Bladder Function After Injury

Bladder changes with injuries

After some injuries, the bladder will no longer work as it did before. Issues can emerge with bladder size, pressures, and bladder muscle function, which can affect the ability of the bladder to hold or store urine as well as properly release the urine.

Bladder function

The urinary system includes the kidneys, ureters, bladder, sphincter muscles, and the urethra. The purpose of the urinary system is to remove waste from the blood.

There are two kidneys, one on either side of the body. Blood flows to the kidneys and combines waste and water to make urine. A ureter connects each kidney to the bladder. It allows the urine to flow into the bladder. The bladder collects and holds the urine until it is time to urinate. It stretches when it is full and shrinks when it is empty.

The sphincters are two muscles in the bladder that close to keep urine in the bladder and open to let urine out of the bladder. The urethra is a muscular tube that leads from the bladder to the outside of the body. This is the exit point for urine to leave the body.

The bladder empties when the brain sends messages through the spinal cord that tell the bladder to contract so the sphincter muscles will open. When the sphincter opens, the bladder drains.

Process of normal urination

  1. The bladder stretches as it fills with urine.
  2. This stretching pushes on area nerves.
  3. The nerves send a message from the bladder to the spinal cord. Part of the message loops around in the cord, setting off a reflex, which causes the bladder to contract. The other part of the message goes to the brain. The urge or feeling to urinate is felt.
  4. At this point, the brain decides if it is an acceptable time to urinate. If it is a good time to urinate, the brain sends a message back down the cord to tell the sphincters to open and let the urine exit the body. If it is not a good time, the brain sends a message back down the cord to tell the sphincters to stay closed and keep the urine in the bladder.

Bladder function after brain injury

Bladder problems are common after a brain injury. Possible issues include:

  • Retention: Keeping too much urine in the bladder
  • Urgency: Feeling the need to urinate often
  • Incontinence: Having a wetting accident

Urinary retention happens when the bladder cannot release urine correctly. Bladders that are too full may be painful and cause infections. The urine will need to be emptied by a tube called a catheter. The catheter may stay in the bladder for a period of time or can be used on an intermittent basis.

Urgency and incontinence happen when the brain cannot understand the messages sent by the
bladder.

  • Sometimes the bladder may work fine, but the person does not remember what the urge to go feels like. Because the urge is not recognized, the brain cannot decide if it is an acceptable time to urinate. It may release the urine at the wrong time.
  • Sometimes people may feel the urge, but not in a timely fashion. By the time it is known, it may be too late to get to a restroom.

Challenges to consider

In addition to the problems associated with nerve pathways up and down the spinal cord after injury, how the bladder functions will depend in part on where the injury is located, above or below the spine’s T12 level.

Reflex bladder

When the bladder empties by reflex, it is called a reflex bladder. For a reflex to occur, the bladder message needs to travel within the cord at any level but does not need to travel up to the brain.

If the injury is above the T12 level, the bladder may empty by reflex. Any injury in this area may be able to have a reflex bladder.

  • The bladder fills with urine and stretches.
  • The stretching bladder pushes out onto nearby nerves.
  • The nerves send signals to the spinal cord.
  • The message loops around in the cord, below the injury, and sets off the reflex.
  • The message goes back down the cord to the bladder.
  • The bladder contracts, the sphincter muscles open and the urine is let out. It may let the urine out at an inconvenient time because the brain it not involved to determine the optimal time to urinate. Therefore, the person could have bladder accidents at inappropriate times.

Areflexic bladder

When the bladder is not able to empty by a reflex, it is called an areflexic bladder.

If the spinal cord injury is below the T12 level, the bladder will probably not be able to empty by a reflex. Because the spinal cord ends at about L2, the signals of a full bladder have no place to travel. Since the injury is below the level of the cord, the signals cannot ever reach the cord to stimulate the reflex to occur.

  • The bladder fills with urine and stretches.
  • The stretching bladder pushes out onto nearby nerves.
  • The nerves send signals to the spinal cord, but they are not able to reach the cord. The signals are there but have no place to travel.
  • Because the cord never received the signals, the bladder does not get a message to contract. The sphincters stay closed.
  • The urine does not empty by reflex, nor does the brain instruct the bladder to empty at all since the signals are not able to reach the cord or the brain.
  • The bladder becomes very full. When it becomes too full, the urine will eventually leak out from the bladder, resulting in bladder accidents.

Keeping a schedule

A urination schedule, also called a toileting program, helps retrain the bladder to regular activity over a week or two.

  • Make a schedule with two-hour intervals marked clearly. Leave room for notes beside each entry.
  • Take the person to the bathroom and have him/her sit on the toilet and urinate. Do this every two hours while the person’s awake and before bedtime. Record results on the urination schedule.
  • Increase the interval time when there are no more wetting accidents. For example, start toileting every three hours instead of every two hours. If wetting accidents happen, decrease the time to every 1.5 hours during the day and every four hours during the night.
  • If wetting accidents continue or if they suddenly recur after retraining, call the doctor. This may be a sign of other bladder problems.

Wetting accidents at night

  • Sometimes it is helpful to decrease the amount of fluids taken in the evening. For example, stop drinking fluids about three hours before going to bed.
  • Make sure the patient goes to the bathroom right before going to bed.

Increasing frequency, incomplete emptying

  • Call the doctor if this happens. It is possible that the patient has a bladder infection or other bladder problems.
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