In the urinary system, after both kidneys produce urine, urine flows through the ureters to be stored in the bladder, which has a control mechanism to prevent urine from leaking out. Where the bladder and urethra connects is a set of muscles that work as sphincters, acting like valves that open and close. The functions of both the bladder and sphincters are controlled by the nervous system.
 
When the bladder begins to store urine, a control system sends signals back and forth between the bladder and the central nervous system to prevent the bladder from contracting before the appropriate time. (This depends on the bladder capacity and the situation conducive to urination, which is related to human behavior. In this case, a desirable situation is being in a closed and safe place, usually the bathroom). Once in a ready environment , the brain sends a signal to the sphincter muscles to relax, and the bladder to contract to allow urine to flow out of the body.
 
People with OAB feel a strong sudden urge to urinate. They cannot wait or hold in urine. This is because the bladder sphincters get abnormal signals to urinate sooner and more forcefully although the bladder may not be full yet. At the same time, the bladder muscles may contract before the appropriate time. While the cause of this condition is still unknown, certain diseases and behaviors can contribute to this condition including the following.
 

• Nervous system diseases such as cerebrovascular disease, multiple sclerosis
• Diabetes
• Dysfunctioning nervous system that controls bladder function due to aging
• Certain diuretic medications or excessive water intake
• Too much caffeine or alcohol consumption
• Incomplete bladder emptying causing the bladder to fill up faster than usual

 
A factor that increases the risk of developing OAB is aging4, but this does not mean that all elderly people will have this condition. Thus, OAB is not part of the natural aging process. In addition, some bladder disorders such as tumors, bladder stones, or urinary tract infections can also cause symptoms similar to OAB.

To diagnose OAB, the doctor checks for symptoms and medical history and performs a physical examination and other laboratory tests including the following:

• A urine test checks for inflammation, infection, or red blood cells in the bladder, which helps rule out other diseases or disorders with similar symptoms.
• A voiding diary - a record of such entries as the number of times, the amount of urine voided each time within 24 hours, and probably the amount of fluid intake and any leakages - helps reveal the OAB patterns and seek further for the causes.
• A post-void residual (PVR) test, an ultrasound imaging, measures the amount of urine left in your bladder after urinatation, which may affect the choice of medication for treatment.
• A urodynamic study provides additional data about the urinary system before treatment consideration.

- Uroflowmetry measures the flow of urine. It tracks how fast urine flows, how much flows out, and how long it takes. It is often performed along with the post-void residual test
- Cystometry (CMG) and pressure-flow study recreate the functioning of the urinary system in detail, from the filling phase and a pressure-flow study during the voiding phase. This is usually done when the initial treatment is not effective and more information is needed before deciding on further treatment plan.
 

Common symptoms of OAB include:

• Feeling a sudden, srtrong urge to urinate and a need to reach the restroom immediately, probably with or without urine leakage
• Little urine amount despite strong urge
• Urinating more often than usual (considerably more than 8 times a day)
• Frequent urination after falling asleep, more than once per night

The most effective treatment for OAB may involve a combination of methods, including:
Behavior modification, for example:

• Avoiding or reducing caffeinated beverages, which have diuretic properties, such as tea, coffee, and soda.
• Drink the right amount of water, not too much.
• Avoid or reduce the amount of water intake 3-4 hours before bedtime.
• Practice delayed voiding, holding in urine for a little longer to extend the time between bathroom trips and keep it in an appropriate range.
• Double voiding, urinating twice, to minimize the amount of urine left in the bladder.
• Maintaining a healthy weight. Due to the increased incidence in this group of patients
• Pelvic floor muscle exercise (Kegel exercises), contracting and then relaxing the muscles, can strengthen them and improve bladder control, keeping the sudden urge to go at bay.

 
Oral medications:
Doctors may prescribe medications to reduce bladder muscle contractions, including antimuscarinics and beta3-adrenoceptor agonists, which have proved satisfactorily effective. However, both groups of drugs have different side effects. For antimuscarinics, it's dry mouth, dry throat, constipation. They are also contraindicated in patients with angle-closure glaucoma because they increase intraocular pressure. As for beta3-adrenoceptor agonists, they should not be used in patients with poorly controlled hypertension.
 
Botulinum toxin injections or Botox injections:
Botox injections are administered directly into the bladder muscles using a thin tube called a cystoscope, which is inserted through the urethra, to weaken the bladder muscles, reducing the urgency to urinate. The effect lasts about 5-9 months. Repeat injections may be required if necessary. This approach may be considered in cases where oral medications have proved ineffective or there is a need to avoid their side effects. On the other hand,
botox injections may have a rare side effect, which is urinary retention, where the bladder cannot be emptied.
 
Neuromodulation:
This is an approach involving transcutaneous electrical nerve stimulation by way of acupuncture, patches, or surgical implants to stimulate the nerves in the bladder region to return to normal function.
 
Bladder augmentation surgery:
This is a treatment for patients with severe symptoms that cannot be treated by other methods. With the increased size, the bladder can store more urine and the pressure in the bladder is reduced. In the procedure, a small amount of tissue is typically taken from the intestine and added to the wall of the bladder to make it bigger. A side effect is that the patient may need intermittent catheterization to drain the bladder as it cannot be completely emptied on its own. This is because the contraction mechanism of the digestive tract is different from that of the bladder muscles. In addition, the patient may possibly face additional risks of urinary tract infection and bladder stones.