Normal Female Bladder Function
The adult bladder is a hollow organ with a muscular wall. Urine enters the bladder from two ureters which run from the kidney to the bladder. Urine is expelled from the bladder to the exterior via the urethra.
The detrusor muscle of the bladder wall is specifically designed to be able to store urine without increasing bladder pressure. The bladder acts as a reservoir relaxing to receive urine during the filling phase and only contracts to evacuate during the voiding phase.
The urethra acts reciprocally to contract during the filling phase to keep urine in the bladder and relaxing during voiding to allow for micturition. At rest the urethra is closed and the walls coapt against each other to form a seal that acts to keep urine in the bladder. Under situations of increased abdominal pressure (coughing, sneezing, exercising) contraction of the pelvic floor muscles and muscles around the urethra act to offer increased urethral resistance and maintain continence.
This video explains the pathophysiology of the overactive bladder. Bladder overactivity is a common problem affecting nearly 1 in 7 seven women. The aim of the video is to understand what is happening when the bladder is overactive. When you understand the cause you are more likely to be compliant with the treatments.
Bladder has two distinct roles
- Storage of urine: The storage of urine differentiates adults from infants and allows us to be social without the constant leakage of urine. Under control of the brain the bladder muscle is inhibited from contracting and the urethra is contracted to aid in storage of urine.
- Voiding phase (Micturition): As the bladder fills to capacity increasing messages are sent to the brain to void (pass urine). When comfortable to void the bladder contracts and the urethra relaxes to allow voiding. Women pass urine much faster then men, at a rate of 30-50 mls a second.
Normal Adult Female Bladder Function
- Bladder capacity of approximately 500mls
- Normal void is 350-700mls of urine
- Normally voids 4-7 times a day
- Normally wakes to void at night 0-1
- With each decade after 60 years one extra void during the day or night is normal.
- No urinary urgency, frequency (voiding more often then outlined above), infection, blood or tumours (contact your local doctor).
The overactive bladder is characterised by urinary frequency (8 or greater voids in 24 hours) and urgency (a strong desire to void) with or without urge incontinence (involuntary loss of urine with urgency). This condition affects 15% of adults with half experiencing urge incontinence. Women are affected more frequently than men and the incidence increases with advancing age.
Involuntary bladder contraction resulting in urgency or incontinence and may be related to the bladder muscle contracting too quickly. Common triggers include washing hands, putting the key in the door, anxiety
Urinary urgency and or pain or urge incontinence when the bladder does not contract. Some causes include infection, inflammation, foreign bodies or tumours.
When the unstable bladder is due to neurological disease (ie. spinal cord injuries, parkinsons, alzhiemers, multiple sclerosis).
Diagnosis is made by a combination of history, examination and investigation by your doctor. Infection is usually excluded with a urine test. Your doctor may ask you to complete a 24-hour urinary diary. This is an excellent means of confirming how many times you void, the volume voided and the amount of incontinence experienced Your fluid intake may also be recorded. To download a urinary diary click HERE. Women with a hypersensitive bladder classically pass small amounts of urine frequently. Women with an unstable bladder may have normal urinary frequency but experience significant urge incontinence. Urodynamics may be required to confirm the diagnosis.
The overactive bladder is a treatable condition that you should discuss with your doctor.
The treatment options include behavioural therapy, medical and rarely surgical options.
Medical and behavioural therapies are commonly used together. Bladder retraining is the mainstay of bladder retraining which helps you to learn to overcome the urge to urinate. Pelvic floor exercises and avoiding excessive fluid intake are other methods to help control the overactive bladder.
Bladder retraining is a diversionary technique used to aid in the management of an overactive bladder. The video demonstrates how bladder retraining can be useful in improving bladder function in women with an overactive bladder. Finally the video demonstrates how you can perform bladder retraining. I hope you find the instruction helpful.
