- Causes/Risk Factors
- When to See a Doctor
What is a urinary tract infection (UTI)?
- The kidneys are a pair of small organs that lie on either side of the spine at about waist level. They have several important functions in the body, including removing waste and excess water from the blood and eliminating them as urine. These functions make them important in the regulation of blood pressure. Kidneys are also very sensitive to changes in blood sugar levels and blood pressure and electrolyte balance. Both diabetes and hypertension can cause damage to these organs.
- Two ureters, narrow tubes about 10 inches long, drain urine from each kidney into the bladder.
- The bladder is a small sac-like organ that collects and stores urine. When the urine reaches a certain level in the bladder, we experience the sensation that we have to void, then the muscle lining the bladder can be voluntarily contracted to expel the urine.
- The urethra is a small tube connecting the bladder with the outside of the body. A muscle called the urinary sphincter, located at the junction of the bladder and the urethra must relax at the same time the bladder contracts to expel urine.
Any part of this system can become infected. As a rule, the farther up in the urinary tract the infection is located, the more serious it is.
- The upper urinary tract is composed of the kidneys and ureters. Infection in the upper urinary tract generally affects the kidneys (pyelonephritis), which can cause fever, chills, nausea, vomiting, and other severe symptoms.
- The lower urinary tract consists of the bladder and the urethra. Infection in the lower urinary tract can affect the urethra (urethritis) or the bladder (cystitis).
In the United States, urinary tract infections account for more than 10 million visits to medical offices and hospitals each year.
What are causes and risk factors for a urinary tract infection?
The urine is normally sterile. An infection occurs when bacteria get into the urine and begin to grow. The bacterial 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 known as E. coli. These bacteria normally live in the bowel (colon) and around the anus.
- These bacteria can move from the area around the anus to the opening of the urethra. The two most common causes of this are improper wiping 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)
- Postmenopausal women: Decreased circulating estrogen makes the urinary tract more vulnerable to a UTI.
- People with suppressed immune systems: Examples of situations in which the immune system is suppressed are HIV/AIDS and diabetes. People who take immunosuppressant medications such as chemotherapy for cancer also are at increased risk.
- Sexually active women: Sexual intercourse can introduce larger numbers of bacteria into the bladder. 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.
- Breastfeeding has been found to decrease the risk for urinary tract infections in children.
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.
- Patients using catheters: If a patient is required to empty their bladder using a catheter, they are at increased risk for infection.
Are urinary tract infections contagious?
No. Urinary tract infections (UTIs) are not contagious.
What are urinary tract infection symptoms and signs?
Lower urinary tract infection (infections of the bladder or urethra)
- Bladder (cystitis, or bladder infection): The lining of the urethra and bladder becomes inflamed and irritated.
- Dysuria: pain or burning during urination
- Frequency: more frequent urination (or waking up at night to urinate, sometimes referred to as nocturia); often with only a small amount of urine
- Urinary urgency: the sensation of having to urinate urgently
- Cloudy, bad-smelling, or bloody urine
- Lower abdominal pain or pelvic pressure or pain
- Mild fever (less than 101 F), chills, and "just not feeling well" (malaise)
- Urethra (urethritis): Burning with urination
Upper urinary tract infection (pyelonephritis, or kidney infection)
Symptoms develop rapidly and may or may not include the symptoms of a lower urinary tract infection.
- Fairly high fever (higher than 101 F)
- Shaking chills
- Flank pain: pain in the back or side, usually on only one side at about waist level
In newborns, infants, children, and elderly people, the classic symptoms of a urinary tract infection may not be present. Other symptoms may indicate a urinary tract infection.
- Newborns: fever or hypothermia (low temperature), poor feeding, jaundice
- Infants: vomiting, diarrhea, fever, poor feeding, not thriving
- Children: irritability, eating poorly, unexplained fever that doesn't go away, loss of bowel control, loose bowels, change in urination pattern
- Elderly people: fever or hypothermia, poor appetite, lethargy, change in mental status
Pregnant women are at increased risk for a UTI. Typically, pregnant women do not have unusual or unique symptoms. If a woman is pregnant, her urine should be checked during prenatal visits because an unrecognized infection can cause pregnancy health complications.
Although most people have symptoms of a urinary tract infection, some do not.
The symptoms of urinary tract infection can resemble those of sexually transmitted diseases.
- Scans Show Brain Changes in People With Long COVID
- Got GERD? Eat This Way to Help Avoid Symptoms
- 5 Women Contracted Syphilis Affecting the Eyes From the Same Asymptomatic Man
- Long COVID Now Common in U.S. Nursing Homes
- Breathing in Coal-Based Pollution Could Be Especially Deadly: Study
- More Health News »
When should people seek medical care for a UTI?
