Risk Factors for underactive bladder
Scientists are working diligently to understand what biological factors contribute to underactive bladder pathogenesis. The most common risk factors associated with this syndrome are:
Damage to the peripheral nerves of the bladder by congenital, inflammatory, neoplastic or traumatic lesions may cause the sensation of bladder filling to be absent or reduced, and large volumes of urine may accumulate, which causes difficulty in emptying the bladder.
High blood sugar causes damage to peripheral nerves supplying bladder wall. Normal urination relies on the synergy between bladder contractions and bladder neck opening. When this is interrupted, such as diabetic patients, the result is incomplete bladder emptying with significant residual volumes.
The bladder should contract normally following parasympathetic nerve stimulation, but this activity may be absent or reduced due to wasting of muscular tissue, leading to acute retention of urine and insidious voiding difficulty. Fibrosis, inflammation, and overdistension may be a contributing factor in bladder sarcopenia.
It is reported that 20 per cent of patients with pelvic procedures fail to resume usual voiding within six months. Injury to the bladder nerve supply results in damage to the parasympathetic nerve fibers which in turn cause decreased bladder contraction and potentially underactive bladder.
As we get older, the volume and elasticity of the urinary bladder can change in addition to the metabolic changes. The amount of muscular tissue as well as the amount of nerves per square mm of muscle decreases with age and occurs to the same extent in men and women.
Obstruction to the urinary outflow tract can result in chronic changes within the bladder wall. Prostatic enlargement is a very frequent cause of obstruction due to hyperplasia or, less frequently, prostate cancer. Severe vaginal prolapse also can lead to obstructed voiding.
Urinary tract Infections
Infections of the bladder and urethra have a potential to cause acute retention because of the reduced contractility of the detrusor muscle.
Drugs with antimuscarinic properties block the chemical transmission of acetylcholine so that the muscles relax - examples are Antidepressants, Antihistamines, Muscle relaxants etc.
Spinal cord injury
The degree of dysfunction is related to the severity and level of impairment. If the injury is above T12, the patient may have a reflex bladder action, which will require minimal intervention. The bladder still has some or all of its reflexes. Patient with injuries at L1 and below may have a flaccid bladder which does not contract. Bladder emptying may need to be assisted.