236 - Bladder Dysfunction

Question 1

How will a cervical or thoracic spinal cord injury affect bladder funcion?

(4 possible outcomes)

Answer 1

• Detrusor-external sphincter dyssenrgia
  
  • Loss of corrdination: detrusor contracts against a contracted or not relaxed external urethral sphincter
• Areflexia
• Detrusor overactivity
• Diminished compliance

Question 2

Which nerve modulates contraction of bladder neck smooth muscle and relaxation of the bladder detrusor?

Via which receeptors?

Answer 2

Hypogastric nerve (sympathetic) - important for storage

Preganglionics exit T10-L2

Bladder neck contraction via alpha-1 receptors

Bladder relaxation via beta-3 receptors

Question 3

Sustained bladder pressure above ____ will inhibit delivery of urine to the bladder

What is the consequene?

Answer 3

Sustained bladder pressure above 40 cm H2O will inhibit delivery of urine to the bladder

Results in hydronephrosis

(Kidneys are not muscular; cannot push pee down)

Question 4

How will a brain lesion (above the brainstem) affect bladder function?

Answer 4

Overactive bladder

• Loss of cortex inhibition on the pontine micturition center
• -> micturition reflex all the time, even when not appropriate
• Brain lesion -> overactive bladder*
• Spinal cord lesion can be variable, but may cause retention or overactivity*

Question 5

Which nerve mediates bladder contractions?

Answer 5

Pelvic nerve (parasympathetic)

Preganglionics exit spinal cord S2-S4

Question 6

Which area of the brain is responsible for micturition?

What events does it coordinate during micturition?

Answer 6

Pontine micturition center

• FIRST sends signals to relax teh external sphincter
• THEN signals for detrusor contraction
  
  • Pulls up and opens the bladder neck (aka internal sphincter), which allows for evacuation of urine

Cerebral cortex responsible for inhibiting pontine mictruition center so we don’t pee our pants during the exam or any other less than ideal situations

Question 7

Which types of receptors are found in the bladder detrusor?

Answer 7

M2, M3, Beta-3

M2, M3 involved in contraction so we can pee

Beta-3 involved in relaxation so we don’t have to pee all the time

Question 8

Define bladder compliance

Answer 8

Change in bladder volume / change in bladder pressure

Normally, compliance is high; means that pressure in the bladder does not change much as as it fills with urine

Question 9

List 3 treatments for stress urinary incontinence

Answer 9

Kegel exercises

Incontinence pessary

Surgery