Juan José Premoli

Disorders of urination or as they are currently called, "symptoms of the lower urinary tract", are the fourth cause of consultation in men. They can interfere with daily activity, create unpleasant habits and situations, and ultimately can alter quality of life.

Anatomy of the lower urinary tract

The bladder is an extraperitoneal, intrapelvic organ, located behind the pubic symphysis, and which, according to the degree of distention, makes contact with the anterior abdominal wall. It is lined on its inner side by the urothelium, which is a transitional epithelium. Below this layer is the bladder muscle, called the detrusor. This muscle is made up of smooth muscle fibers that are arranged in three layers, which at the level of the bladder body are difficult to identify, since they intersect changing direction and levels forming a true mesh or network, except at the level of the bladder neck where they adopt a well defined circular shape. Part of the fibers of the middle layer are arranged in an arch at the level of the bladder neck, so that when they contract, they open it. The most internal and external fibers, when reaching the bladder neck, extend longitudinally along the urethra and when contracted during urination produce an embudization and shortening of the proximal urethra. The muscle fibers located at the level of the bladder neck and the proximal urethra make up a functional unit, the internal sphincter, of involuntary activity. The external sphincter, which is voluntary, is made up of striated muscle fibers located between the two layers of the middle perineal fascia or urogenital diaphragm. These fibers surround the membranous urethra in men in an annular form, and not so completely, the lower two thirds of the urethra in women. The female urethra is a straight, membranous muscle tube 3 to 5 cm long. The male urethra is approximately 20 to 25 cm long, and is divided into the anterior and posterior urethra. The first is formed by the penile urethra that is mobile, and the bulbar urethra that is fixed. The second is made up of the membranous urethra, approximately 2 cm long, which crosses the urogenital diaphragm at which level the external sphincter is located, and the prostatic urethra 3 to 5 cm long. The prostate gland surrounds the prostatic urethra in its entirety. It is located below the bladder, is shaped like a chestnut, its consistency is fibroelastic, and it is considered an accessory sex gland, the secretion of which is part of the semen. The second is made up of the membranous urethra, approximately 2 cm long, which crosses the urogenital diaphragm at which level the external sphincter is located, and the prostatic urethra 3 to 5 cm long. The prostate gland surrounds the prostatic urethra in its entirety. It is located below the bladder, is shaped like a chestnut, its consistency is fibroelastic, and it is considered an accessory sex gland, the secretion of which is part of the semen. The second is made up of the membranous urethra, approximately 2 cm long, which crosses the urogenital diaphragm at which level the external sphincter is located, and the prostatic urethra 3 to 5 cm long. The prostate gland surrounds the prostatic urethra in its entirety. It is located below the bladder, is shaped like a chestnut, its consistency is fibroelastic, and it is considered an accessory sex gland, the secretion of which is part of the semen.

Physiology of urination

Urination is a reflex act controlled by the will, which can initiate, facilitate or inhibit it. In order to perform normally, it requires the anatomical integrity of the lower urinary tract and the neurological integrity of the medullary centers, the connecting pathways, and the superior subcortical and cortical centers.

Many aspects of vesicourethral neurophysiology are still a matter of discussion. It is accepted that there are a series of reflex arcs that interconnect the bladder with medullary centers at the sacral and lumbar level, and with subcortical centers at the level of the bulb, the pons, the nuclei of the base, the cerebellum and the cortical centers.

Spinal centers can reflexively initiate urination but are unable to coordinate or control it and generally cannot maintain it. Urination, when under control of these centers, is frequent, interrupted and usually complete, as occurs in the paraplegic. The subcortical centers would be in charge of coordinating the voiding act and the cortical centers of keeping it under the control of the will.

There is anatomical and pharmacological evidence on the existence of a sympathetic and parasympathetic interaction in the regulation and coordination of the complex bladder filling and emptying process.

The sympathetic alpha adrenergic receptors, located at the level of the neck, the bladder floor and the proximal urethra, would be responsible for urinary continence.

Beta adrenergic receptors are found on the floor and on the bladder walls and promote relaxation of the detrusor during the bladder filling process.

The parasympathetic cholinergic receptors are located on the walls of the bladder and would be responsible for detrusor contraction during urination.

In the newborn, urination is reflex and automatic and continues to be so until approximately two years of age, the age at which recognition of bladder filling begins to appear, which precedes the ability to postpone urination. With the maturation and myelination of the connecting pathways, the superior centers of the brain acquire voluntary control of the facilitator or inhibitor type of urination.