Urge Incontinence (the loss of urine with the urge to go), urgency, frequency and nocturia (going too frequently in the night) are symptoms of an irritable or overactive bladder. The detrusor (the smooth muscle pump of the bladder) is spasming or contracting before you have made the toilet either with a full or less than full bladder. Bladder retraining is the technique used to try to increase the capacity of the bladder (normal capacity 350-500mls) and decrease the sensitivity of the bladder. By teaching your bladder how to store more urine without leaking or giving uncomfortable spasms, you will have more time between voids, less discomfort or pain and more freedom to go out without constantly seeking the nearest toilet. Points to follow:
- Always follow the good bladder habits
- When you get the first urge (only if less than 3-4 hours) defer the urge
- To help you defer use the urge control techniques
Urge control techniques
- Use perineal or clitoral pressure, (hand pressure over the crutch), sitting on the edge of a chair or table
- Sitting on a rolled up towel or the edge of the bed in the morning as the feet hit the floor
- Crossing your thighs
- Squeezing your buttocks
- Curling your toes or stretching your calves
- Doing a gentle pelvic floor contraction or low gentle tummy draw in
Once the urge has passed make a decision- is the bladder full? If not defer and when the urge is gone ‘”get on with life”. If the bladder is full, use the following techniques to get to the toilet dry.
- Stand carefully and relax your chest
- Breathe easily and walk quietly to the toilet
- Count your steps and use distraction techniques to help get you to the toilet dry
Aim to go 5 to 7 times per day and 0-1 per night. Remember it is quite often difficult in the first few days (or weeks!) so perseverance with your exercises and deferring is important. These strategies used in conjunction with the medication given by your doctor will help to relax the overactive bladder.
A WIDE VARIETY OF MEDICINES ARE AVAILABLE to treat the overactive bladder. The following are possible options available but is only a guide and you should consult your doctor before considering if any treatments are suitable.
Vaginal oestrogen therapy
(Vagifem, Ovestin) is likely to be helpful in postmenopausal women to decrease urinary frequency, urgency and the need to pass urine at night (nocturia). These are used 2-3 times at week and are inserted into the vagina at night. As shown in the image the applicator is inserted in to the mid-vagina, the pessary is released and the applicator discarded. Women with a history of breast cancer should discuss this with their oncologist prior to commencing therapy.
Oxybutynin (Ditropan) Is an anticholinergic agent that act to inhibit and quieten bladder contractions. Dose: 2.5mg 2x a day up to 5mg 3x a day Side Effect: Dry mouth, blurred vision, constipation, reflux are a few. This tablet is contraindicated in women with acute angle glaucoma. Oxybutinon is also available in a patch called Oxytrol and this reduces some of the side-effects experienced with the oral form. The patch is used 2 times a week and are usually placed on the abdomen. The patch can cause redness of the skin in a small number.
Solifenacin (Vesicare) is a class of anticholinergic therapy that is specific to the bladder. Studies in 2019 demonstrated that anti-cholinergic medications may be associated with a small increased risk of memory impairment. Pleasingly, recent statistics have shown that Vesicare does not negatively impact cognitive function.
Mirabegron (Betmiga) is a newer class of medication called a beta3 agonist and works to stop the bladder contractions in a different manner to the anti-cholinergic medications above. This is an attractive option in those who are unable to tolerate, or who wish to avoid any risk of anti-cholinergic side-effects. Women with uncontrolled high blood pressure should not take this medication. Check your blood pressure with your GP every six months.
Botox injections in the bladder
An option for women who have failed all other medications. Onabotulinum toxin A (Botox) is injected into the bladder muscle and causes partial paralysis of the detrusor muscle. Each course last approximately 6-12 months and patients typically will require multiple top-ups for the botox to be effective . This is performed under sedation in hospital as a day case and the botox takes approximately 7-10 days before working.
The botox is injected into the bladder wall as shown in the image, thru a small cystoscope that is introduced via the urethra. Approximately 5% of women will have trouble emptying there bladder following botox and use of a temporary catheter would then be required. The botox is now funded on the PBS in Australia when administered by a Urogynaecologist.
Neuromodulation: S3 SNS
Neuromodulation is considered in those who have failed to respond to medical treatments. A small electric wire lead is implanted into the spine that is a connected to a small pulse generator as seen in the image below. This is similar technology to the cardiac pacemaker and has been described as a “bladder pacemaker”. The lead stimulates the S3 nerve to reduce the spasms in the bladder muscle. Initially in the first step the lead is placed in the lower spine next to the third sacral nerve that controls bladder and bowel function. This is done in the operating room and radiology imaging helps facilitate excellent placement of the lead.
If the lead when connected to the external battery for 2 weeks is effective (50% reduction in urinary urgency, frequency, night time voids and urge incontinence) that lead is connected to a permanent small battery placed in the buttock under a quick anaesthetic.
The battery last approximately 5-7 years and is easily replaced. Infection of the prosthesis is an uncommon problem but if this occurs, the device would need to be removed.
The newest model of the ‘Sacral Nerve Stimulator’ is MRI compatible.