The urinary system consists of the kidneys, urethras, bladder, and urethra. The key elements in the system are the kidneys, a pair of purplish-brown organs located below the ribs toward the middle of the back. The kidneys remove excess liquids and wastes from the blood in the form of urine, keep a stable balance of salts and other substances in the blood, and produce a hormone that aids the formation of red blood cells. Narrow tubes called urethras carry urine from the kidneys to the bladder, a sack-like organ in the lower abdomen. Urine is stored in the bladder and emptied through the urethra.
The average adult passes about a quart and a half of urine each day. The amount of urine varies, depending on the fluids and foods a person consumes. The volume formed at night is about half that formed in the daytime.
Normally, urine is sterile. It is usually free of bacteria, viruses, and fungi but does contain fluids, salts, and waste products. An infection occurs when tiny organisms, usually bacteria from the digestive tract, cling to the opening of the urethra and begin to multiply. The urethra is the tube that carries urine from the bladder to outside the body. Most infections arise from one type of bacteria, Escherichia coli (E. coli), which normally lives in the colon. In many cases, bacteria first travel to the urethra. When bacteria multiply, an infection can occur. An infection limited to the urethra is called Urethritis. If bacteria move to the bladder and multiply, a bladder infection, called cystitis, results. If the infection is not treated promptly, bacteria may then travel further up the urethras to multiply and infect the kidneys. A kidney infection is called pyelonephritis.
Micro-organisms called Chlamydia and Mycoplasma may also cause urinary infections in both men and women, but these infections tend to remain limited to the urethra and reproductive system.
The urinary system is structured in a way that helps ward off infection. The urethras and bladder normally prevent urine from backing up toward the kidneys, and the flow of urine from the bladder helps wash bacteria out of the body. In men, the prostate gland produces secretions that slow bacterial growth. In both sexes, immune defences also prevent infection. But despite these safeguards, infections still occur.
Many women suffer from frequent urinary infections. Nearly 20 percent of women who have a urinary infection will have another and 30 percent of those will have yet another.
Urinary infections in men are often a result of an obstruction for example, a urinary stone or enlarged prostate or from a medical procedure involving a catheter. Urinary infections in older men are frequently associated with acute bacterial prostatitis, which can have serious consequences if not treated urgently.
Types of urinary infections:
We can distinguish three types of urinary infections; it depends on the place of infection.
The cystitis: Cystitis is an infection of the bladder; it causes burning sensations during urination and a frequent need to urinate. Infection from intestinal bacteria is by far the most frequent cause of cystitis, especially among women, who have a very short urethra. Between 20 to 40 per cent of women will get cystitis in their lifetime.
Interstitial cystitis (IC) is a condition that results in recurring discomfort or pain in the bladder and the surrounding pelvic region. The symptoms vary from case to case and even in the same individual. People may experience mild discomfort, pressure, tenderness, or intense pain in the bladder and pelvic area. Symptoms may include an urgent need to urinate (urgency), a frequent need to urinate (frequency), or a combination of these symptoms.Pain may change in intensity as the bladder fills with urine or as it empties.
Urethritis: Urethritis is an inflammation of the urethra that is usually caused by an infection. The urethra is the canal that moves urine from the bladder to the outside of the body. When this canal becomes infected, inflammation occurs due to the accumulation of white blood cells in the area. When this occurs, it is called Urethritis. Besides the urethra, the urinary tract consists of the bladder, urethras, and kidneys. Uncomplicated Urethritis usually results from infection by the bacteria Escherichia coli, commonly found in the bowel. Complicated Urethritis can occur when other problems exist, such as kidney stones, malformations of the urinary tract, spinal cord injury, or a compromised immune system.
Pyelonephritis: Pyelonephritis is a bacterial infection of one or both kidneys. Pyelonephritis is more common in women than in men. Escherichia coli, a type of bacteria that is normally found in the large intestine, causes about 90% of cases of Pyelonephritis among people who live in the community. Infections usually ascend from the genital area through the urethra to the bladder, up the urethras, into the kidneys. Infections can also be carried to the kidneys from another part of the body through the bloodstream. For instance, a staphylococcal skin infection can spread to the kidneys through the bloodstream. The risk of Pyelonephritis is increased in people with obstruction of the urethras, diabetes, in people with a weakened immune system (which reduces the body's ability to fight infection), and in pregnant women.