The bladder acts as a reservoir of urine between urinations; in the adult it has a capacity of 450 to 500 ml, and the first voiding desire is experienced at 100 - 150 ml.

Due to its elasticity and to reflexes coming from higher centers that inhibit the reflex contraction of the detrusor, the bladder adjusts its capacity to the maximum limit, without the intravesical pressure increasing excessively; If voluntary urination does not take place at that time, it may happen that a) urination occurs reflexively because the urinary reflex is so intense that it cannot be voluntarily inhibited, or b) urinary retention occurs.

The normal act of urination, motivated by bladder filling or distention, is voluntary and complex. In simplified form we can say that it begins with the relaxation of the muscles of the perineum and the external urethral sphincter; Almost simultaneously, and due to the voluntary suspension of the inhibitory reflexes, the contraction of the muscle fibers of the detrusor occurs, causing an increase in intravesical pressure and the opening and embudization of the neck. The proximal urethra shortens and its diameter increases, thereby decreasing the resistance to urine passage.

Detrusor contraction is maintained until all urine has been released; at that moment the bladder muscle relaxes and the external sphincter and bladder neck close.

Urinary continence is mainly maintained by the function of the internal sphincter and reinforced by the external sphincter and the pelvic floor muscles. It is through the voluntary contraction of the external sphincter that urination can be interrupted or terminated early, before the complete evacuation of the bladder.


In front of a patient with voiding disorders, and beyond the analyzes and studies that can be requested to individualize the cause of the same, it is important to carry out a detailed questioning, first letting the patient speak so that he can tell what are the symptoms that bother him , and then ask specifically with a directed questioning about voiding disorders. This should be done, because sometimes the symptoms settle very slowly and progressively, the patient gets used to them and does not spontaneously report changes in urination habits. You should not end the interrogation without first asking about the characteristics of the urine, odor, color, and if you noticed the presence of blood, air or other foreign elements.

Symptoms related to impaired urination can be divided into obstructive or voiding, and irritative or storage . Very often, with the predominance of one of them, both types of symptoms are associated in the same patient. They are obstructive or emptying symptoms , the weak voiding stream, the delay and / or effort to initiate or throughout the voiding act, the voiding in two times and the post voiding drip. Are irritative symptoms or storage, the voiding frequency or frequency, which can be day or night, in this case is called nocturia, the urgent or urgent urination, urinary incontinence, voiding pain, (which depending on its intensity, can manifest as discomfort, burning or burning ) and bladder tenesmus, which is the voiding sensation that does not disappear with urination. The irritative symptoms are those that most frequently lead to consultation, because they interfere with daily activity and sleep, altering the quality of life. Loss of urine due to a urinary fistula should not be considered as incontinence, since it does not occur naturally, but due to an abnormal path. Urinary retention is the inability to evacuate the bladder in whole or in part. If it is partial, it is called post-voiding residual urine. Pneumaturia is the expulsion of air or gas through the urethra during urination, fecaluria when they are elements of the stool, and hematuria when there is blood in the urine, which may be initial, terminal or total, asymptomatic or symptomatic. Enuresis is involuntary and unconscious urination during sleep, and it is considered that it may not be pathological until the age of four years.


  1. If you must make any voiding effort at the beginning, during or at the end of urination.

    The voiding effort may be due to:

    Obstruction to the flow of urine . The cause can be found from the bladder neck to the urethral meatus and will vary with the age of the patient. A congenital malformation is suspected in the child, such as urethral valves, bladder neck hypertrophy, or severe urethral meatus stenosis.

    In adults, the most frequent cause is related to pathologies of the prostate gland, where the effort is generally initial, unlike when there is a urethral narrowing that occurs during the entire voiding act.

    Impaired bladder muscle contractile function . The origin can be:
    • Neurological : due to injury to the bladder innervation, as in myelomeningocele, herniated disc, trauma or tumors at the level of the spinal cord
    • Myogenic : as a consequence of the chronic stretching of the detrusor that gives rise to muscle injury and denervation, producing contractile dysfunction.
    • Drug : by drugs with mainly anticholinergic action, decreasing the contractile strength of the detrusor, or alpha adrenergics increasing the muscle tone of the sphincters.
  1. If you must wait to urinate

    The delay in the initiation of urination is due to the time it takes for the bladder muscle to generate an increase in the pressure necessary to overcome the obstruction.
  1. How is the voiding stream.

