
  8. e. During storage, overactive neurogenic detrusor activity, normal sensation, low capacity, normal compliance, and normal urethral closure function and during emptying, normal detrusor activity and normal urethral function.The micturition dysfunction of a stroke patient with urgency incontinence would most likely be classified during storage as overactive neurogenic detrusor function, normal sensation, low capacity, normal compliance, and normal urethral closure function. During voiding, the dysfunction would be classified as normal detrusor activity and normal urethral function, assuming that no anatomic obstruction existed.
  9. d. Neurogenic detrusor overactivity.The Standardization Subcommittee of the ICS made some changes in definitions of terms (published as a committee report in 2002). One change was to eliminate the terms detrusor hyperreflexia and instability and replace them with the terms neurogenic detrusor overactivity and idiopathic detrusor over-activity (Abrams P et al, 2003).*
  10. b. Detrusor hyperreflexia, striated sphincter synergia, and smooth sphincter dyssynergia.When exact urodynamic classification is possible, this system provides a truly precise description of the voiding dysfunction that occurs. If a normal or hyperreflexic detrusor exists with coordinated smooth and striated sphincter function and without anatomic obstruction, normal bladder emptying should occur. Detrusor hyperreflexia is most commonly associated with neurologic lesions above the sacral spinal cord. Striated sphincter dyssynergia is most common after complete suprasacral spinal cord injury, following the period of spinal shock. Smooth sphincter dyssynergia is seen most classically in autonomic hyperreflexia, when it is characteristically associated with detrusor hyperreflexia and striated sphincter dyssynergia. Detrusor areflexia may be secondary to bladder muscle decompensation or to various other conditions that produce inhibition at the level of the brainstem micturition center, sacral spinal cord, bladder ganglia, or bladder smooth muscle. Patients with a voiding dysfunction secondary to detrusor areflexia generally attempt bladder emptying by abdominal straining, and their continence status and the efficiency of their emptying efforts are determined by the status of their smooth and striated sphincter mechanisms.
  11. c. Uninhibited neurogenic bladder.Lapides contributed significantly to the classification and care of the patient with neuropathic voiding dysfunction by slightly modifying and popularizing a system originally proposed by McLellan in 1939. Lapides' classification differs from that of McLellan in only one respect, and that is the division of the group "atonic neurogenic bladder" into sensory neurogenic bladder and motor neurogenic bladder. This remains one of the most familiar systems to urologists and nonurologists because it describes in recognizable shorthand the clinical and cystometric conditions of many types of neurogenic voiding dysfunction. An uninhibited neurogenic bladder was described originally as resulting from injury or disease to the "corticoregulatory tract." The sacral spinal cord was presumed to be the micturition reflex center, and this corticoregulatory tract was believed to normally exert an inhibitory influence on the sacral micturition reflex center. A destructive lesion in this tract would then result in overfacilitation of the micturition reflex. Cerebrovascular accident, brain or spinal cord tumor, Parkinson disease, and demyelinating disease were listed as the most common causes in this category. The voiding dysfunction is most often characterized symptomatically by frequency, urgency, and urge incontinence, as well as urodynamically by normal sensation with IVC at low filling volumes. Residual urine is characteristically low unless anatomic outlet obstruction or true smooth or striated sphincter dyssynergia occurs. The patient can generally initiate a bladder contraction voluntarily but is often unable to do so during cystometry because sufficient urine storage cannot occur before the IVC is stimulated.
  12. a. Traumatic spinal cord injury between the sacral spinal cord and the brainstem.Reflex neurogenic bladder describes the post-spinal shock condition that exists after complete interruption of the sensory and motor pathways between the sacral spinal cord and the brainstem. Most commonly, this occurs in traumatic spinal cord injury and transverse myelitis, but it may occur with extensive demyelinating disease or any process that produces significant spinal cord destruction as well. Typically, there is no bladder sensation and there is inability to initiate voluntary micturition. Incontinence without sensation generally results because of low-volume IVC. Striated sphincter dyssynergia is the rule. This type of lesion is essentially equivalent to a complete UMN lesion in the Bors-Comarr system.
  13. e. Sphincter dyssynergia.This system applies only to patients with neurologic dysfunction and considers three factors: (1) the anatomic localization of the lesion; (2) the neurologic completeness or incompleteness of the lesion; and (3) a designation as to whether lower urinary tract function is balanced or unbalanced. The latter terms are based solely on the percentage of residual urine relative to bladder capacity. Unbalanced signifies the presence of greater than 20% residual urine in a patient with a UMN lesion or 10% in a patient with an LMN lesion. This relative residual urine volume was ideally meant to imply coordination (synergy) or dyssynergia between the smooth and striated sphincters of the outlet and the bladder, during bladder contraction or during attempted micturition by abdominal straining or the Credé method.
  14. a. A UMN lesion, complete, and balanced.In this system, UMN bladder refers to the pattern of micturition that results from an injury to the suprasacral spinal cord after the period of spinal shock has passed, assuming that the sacral spinal cord and the sacral nerve roots are intact and that the pelvic and pudendal nerve reflexes are intact. LMN bladder refers to the pattern resulting if the sacral spinal cord or sacral roots are damaged and the reflex pattern through the autonomic and somatic nerves that emanate from these segments is absent. This system implies that if skeletal muscle spasticity exists below the level of the lesion, the lesion is above the sacral spinal cord and is by definition a UMN lesion. This type of lesion is characterized by IVCs during filling. If flaccidity of the skeletal musculature below the level of a lesion exists, an LMN lesion is assumed to exist, implying detrusor areflexia. Exceptions occur and are classified in a mixed lesion group characterized either by IVCs with a flaccid paralysis below the level of the lesion or by detrusor areflexia with spasticity or normal skeletal muscle tone neurologically below the lesion level. UMN lesion, complete, and imbalanced implies a neurologically complete lesion above the level of the sacral spinal cord that results in skeletal muscle spasticity below the level of the injury. IVC occurs during filling, but a residual urine volume of greater than 20% of the bladder capacity is left after bladder contraction, implying obstruction in the area of the bladder outlet during the involuntary detrusor contraction. This obstruction is generally due to striated sphincter dyssynergia, typically occurring in patients who are paraplegic and quadriplegic with lesions between the cervical and the sacral spinal cord. Smooth sphincter dyssynergia may be seen as well in patients with lesions above the level of T6, usually in association with autonomic hyperreflexia. LMN lesion, complete, and imbalanced implies a neurologically complete lesion at the level of the sacral spinal cord or of the sacral roots, resulting in skeletal muscle flaccidity below that level. Detrusor areflexia results, and whatever measures the patient may use to increase intravesical pressure during attempted voiding are not sufficient to decrease residual urine to less than 10% of bladder capacity.
  15. c. Urgency. Overactive bladder is defined (ICS) as urgency, with or without urinary urgency incontinence, usually with frequency and nocturia.One third of the patients have incontinence, but two thirds do not. Frequency and nocturia are usually but not always present. Detrusor overactivity (DO) is a urodynamic term indicating an involuntary bladder contraction. Urgency may or may not be associated with DO on a urodynamic study.
  16. b. Intrinsic sphincter dysfunction.Failure to store because of outlet underactivity in the female is due to a combination of a failure of support, generally accompanied by hypermobility of the bladder outlet and intrinsic sphincter dysfunction (ISD). It is impossible to have effort-related incontinence in the woman without some element of ISD. Outlet-related incontinence in the male is most commonly seen after prostatectomy, and there is no pathophysiologic factor of hypermobility involved. The condition is essentially ISD. A nonrelaxing striated sphincter would not produce urinary incontinence, nor would bladder neck dysfunction.