The causes of urinary infections:
Many factors lead to a urinary infection:
Diabetes: Diabetes Mellitus is a disorder in which blood levels of glucose are abnormally high due to either an absolute deficiency of insulin secretion, or as a result of reduced effectiveness of insulin, or both. When a patient is facing an Insulin deficiency, the sugar will be retained in the urine as a strange substance leading to a urinary infection.
Kidney stones: Kidney stones, also known as nephrolithiases, or urolithiases are solid accretions crystals of dissolved minerals in urine found inside the kidneys or urethras. They vary in size from as small as a grain of sand to as large as a golf ball. Kidney stones typically leave the body in the urine stream; if they grow relatively large before passing (on the order of millimetres), obstruction of a ureter and distention with urine can cause severe pain most commonly felt in the flank, lower abdomen and groin. Kidney stones are usually asymptomatic until they obstruct the flow of urine. Symptoms can include acute flank pain (renal colic), nausea and vomiting, restlessness, dull pain, hematuria, and possibly fever if infection is present.
Lack of liquids: The lack of liquids may lead to a urinary infection. It is important to drink sufficiently, so the bladder is flushed thoroughly. You have urge incontinence; you may try to limit your fluids to reduce the number of trips to the toilet. However, if you don't consume enough liquid to stay hydrated, your urine can occasionally become very concentrated.
Sexual relations: Bladder Infection is the most common cause of urinary infections and occurs most frequently in women. Bacteria have much easier access to the bladder in women. During sexual relations, women are at a much greater exposure to potential infection.
Hormonal factor: After menopause, a woman's body produces less of the hormone oestrogen. This drop in oestrogen can contribute to incontinence. In women, oestrogen helps keep the lining of the bladder and urethra healthy. With less oestrogen, these tissues lose some of their ability to close which means that your urethra can't hold back urine as easily as before. Meanwhile, aging of the bladder muscle affects both men and women, leading to a decrease in the bladder's capacity to store urine.
The symptoms of urinary infections:
Not everyone with a urinary infection has symptoms, but most people get at least some symptoms. These may include a frequent urge to urinate and a painful, burning feeling in the area of the bladder or urethra during urination. It is common for a person with a urinary infection to complain that, despite the urge to urinate; only a small amount of urine is passed. The urine itself may look milky or cloudy, even reddish if blood is present. Normally, a urinary infection does not cause fever if it is in the bladder or urethra. A fever may mean that the infection has reached the kidneys. Other symptoms of a kidney infection include pain in the back or side below the ribs, nausea, or vomiting. Symptoms differ, depending on whether the infection affects the lower (bladder and urethra) or upper (kidneys and urethras) parts of the urinary tract.
The symptoms of lower urinary tract infection are dysuria (burning on passing urine), frequency (frequent need to pass urine) and urgency (compelling need to urinate). The urine can be cloudy. In older men, generalized symptoms such as confusion and incontinence can be present. Urine infections are much commoner in the elderly, due to poor bladder emptying, an enlarged prostate, or incontinence associated with stroke or dementia.
The symptoms of upper urinary tract infection are the same as lower tract symptoms plus loin (flank) pain, fever and chills.
In children, symptoms of a urinary infection may be overlooked or attributed to another disorder. A urinary infection should be considered when a child seems irritable, is not eating normally, has an unexplained fever that does not go away.
How to avoid urinary infections:
It is important to drink sufficiently, so the bladder is flushed thoroughly. During urination the bladder should be emptied completely. It is a bad habit to sit on the toilet bent forward and reading while urinating. Warm clothes on the lower part of the body will also help prevent cystitis.
Urination immediately after sexual intercourse will flush out most bacteria from the urethra. Try to urinate at least once every three hours. Women who avoid urination for long periods suffer from more infections of the urinary system.