    You should ask yourself about its caliber, strength and projection. The post-voiding drip in men is due to the fact that once urination is finished, a small amount of urine remains in the proximal urethra, elongated due to an enlarged prostate gland, which drains once the urination is finished.
  1. Whether urination is continuous or interrupted.

    When the obstructive process is very important, the detrusor muscle becomes fatigued, exhausts itself before the bladder empties. After a few minutes, the muscle gains strength again to expel the rest of the bladder contents. This type of urination also occurs, but without effort, when there are large bladder diverticula, or ureteral bladder reflux. The bladder urine is expelled first, and then, in a second urination, the urine from the diverticulum or the urine that has flowed back into the ureters.
  1. If urination stops abruptly.

    This is pathognomonic for bladder stones, and occurs when they lodge in the bladder neck during urination. The patient learns that by changing his position, he can mobilize the calculation of his obstructive position and restart urination.
  1. How often do you urinate during the day or if you get up to urinate during your sleeping hours.

    Normally you urinate five to eight times during the day, and once or not at all during the hours you sleep. Increased nighttime urinary frequency is called nocturia. The increase in voiding frequency may be due to:
    1. Processes that irritate the detrusor muscle. It can be due to tumors, infections, bladder stones, and inflammatory processes of the bladder (insterticial cystitis) or neighboring organs (appendicitis-diverticulitis etc,). In some cases, due to obstruction of the urinary flow produced by an enlarged prostate gland or hypertrophy of the bladder neck, the voiding frequency is due to irritability of the detrusor, secondary to its hypertrophy caused by the obstruction.

      Sometimes the origin of bladder muscle irritability may be due to a neurological disorder, such as an alteration of the higher neurological centers responsible for the inhibition of voiding reflexes, which occur during bladder filling (cerebral arteriosclerosis, cerebrovascular accident, etc. .), or from the spinal centers (herniated disc, plaque sclerosis, trauma, etc.).

      Sometimes, the pathology causing this symptom cannot be found, being a problem of the bladder, it is the bladder called non-inhibited, hyperactive or hyperreflexic primary.

    2. To residual urine. When for some reason the bladder loses its ability to evacuate completely. This incomplete emptying between urinations, which may increase over time, is the cause of voiding frequency, due to a decrease in the functional capacity of the bladder.

    3. Due to increased urine output. Taking diuretics or excessive fluid intake may increase the frequency of urination.
  1. If when voiding desire occurs you can postpone it.

    The same processes that lead to an increase in the voiding frequency, when they are more intense, give rise to this imperious urination. Sometimes when the urinary desire is so intense that it cannot be postponed or controlled, a loss of urine occurs. Urinary incontinence due to urination
  1. If you have discomfort, burning or pain when urinating.

    The presence of an inflammatory process in the bladder wall, of infectious origin, tumor or a foreign body, produces edema, loss of elasticity and increased sensitivity of the bladder muscle, making its distension and contraction painful. Inflammatory processes of the female urethra, and of the male urethra and prostate, can cause burning or voiding discomfort.
  1. If the urinary desire persists after urinating.

    It is an almost permanent urge to urinate, and usually small amounts of urine are passed with each urination. Women compare it to the pushing of labor. It occurs when there is a very intense inflammatory or irritative process of the bladder wall, or when, due to an obstructive process, the patient does not completely evacuate his bladder and after urination, the desire to urinate persists.
  1. Whether or not you feel voiding desire.

    Loss of bladder sensitivity may be due to a disorder of the bladder innervation, as in diabetic polyneuropathy, or to injury to the bladder muscle, which occurs in the case of chronic retention of urine, by prolonged stretching and subsequent injury of muscle fibers. Patients have no voiding desire or a feeling of full bladder. Patients with neurological injuries such as quadriplegics or paraplegics, do not have bladder sensitivity, they have a neurogenic bladder.
  1. If you must perform any maneuver or adopt any special position to start or maintain urination. This is a symptom that the patient frequently refers to spontaneously. It occurs when there is a detrusor contractility disorder, or a significant obstruction of urinary flow.

    The paraplegic patient is an example of the first case. His urination is reflex, but through certain stimuli, such as pubic hair traction, or blows in the suprapubic region, it can initiate it. In cases of bladder hypotonia or atony, as in myelomeningocele, when accompanied by a decrease in urethral resistance, they can, through compression of the lower abdomen, expel urine.

    In cases of significant urinary obstruction, the patient may adopt certain positions, such as sitting or squatting, to try to make better use of the abdominal press.

