neurogenic bladder

NEUROGENIC BLADDER
Definition: The bladder deficient in some aspect of its innervation that leads to an abnormal storage or emptying of urine.
Normal Functional Features of the Bladder
• ¬ capacity of 350-500 cc ¬
• a sensation of fullness
• ¬ ability to accommodate various volumes without a change in intravesical pressure
• ¬ ability to initiate and sustain a contraction until empty
• ¬ voluntary initiation or inhibition of voiding (despite involuntary nature of the organ)


Afferent and efferent pathways and central nervous system centers involved in micturition.

Innervation
? ¬ Afferent • somatic: pudendal nerve
• Visceral: sympathetic and parasympathetic fibers (sensation of fullness)
? ¬ Efferent • parasympathetic: S2-S4 ––> pelvic plexus ––> cholinergic postganglionic fibers ––> bladder + sphincter
• Sympathetic: T10-L2 ––> hypogastric/pelvic plexus ––> noradrenergic postganglionic fibers ––> smooth muscle of bladder base, internal sphincter, proximal urethra
• somatic: S2-S3 ––> pudendal nerve ––> external sphincter


Pathways and central nervous system centers involved in urine storage.



Micturition Reflex Pathways
? Sensory input from afferents ––> activation of sacral center ––> detrusor contraction, bladder neck opening; sphincter relaxation
? Pontine center – sends either excitatory or inhibitory impulse to regulate micturition
? coordinates detrusor contraction with simultaneous sphincter relaxation
? cerebral (suprapontine) control ––> voluntary control.
? cerebellum, basal ganglia, thalamus, and hypothalamus ? all have input at pontine micturition center


Classification of Neurogenic Bladder ¬
? failure to store
• bladder problem – detrusor hyperactivity, decreased compliance, detrusor hypersensitivity
• outlet problem – weak urethra
? ¬ failure to empty
• Bladder problem – neurologic, myogenic, psychogenic, idiopathic
• Outlet problem – anatomic, functional (detrusor-sphincter dyssynergia)
Hald-Bradley Neurotopographic Classification (NB: one of numerous classification systems)
? ¬ supraspinal lesion: defective inhibition of the voiding reflex ––> detrusor hyperreflexia with
preserved sensation
? ¬ suprasacral spinal lesion: deficit depends on level of lesion; typically spasticity below level of lesion.
? ¬ infrasacral lesion: usually flaccidity ¬
? peripheral autonomic neuropathy: deficient bladder sensation ––> increasing residual urine ––>
decompensation
? ¬ muscular lesion: can involve detrusor, smooth/striated sphincter
Neuro-urologic Evaluation
¬ history and physical exam (urologic and general neurologic); D.M. , M.S. , …etc
¬ urinalysis, renal profile
¬ imaging: IVP, U/S ––> rule out hydronephrosis and stones
¬ cystoscopy
¬ urodynamic studies
• measure pressures, flow rates during bladder filling and emptying
• incorporates EMG


Treatment
? ¬ Goals of treatment (in order of importance)
• Maintenance of low pressure storage and emptying system with minimum of tubes and collecting devices
• prevent renal failure
• prevent infections
• prevent urinary incontinence
? ¬ treatment options: depends on status of bladder and urethra
• Bladder hyperactivity ––> medications to relax bladder ,occasionally augmentation cysoplasty
• Flaccid bladder ––> intermittent catheterization
• surgery