What are “spastic” and “flaccid” bladder?

Authors: SCIRE Community Team | Reviewer: Bonnie Nybo | Published: 18 January 2018 | Updated: 16 October 2024

Spastic bladder (also called “reflex bladder” or “overactive bladder”) happens when the spinal cord is injured above T12. Spastic bladder happens because the brain can no longer control reflexes in the bladder muscles. This leads to tension in the bladder wall muscle when it is supposed to be relaxed and spasms of the bladder muscles which cause emptying.

Usually, the bladder sphincter muscles are also overactive and cannot coordinate very well with the bladder wall muscle. This is called detrusor dyssynergia or detrusor sphincter dyssynergia (DSD). When this happens, the bladder sphincter muscle tightens while the bladder wall muscle contracts, like squeezing a balloon that is tied off. This can cause high pressures within the bladder that can damage the bladder and kidneys.

Symptoms of spastic bladder:

• Loss of control of bladder emptying (incontinence), leading to random emptying (accidents), inability to empty when you want to and leaking
• Reflex emptying in response to things like touching the thigh or abdomen
• People with some bladder sensation may experience sudden strong urges or a frequent need to urinate
• Incomplete emptying of the bladder caused by poor coordination of the bladder wall muscle and bladder sphincter muscles (detrusor dyssynergia)
• Reduced or complete loss of bladder sensation

Flaccid bladder (also called “non-reflex bladder” or “underactive bladder”) happens when the spinal cord is injured below T12-L1 (i.e cauda equina injuries). Flaccid bladder happens because there is a loss of both input from the brain and reflexes from the spinal cord. This causes the bladder wall muscle to stay loose and floppy all the time. When this happens, the bladder wall muscle cannot squeeze the bladder to empty urine.

Usually, the external sphincter muscle is also overly relaxed, causing leaking during activities like transfers and coughing. However, the internal sphincter muscle is often in spasm and does not relax enough to allow urine to pass out of the body easily.

Symptoms of flaccid bladder:

• Inability to empty the bladder, including loss of reflex emptying
• Incomplete bladder emptying, leading to some urine remaining in the bladder after emptying (urinary retention)
• Damage to the walls of the bladder when they are overstretched
• Backflow of urine back to the kidneys (reflux), which can damage the kidneys
• Reduced or complete loss of bladder sensation