    It has already been mentioned, the changes in position that some patients with bladder lithiasis must make, in order to restart urination after abruptly interrupting it, by locking the stone in the bladder neck.
  1. If you have involuntary loss of urine; if it is related to the efforts or changes in position, if you have urination despite the loss of urine and if it is continuous or episodic.

    • Incontinence that only manifests itself with exertion is almost exclusive to women, especially if it is multiparous, due to a weakness of the muscles and fasciae of the pelvic floor.
    • Incontinence due to injury to the urethral vesical sphincter mechanism, are generally total, the patient has no urination, because the loss is complete. They can be due to congenital malformations as in the epispadia, or secondary to surgeries where the sphincter mechanism is injured.
    • Incontinence due to neurological or psychic injuries or diseases, occurs because the voluntary control of urination is lost.
    • Incontinence secondary to urgent urination is due to the fact that the patient cannot postpone urination and the urine escapes.
    • Incontinence due to chronic urinary retention, is known as paradox or overflow incontinence, and is characterized by continuous loss of urine, due to a decompensated, chronically distended bladder, where urine drains without force, overcoming resistance. urethral.

  2. If you urinate involuntarily when you sleep.

    Involuntary urination during sleep, or enuresis, can sometimes be accompanied by increased daytime urinary frequency and imperative urination. It is accepted that it is gradually corrected with the neurological maturation of the superior pathways and centers. Thus, at 5 years there are approximately 15% of children with nocturnal enuresis, a proportion that reduces to 1-2% at 15 years of age. In some cases an emotional triggering factor can be identified, while in others there is a clear family history. In a variable percentage (from 2 to 10%) it can be secondary to an organic lesion of the urinary tract, and in these cases it is generally accompanied by other voiding disorders.
  1. If the patient reports that he cannot urinate.

    The inability to voluntarily evacuate the urine accumulated in the bladder can occur in the following ways: a) acute, and in this case it is accompanied by a dramatic symptomatology, such as intense suprapubic pain and voiding sensation and restlessness, being able to verify in the examination a distended bladder, called a bladder balloon, which facilitates diagnosis. The cause may lie in inflammatory, obstructive, or irritative processes, or may be due to medications that increase the tone of the vesicourethral sphincter, such as alpha adrenergic drugs, or that decrease the contractile strength of the detrusor, such as anticholinergic and other drugs; or b) chronic: in this case the patient urinates due to overflow and in general the condition has been preceded by incomplete urination, with progressive accumulation of residual urine.
  1. If you have noticed changes in the color, smell, or characteristics of the urine.

    Along with changes in voiding habits, patients often spontaneously report changes in the characteristics of urine, such as a different odor or the appearance of blood, air, gas and / or fecal matter.

Physical exam

A thorough examination of the abdomen should be performed to detect or rule out abdominal tumors or a bladder balloon, and of the external genitalia to detect or rule out phimosis, urethral meatus stenosis, inflammatory processes, fistulas or prolapses in women, and malformations. congenital. If the patient reports urinary incontinence, it will be observed if it occurs spontaneously or with effort. In men, the examination will not be complete without rectal examination to record the size, sensitivity, consistency, and regularity of the prostate gland.

Diagnosis: Study methodology

Once the interrogation and physical examination have been completed, and in order to make a correct diagnosis, laboratory analysis and imaging studies are requested, leaving the most specific studies to the specialist. A useful procedure to evaluate the symptoms is the realization by the patient of a voiding diary , recording in a period of 24 hours. hour by hour, the number of urinations, the amount of urine passed in each urination, whether you had incontinence episodes, and if possible, the amount of fluid ingested.


The simple analysis of urine, correctly collected, ruling out the first voiding stream, can guide the diagnosis. If there is any doubt about the possibility of an infection, a urine culture should be done, the only way to confirm or rule out a urinary infection. With blood tests it is possible to evaluate other parameters such as blood count, blood glucose, urea, creatinine, etc. to help make the diagnosis of the pathology causing the voiding disorder. A urinary cytology will be requested, a study carried out by the anatomopathologist, when the existence of a neoplasm of the urothelium is suspected.

