Overactive bladder - Causes and pathogenesis

It has been reliably established that the causes of overactive bladder are the result of neurogenic and non-neurogenic lesions. Neurogenic disorders occur at the level of supraspinal centers of the nervous system and the spinal cord pathways, while non-neurogenic disorders are the result of age-related changes in the detrusor, IVO, and anatomical changes in the position of the urethra and bladder.

Some morphological changes of the detrusor in hyperactivity are known. Thus, in most patients with overactive bladder, a decrease in the density of cholinergic nerve fibers is detected, which have an increased sensitivity to acetylcholine. These changes are called "postsynaptic cholinergic denervation of the detrusor". In addition, using electron microscopy, it was possible to establish violations of normal intercellular connections in the detrusor of overactive bladder in the form of protrusion of intercellular connections and protrusion of the cell membrane of one myocyte into another with convergence of intercellular boundaries - "a tight connection of two parallel planes of adjacent myocytes". Based on these morphological changes characteristic of overactive bladder, Brading and Turner (1994) proposed a theory of the pathogenesis of detrusor hyperactivity, which is based on increased excitability of myocytes that are in close connection with each other at the sites of denervation.

It is believed that the cause of denervation, in addition to nervous disorders, may be detrusor hypoxia due to age-related ischemic changes or as a result of IVO. In the latter case, this is confirmed by the presence of a hyperreactive bladder in 40-60% of men with prostate adenoma. Thus, the primary cause of detrusor hyperactivity in a hyperreactive bladder is hypoxia developing in the detrusor due to age-related arteriolosclerosis or as a result of IVO, and leading to detrusor denervation (detected in detrusor biopsies for all types of detrusor hyperactivity). In response to a deficit in nervous regulation, compensatory structural changes occur in myonites in the form of the formation of close contacts between neighboring cells with increased nervous excitability and conductivity. And then any contraction of individual myocytes (spontaneous or provoked by stretching of the bladder wall during the period of urine accumulation) leads to involuntary contractions according to the principle of "chain reaction" of the entire detrusor. This theory of the development of detrusor hyperactivity in a hyperreactive bladder is currently considered the most correct.

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Epidemiology of overactive bladder

According to the International Continence Society, overactive bladder affects approximately 100,000,000 people worldwide. In the United States, overactive bladder is more common than diabetes, gastric ulcers, and duodenal ulcers, and is included in the top 10 most common diseases. There is reason to believe that symptoms of overactive bladder are present in 17% of the adult population of Europe. Urgent urination is observed in 16% of women in Ukraine.

Although overactive bladder is more often diagnosed in old age, its symptoms are also found in other age groups. The largest number of patients is noted at the age of over 40. At the same time, in men over 60 years old, there is a clear tendency towards an increase in the incidence, and in women, on the contrary. - towards a decrease. Thus, overactive bladder is a fairly common clinical syndrome, occurring in various age groups and leading to physical and social maladjustment.

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