What is a urinary tract infection (UTI)?
The urinary tract is comprised of the kidneys, ureters, bladder, and urethra (see Figure 1). A urinary tract infection (UTI) is an infection caused by pathogenic organisms (for example, bacteria, fungi, or parasites) in any of the structures that comprise the urinary tract. However, this is the broad definition of urinary tract infections; many authors prefer to use more specific terms that localize the urinary tract infection to the major structural segment involved such as urethritis(urethral infection), cystitis(bladder infection), ureter infection, and pyelonephritis (kidney infection). Other structures that eventually connect to or share close anatomic proximity to the urinary tract (for example, prostate, epididymis, and vagina) are sometimes included in the discussion of UTIs because they may either cause or be caused by UTIs. Technically, they are not UTIs and will be only briefly mentioned in this article.
UTIs are common, more common in women than men, leading to approximately 8.3 million doctor visits per year. Although some infections go unnoticed, UTIs can cause problems that range from dysuria (pain and/or burning when urinating) to organ damage and even death. The kidneys are the active organs that, during their average production of about 1.5 quarts of urine per day, function to help keep electrolytesand fluids (for example, potassium, sodium, water) in balance, assist removal of waste products (urea), and produce a hormone that aids to form red blood cells. If kidneys are injured or destroyed by infection, these vital functions can be damaged or lost.
While some investigators state that UTIs are not transmitted from person to person, other investigators dispute this and say UTIs may be contagious and recommend that sex partners avoid relations until the UTI has cleared. There is no dispute about UTIs caused by sexually transmitted disease(STD) organisms; these infections (gonorrhea, chlamydia) are easily transmitted between sex partners and are very contagious.
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| Figure 1: Picture of the urinary tract structures |
Urinary Tract Infection Causes
The urine is normally sterile. An infection occurs when bacteria get into the urine and begin to grow. The infection usually starts at the opening of the urethra where the urine leaves the body and moves upward into the urinary tract.
- The culprit in at least 90% of uncomplicated infections is a type of bacteria called Escherichia coli, better know as E. coli. These bacteria normally live in the bowel (colon) and around theanus.
- These bacteria can move from the area around the anus to the opening of the urethra. The two most common causes of this are poor hygiene and sexual intercourse.
- Usually, the act of emptying the bladder (urinating) flushes the bacteria out of the urethra. If there are too many bacteria, urinating may not stop their spread.
- The bacteria can travel up the urethra to the bladder, where they can grow and cause an infection.
- The infection can spread further as the bacteria move up from the bladder via the ureters.
- If they reach the kidney, they can cause a kidney infection (pyelonephritis), which can become a very serious condition if not treated promptly.
The following people are at increased risk of urinary tract infection:
- People with conditions that block (obstruct) the urinary tract, such as kidney stones
- People with medical conditions that cause incomplete bladder emptying (for example, spinal cord injury or bladder decompensation after menopause)
- People with suppressed immune systems: Examples of situations in which the immune system is suppressed are AIDS and diabetes. People who takeimmunosuppressant medications such as chemotherapy for cancer also are at increased risk.
- Women who are sexually active: Sexual intercourse can introduce larger numbers of bacteria into the bladder. Infection is more likely in women who have frequent intercourse. Infection attributed to frequent intercourse is nicknamed "honeymoon cystitis." Urinating after intercourse seems to decrease the likelihood of developing a urinary tract infection.
- Women who use a diaphragm for birth control
- Men with an enlarged prostate: Prostatitis or obstruction of the urethra by an enlarged prostate can lead to incomplete bladder emptying, thus increasing the risk of infection. This is most common in older men.
- Males are also less likely to develop UTIs because their urethra (tube from the bladder) is longer. There is a drier environment where a man's urethra meets the outside world, and fluid produced in the prostate can fight bacteria.
- Breastfeeding has been found to decrease the risk for urinary tract infections.
The following special groups may be at increased risk of urinary tract infection:
- Very young infants: Bacteria gain entry to the urinary tract via the bloodstream from other sites in the body.
- Young children: Young children have trouble wiping themselves and washing their hands well after a bowel movement. Poor hygiene has been linked to an increased frequency of urinary tract infections.
- Children of all ages: Urinary tract infection in children can be (but is not always) a sign of an abnormality in the urinary tract, usually a partial blockage. An example is a condition in which urine moves backward from the bladder up the ureters (vesicoureteral reflux).
- Hospitalized patients or nursing home residents: Many of these individuals are catheterized for long periods and are thus vulnerable to infection of the urinary tract. Catheterization means that a thin tube (catheter) is placed in the urethra to drain urine from the bladder. This is done for people who have problems urinating or cannot reach a toilet to urinate on their own.
