Neurogenic bladder
2016Neurogenic bladder
The urinary bladder is probably the only visceral smooth muscle that is under complete voluntary control from cerebral cortexIt has both somatic & autonomic innervationsThe functional features include:A normal capacity of 400 – 500 mlSensation of fullnessVolume change without change in intraluminal pressureInitiation & maintenance of contraction until bladder is emptyVoluntary initiation or inhibition of voidingThe sphincteric unit
In both male & females : two sphinctersInternal involuntary SM sph. at bladder neckExternal voluntary striated M. sph. from the prostate to membranous urethra in males & at mid urethra in femalesN.B. : the ureterovesical junction prevent backflow of urine from the bladder to the upper urinary tract.InnervationsParasympathetic : the anterior primary divisions S 2 – 4Sympathetic : T10 – L 2 Somatic motor innervation :S 2 – 3 though the pudendal N.The micturition reflex
Intact pathway via the spinal cord & pons required for normal micturition. The pontine center send either excitatory or inhibitory impulses to regulate the micturition reflex Disruption of pontine control as in upper spinal cord injury lead to contraction of the bladder without sphenecteric Relaxation ( detrusor-sphincter dyssynergia)Classification of neurogenic bladder
Upper motor neuron : spastic , uninhibited : injury above spinal cord micturition center Lower motor neuron: flaccid , atonic, areflexic : injury in the pelvic nerves or spinal micturition center Spinal shock N.B. Spinal shock Immediately after injury, regardless of the level, there is a stage of flaccid paralysis with numbness below the level of the injury that lead to bladder overfilling to the point of overflow incontinence & rectal impaction. It last few weaks up to 6 monthsFeature:
UMNL : reduced bladder capacity , involuntary detrusor contraction , high intravesical & detrusor pressure , spasticity of pelvic striated M. , autonomic dysreflexia in cervical cord lesions LMNL : large bladder capacity, lack of voluntary detrusor contraction, low intravesical pressure, deceased tone in external sphincter. N.B.: full neurologic exam. is required for those patients to assess the level of sensory and motor loss Investigations Urinalysis Renal function test Imaging study (U/S-IVU) Instrumental exam. Cystoscopy Urodynamic studiesUrodynamic studies Technique used to obtain graphic recording of activity in UB, urethral sphincters , & pelvic musculature