Bladder physiology and
neurogenic bladder
1- bladder physiology
2-spinal cord injuries and effects on bladder
function ( neurogenic bladder)
Bladder physiology
• Bladder function :1- urine storage phase
2-emptying phase
- In filling phase :- increasing urine volume at
low intravesical pressure with closed
sphincters
- In voiding phase:-coordinated contraction of
bladder muscle with concomitant decrease of
resistance at level of smooth and striated
sphincters ( synergy)
• two Sphincters:1- smooth sphincter ( smooth muscle of bladder
neck and proximal urethra) , physiologic
sphincter and not under voluntary control
2-striated sphincter:-extrinsic or extramural striated sphincter bulky
skeletal muscle that surrounds urethra at level
of membranous urethra and middle segment
in female .
- classically described as external urethral
sphincter , and is under voluntary control
innervation
1- parasympathetic from S2-S4 :- supply bladder
and smooth sphincter, they excite bladder and
relax internal sphincter
2- sympathetic from T10-L2 supply smooth
muscle of bladder base , internal sphincter
and proximal urethra, they inhibit bladder and
excite internal sphincter
3- somatic innervation from S2-S3 travel to
striated sphincter via pudendal nerve
Incontinence
- definition:- inability to hold urine
- Types:1- urge incontinence:- inability to hold urine
associated or proceeded by urgency
- Can be either due to DOA or low compliance
DOA
Compiance
- Change in vol / change in pressue
2- stress incontinence:- inability to hold urine
due to increase intra-abdominal pressure
- Can be due to sphincter deficiency or pelvic
muscle weakness ( prolapse)
3- overflow incontinence:- Mainly in male with bladder outflow
obstruction
- Treatment is by relief of obstruction
4- continuous incontinence:- Leaking of urine continuously ( without
aggravating factor and all the times)
- Caused by fistula VVF ( extravesical
incontinence)
5- mixed incontinence:- More than one type in the same patient
Voiding dysfunction according to spinal
cord injury level
1- suprapontine ( injury above brain stem) :- results in bladder overactivity with
coordinated sphincter ( synergy)
- Sensation usually preserved but it may be
deficient
- So patient usually presents with urinary
incontinence
- Treatment by anticholinergic, botox injection
or surgical .
2- spinal cord injury infrapontine but above
spinal cord level T6 :- Detrusal overactivity
- Smooth and striated sphincter dyssynergy
- Autonomic hyperreflexia (dysreflexia)
- Impaired sensation
- So patient presents with incontinence or
retention
-Treatment:- to decrease outlet resistance by
using baclofen and botox injection
- Or use ISC to drain bladder regularly
Autonomic Dusreflexia
- Usually in spinal cord injury between
brainstem and spinal cord level T6, so
imbalanced reflex sympathetic discharge
- Triggered by:- pelvic autonomic afferent
activity ( as bladder or bowel distension ,
erection and ejaculation)
-Patient will develop hypertension, bradycardia
,headache , sweating and flushing above
spinal cord injury
-treatment:-It is considered a medical
emergency, If left untreated can cause
seizures, retinal hemorrhage, myocardial
infarction, cerebral hemorrhage, and,
ultimately, death
-Proper bladder and bowel care (ie, preventing
fecal impaction, bladder distention) are
mainstays in preventing episodes of
autonomic dysreflexia.
-if patient becomes hypertensive ,should place
the patient in an upright position immediately,
this takes advantage of an orthostatic
response and helps with the pooling of blood
in the lower extremities.
-most commonly used agents for hypertension
are nifedipine and nitrates
3- spinal cord injury between spinal cord level
T6 and S2 :-DOA
-smooth sphincter synergy but striated sphincter
dyssynergy
-impaired sensation
-patient presents with incontinence or
obstructive symptoms and rarely retention
4- injury below spinal cord level S2:- detrusor areflexia with open smooth sphincter
and striated sphincter retains a residual
resting sphincter tone and is not under
voluntary control.
- Patient presents with retention
• Treatment
• The primary aims and their prioritisation when
treating neuro-urological disorders are:
• 1.protection of the upper urinary tract;
• 2.improvement of urinary continence;
• 3.restoration of (parts of) the LUT function;
• 4.improvement of the patient’s QoL.
•