What are UTI symptoms and signs in women, men, and children?
The UTI symptoms and signs may vary according to age, sex, and location of the infection in the tract. Some individuals will have no symptoms or mild symptoms and may clear the infection in about two to five days. Many people will not spontaneously clear the infection; some of the most frequent signs and symptoms experienced by most patients is a frequent urge to urinate, accompanied by pain or burning on urination. The urine often appears cloudy and occasionally reddish if blood is present. The urine may develop an unpleasant odor. Women often have lower abdominal discomfort or feel bloated and experience sensations like their bladder is full. Women may also complain of a vaginal discharge, especially if their urethra is infected, or if they have an STD. Although men may complain of dysuria, frequency, and urgency, other symptoms may include rectal, testicular, penile, or abdominal pain. Men with a urethral infection, especially if it is caused by an STD may have a pus-like drip or discharge from their penis. Toddlers and children with UTIs often show blood in the urine, abdominal pain, fever, and vomitingalong with pain and urgency with urination.
Symptoms and signs of a UTI in the very young and the elderly are not as diagnostically helpful as they are for other patients. Newborns and infants may develop fever or hypothermia, poor feeding, jaundice, vomiting, and diarrhea. Unfortunately, the elderly often have mild symptoms or no symptoms of a UTI until they become weak, lethargic, or confused
Location of the infection in the urinary tract usually gives certain symptoms. Urethral infections usually have dysuria (pain or discomfort when urinating). STD infections may cause a pus-like fluid to drain or drip from the urethra. Cystitis (bladder infection) symptoms include suprapubic pain, usually without fever and flank pain. Ureter and kidney infections often have flank pain and fever as symptoms. These symptom and signs are not highly specific, but they do help the physician determine where the UTI may be located.
Urinary Tract Infection Diagnosis
Diagnosis of a urinary tract infection is based on information you give about your symptoms, medical and surgical history, medications, habits, and lifestyle. A physical examination and lab tests complete the evaluation.
Your doctor may simply perform a urine dipstick test in the office. Only a few minutes are needed to obtain results. Your doctor may also send your urine to the lab for testing. These results take a few days to come back. This tells your doctor the exact bacteria causing your infection and to which antibiotics these bacteria have resistance or sensitivity. The culture is usually sent for special populations, including men, because they are less likely to get UTIs. It is not necessary to send a culture for everyone because the majority of UTIs are caused by the same bacteria.
- The single most important lab test isurinalysis. A sample of your urine will be tested for signs of infection, such as the presence of white blood cells and bacteria.
- In certain circumstances, your urine also may be "cultured." This means that a small amount of the urine is brushed on a sterile nutrient substance in a plastic plate. The plate is allowed to sit for a few days and then examined to see what kind of bacteria are growing on it. These bacteria are treated with different antibiotics to see which works best against them. This helps determine the best treatment for your specific infection.
- Blood tests usually are not required unless a complicated condition, such as pyelonephritis or kidney failure, is suspected.
You may be asked to give a clean-catch, midstream urine specimen. This avoids contamination of the urine with bacteria from your skin. You should be instructed in how to do this.
- Midstream means you urinate a little into the toilet before collecting a specimen. The idea is that you don't collect the urine that comes out first, as this urine is often contaminated.
- Clean-catch refers to a midstream sample that was collected after cleaning the area of the urethral opening.
- Adult women and older girls: Cleanse the area around your urethral opening gently (but completely) using a sterile wipe or soap and water. Catch the urine midstream. For some women, catheterization (inserting a tube into the bladder) may be the only way to obtain a sterile, uncontaminated specimen.
- Men and boys: A sterile specimen can usually be obtained with a midstream catch. Uncircumcised males should retract the foreskin and cleanse the area before urinating.
- Newborns: Urine may be obtained with a procedure in which a needle is introduced through the lower abdominal wall to draw (aspirate) urine from the bladder.
- Infants and children: Either catheterization or the needle aspiration method is used.
If you cannot produce a urine specimen or are unable to follow instructions for a clean-catch specimen, your health-care provider may obtain a urine specimen by catheterizing you.
- This means placing a thin tube (catheter) in your urethra to drain urine from your bladder.
- The catheter usually is removed after the bladder is emptied.
- The catheter may remain in place if you are very ill or if it is necessary to collect all urine or measure urine output.
Depending on their symptoms, young sexually active women could require a pelvic examination because pelvic infections can have similar symptoms as a urinary tract infection.