Imaging study

Before a urination disorder and in order to evaluate the lower urinary tract, various imaging studies can be requested. Generally, the first thing we request is a renal and bladder ultrasound in women, and a prostatic vesic in men, with post-voiding control, to evaluate residual urine. This easy, non-invasive study will be able to report on the existence of stones, tumors, the size of the prostate gland, and the existence of post-voiding residual urine. If doubts persist after this examination, the patient is not allergic to iodine and does not have renal failure, an excretory urogram may be requested, which will allow the urinary tract to be evaluated in its entirety. A computed tomography scan can also be ordered, which allows better visualization of the renal parenchyma, and if there are tumors, it will give more information on their size and extension, also allowing other pathologies not related to the urinary tract to be ruled out. If the patient is allergic to iodine, a uro-resonance may be requested, which does not use iodized substances to perform it. If a urethral stricture is suspected, a retrograde urethrogram, which evaluates the anterior urethra, or a voiding urethrogram, which evaluates the entire urethra, may be required.

Urodynamic studies

They allow a functional evaluation of the lower urinary tract and the voiding act. They are used to rule out or confirm the existence of an obstructive process, or a myogenic or neurogenic alteration of the bladder muscle. Includes the realization in isolation or simultaneously of:

Flowmeter: studies the volume of urine expelled by the urethra in the unit of time, and expressed in ml / sec. A volume of 15ml / sec rules out an obstruction. For this study to have value, you must urinate at least 150 cc.

Complete Urodynamic Study: consists of the simultaneous measurement and graphic recording of intra-abdominal pressure, intravesical pressure, and urethral flow. Evaluates the function of the bladder muscle through the pressure / volume ratio during bladder filling, and the flow and voiding volume. It is performed through continuous infusion of liquid and allows us to study if the detrusor contraction is well maintained, if its values ​​do not exceed the normal ones, if there is irritability or muscular instability and the sensitivity or pain when filling.

Special studies

Among the studies carried out by the specialist to evaluate the urinary tract, there is cystoscopy, which is the endoscopic study of the bladder, and ureter renoscopy , which is the endoscopic study of the ureter, pelvis, and renal calyces.

Differential Diagnosis

If the patient is a male adult, and reports mainly obstructive symptoms, the most frequent cause, which is the benign enlargement of the prostate gland, will be considered. Sometimes these symptoms are very slow to install, this makes the patient adapt to them, and on spontaneous questioning, do not show any voiding abnormalities. Prostate cancer does not produce symptoms in its initial state. In advanced stages these may be more rapid in evolution than in the adenoma, and may be accompanied by bone or sciatic pain, due to bone metastases. Rectal examination, laboratory, and imaging studies will help to make the differential diagnosis between these two pathologies. Narrowing of the bladder neck can also give these symptoms, generally seen in adolescents or young adults, with a history of very long-standing voiding disorders. Urethral narrowing manifests with these symptoms, and in these cases there may be a history of urethral instrumentation. To confirm the diagnosis, a urethrography should be done. It is important to ask about taking medications, especially in polymedicated elderly, since there are many drugs with anticholinergic action, which decrease the detrusor contractile force and interfere with urination. Obstructive symptoms are much less frequent in the female sex. They decrease the detrusor's contractile force and interfere with urination. Obstructive symptoms are much less frequent in the female sex. They decrease the detrusor's contractile force and interfere with urination. Obstructive symptoms are much less frequent in the female sex.irritative symptomsThey may be secondary to obstruction, but are generally due to problems related to irritation of the bladder wall and / or urethra. UTIs can appear at any age, but they are more frequent in women. They generally have an acute onset and may be accompanied by hematuria. When they compromise the upper urinary tract, they are accompanied by changes in the general condition and fever. Bladder malignancies are more common after age 50 and begin with symptoms more insidiously and progressively. Its existence is suspected due to macroscopic hematuria with negative urine culture. When there is a history of urinary lithiasis, its presence in the bladder or distal ureter should be ruled out or confirmed with ultrasound. If its existence is confirmed, a direct x-ray of the abdomen and pelvis should be done,

It should not be forgotten that inflammation of neighboring organs such as appendicitis, diverticulitis, prostatitis, and female genitalia can, by neighborhood, manifest with irritative urinary symptoms. When elimination with air, gas and / or fecal matter is added to these symptoms, we should consider the existence of an intestinal vesical fistula. Urinary incontinence with exertion is more frequent in multiparous women, and is due to an alteration of the muscle fibers and fasciae of the pelvic floor, which results in a decrease in urethral resistance to increases in intra-abdominal pressure. . If the loss occurs because the urinary urge is so severe, it is referred to as urge incontinence. If incontinence is permanent, it may be due to injury to the sphincter system, and there may be a surgical history or a neurological alteration. Sometimes, in cases of chronic urine retention, the patient constantly loses urine involuntarily, to which are added, very low volume episodic urination with the sensation of not emptying the bladder. It is the so-called overflow incontinence.