Chapter review

  1. The spinal sympathetic reflexes are facilatatory to bladder filling/storage.
  2. The micturition cycle is divided into two phases: (1) bladder filling/urine storage and (2) bladder empting/voiding.
  3. There are two urethral sphincters: (1) the smooth urethral sphincter is the smooth musculature of the bladder neck and proximal urethra; the smooth sphincter is not under voluntary control; and (2) the striated sphincter, which has two parts—the striated intramural sphincter, called the rhabdosphincter, and the external striated sphincter, which is part of the levator musculature. This sphincter is under voluntary control.
  4. While collagen content of the bladder wall increases, compliance decreases.
  5. There is increased afferent input when inflammation or irritation occurs, causing hypersensitivity to pain.
  6. The hammock hypothesis of continence proposes that there is a fixed dorsal portion of the urethra due to fascial attachments against which the ventral aspect of the urethra is compressed.
  7. Increases in intra-abdominal pressure are transmitted to the proximal urethra (as well as the mid-urethra in females).
  8. The bladder response to filling at a physiologic rate is an almost imperceptible change in intravesical pressure.
  9. Elasticity allows the constituents of the bladder wall to stretch to a certain degree without any increase in tension. Viscoelasticity allows stretch to induce a rise in tension followed by a decay (stress relaxation) when the filling (stretch stimulus) slows or stops.
  10. Involuntary contractions (IVCs) are most commonly seen associated with suprasacral neurologic disease or after suprasacral neurologic injury; however, they may also be associated with aging, inflammation, or irritation of the bladder wall, bladder outlet obstruction, or stress urinary incontinence, or they may be idiopathic.
  11. Overactive bladder is defined (ICS) as urgency, with or without urinary urgency incontinence, usually with frequency and nocturia.
  12. It is impossible to have effort-related incontinence in the woman without some element of ISD.

* Sources referenced can be found in Campbell-Walsh Urology, 11th Edition, on the Expert Consult website.