Men will most likely require a rectal examination so that the prostate can be checked. A prostate infection (prostatitis) requires a longer course of antibiotics than a urinary tract infection.
In some cases, an imaging test may be indicated to detect any underlying problem in the urinary tract that could cause an infection. This is usually only necessary in repeat infections or special circumstances (unusual bacteria, suspected anatomic abnormalities).
- An ultrasound examination can evaluate kidney and bladder problems.
- A fluoroscopic study can show any physical problems that predisposechildren to urinary tract infections.
- Intravenous pyelogram (IVP) is a special series of X-rays that uses a contrastdye to highlight abnormalities in the urinary tract.
- Cystoscopy involves insertion of a thin, flexible tube with a tiny camera on the end through the urethra into the bladder. This allows detection of abnormalities inside the bladder that might contribute to infections.
- A CT scan gives a very detailed three-dimensional picture of the urinary tract.
Imaging tests are most often needed for the following groups:
- Children with urinary tract infections, especially boys
- Up to 50% of infants and 30% of older children with a urinary tract infection have an anatomic abnormality. The child's pediatrician should investigate this possibility.
- Adults with frequent or recurrent urinary tract infections
- People who have blood in the urine
Urinary Tract Infections Treatment
UTI Home Remedy
Because the symptoms of a urinary tract infection mimic those of other conditions, you should see your health-care provider if you think you have a urinary tract infection. A urine test is needed to confirm that you have an infection. Self-care is not recommended.
You can help reduce the discomfort by taking the following steps:
- Follow your health-care provider's treatment recommendations.
- Finish all antibiotic medication even if you are feeling better before the medication is gone.
- Take a pain-relieving medication.
- Use a hot-water bottle to ease pain.
- Drink plenty of water.
- Avoid coffee, alcohol, and spicy foods, all of which irritate the bladder.
- Quit smoking. Smoking irritates the bladder and is known to cause bladder cancer.
Medical Treatment
The usual treatment for both simple and complicated urinary tract infections is antibiotics. The type of antibiotic and duration of treatment depend on the circumstances.
Lower urinary tract infection (cystitis)
- In an otherwise healthy young female, a three-day course of antibiotics is usually enough. Some providers prefer a seven-day course of antibiotics. Occasionally, a single dose of an antibiotic is used. Your health-care provider will determine which of these options is best for you.
- Adult males with a UTI require seven to 14 days of antibiotics. If the prostate is also infected (prostatitis), four weeks or more of antibiotic treatment may be required.
- Adult females with potential for or early involvement of the kidneys, urinary tract abnormalities, or diabetes are usually given a five- to seven-day course of antibiotics.
- Children with uncomplicated cystitis are usually given a 10-day course of antibiotics.
- To alleviate burning pain during urination,phenazopyridine (Pyridium) or a similar drug, can be used in addition to antibiotics for one to two days.
Upper urinary tract infection (pyelonephritis)
- Young, otherwise healthy females with symptoms of pyelonephritis can be treated as outpatients. They may receive IV fluids and antibiotics or an injection of antibiotics in the emergency department, followed by 10-14 days of oral antibiotics. They should follow up with their health-care provider in one to two days to monitor improvement.
- If you are very ill, dehydrated, or unable to keep anything in your stomach because of vomiting, an IV will be inserted into your arm. You will be admitted to the hospital and given fluids and antibiotics through the IV until you are well enough to switch to an oral antibiotic.
- A complicated infection may require treatment for several weeks.
You may be hospitalized if you have symptoms of pyelonephritis and any of the following:
- appear very ill;
- are pregnant;
- have not gotten better with outpatient antibiotic treatment;
- have underlying diseases that compromise the immune system (diabetes is one example) or are taking immunosuppressive medication;
- are unable to keep anything in your stomach because of nausea or vomiting;
- had previous kidney disease, especially pyelonephritis within the last 30 days;
- have a device such as a urinary catheter in place; or
- have kidney stones.
Urethritis in men and women can be caused by the same bacteria as sexually transmitted diseases (STDs). Therefore, people with symptoms of STDs (vaginal or penile discharge for example) should be treated with appropriate antibiotics.
UTI Prevention
Women and girls should wipe from front to back (not back to front) after going to the bathroom. This helps prevent bacteria from the anus entering the urethra.
Empty your bladder regularly and completely, especially after sexual intercourse.
Drink plenty of fluids. Cranberry juice, especially, has been shown to help prevent urinary tract infections. There is evidence that cranberries reduce the risk of the bacteria'sadhesion to bladder cells.