Any adult or child who develops any of the symptoms of a urinary tract infection needs to be evaluated by a medical professional, preferably within 24 hours. Most medical offices can test urine for infection by using a quick urine "dipstick" test.
- Someone who has symptoms of a lower urinary tract infection should call a health care professional for an appointment, preferably on the same day that symptoms are recognized.
- Someone who has symptoms of an upper urinary tract infection involving the kidneys should call a health care professional immediately. Depending on the situation, he or she will recommend either a visit to the office or a hospital emergency department.
If someone has symptoms of a lower urinary tract infection and any of the following applies, he or she may be at risk for complications of the urinary tract infection.
- Vomiting and inability to keep down clear fluids or medication
- Not better after taking antibiotics for two days
- Having diabetes or another disease that affects the immune system
- Taking medication that suppresses the immune system such as cancer chemotherapy
Infants, children, and elderly people with any of the signs and symptoms of UTI should see their health care professional as soon as possible or go to an emergency department for evaluation.
- Fever, lethargy, and poor appetite may indicate a urinary tract infection in these groups, but they may also be signs of something more serious.
- Urinary tract infections have the potential to make these vulnerable people very ill when the bacteria spread into the bloodstream.
How are urinary tract infections diagnosed?
Diagnosis of a urinary tract infection is based on information someone gives about his or her symptoms, medical and surgical history, medications, habits, and lifestyle. A physical examination and lab tests complete the evaluation.
A health care professional may simply perform a urine dipstick test in the office. Only a few minutes are needed to obtain results. Your health care provider may also send a urine sample to the lab for culture testing (see below). These results take a few days to come back. This tells the doctor the exact bacteria causing the 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 is urinalysis. A urine culture will be tested for signs of infection, such as the presence of white blood cells and bacteria.
- In certain circumstances, 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 the specific infection.
- Blood tests usually are not required unless a complicated condition, such as pyelonephritis or kidney failure, is suspected.
For a culture specimen, the patient will be asked to give a clean-catch, midstream urine specimen. This avoids contamination of the urine with bacteria from the skin. Patients will be instructed on how to do this.
- Midstream means urinating a little into the toilet before collecting a specimen. The idea is to avoid collecting 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 the 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 catheter or 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 someone cannot produce a urine specimen or is unable to follow instructions for a clean-catch specimen, a health care professional may obtain a urine specimen by catheterization.
- This means placing a thin tube (catheter) in the urethra to drain urine from the bladder.
- The catheter usually is removed after the bladder is emptied.
- The catheter may remain in place if someone is very ill or if it is necessary to collect all urine or measure urine output.
Depending on their symptoms, sexually active women could require a pelvic examination because pelvic infections can have similar symptoms as a urinary tract infection. Males will require a genital examination, and depending on the symptoms, most likely a prostate examination. A prostate infection (prostatitis) requires a longer course of antibiotics than 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.
Rarely, 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 predispose children to urinary tract infections.
- Intravenous pyelogram (IVP) is a special series of X-rays that uses a contrast dye to highlight abnormalities in the urinary tract.
- Cystoscopy involves the insertion of a thin, flexible tube with a tiny camera on the end through the urethra into the bladder. This allows the 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 repeat 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
What is the treatment for a urinary tract infection?
The usual treatment for both simple and complicated urinary tract infections is antibiotics. The type of antibiotic and duration of treatment depends on the circumstances.
Examples of common antibiotics used in treatment include, but are not limited to, amoxicillin, sulfamethoxazole/trimethoprim (Bactrim), ciprofloxacin, nitrofurantoin (Macrobid), and many others. Your health care provider will choose the appropriate medication for your condition and the specific causative organisms.
Lower urinary tract infection (cystitis, or bladder infection)
- In an otherwise healthy person, 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. A health care professional will determine which of these options is best.
- In adult males, 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 patients 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 professional in one to two days to monitor improvement.
- If someone is very ill, dehydrated, or unable to keep anything in his or her stomach because of vomiting, an IV will be inserted into the arm. He or she will be admitted to the hospital and given fluids and antibiotics through the IV until he/she is well enough to switch to an oral antibiotic.
- A complicated, acute infection may require treatment for several weeks.
A person may be hospitalized if he or she has 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 the 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
- 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. Your doctor will have to evaluate you for urinalysis as well as UTIs if you experience any pain in the genital area.
Are there are home remedies for a urinary tract infection?
There are a variety of self-care measures (home remedies) and other treatments available for urinary tract infections.
- Use a hot-water bottle to ease the pain.
- Drink plenty of water.
- Avoid coffee, alcohol, and spicy foods, all of which irritate the bladder.
- There are some indications that cranberry juice can help fight a urinary tract infection.
Because the symptoms of a urinary tract infection mimic those of other conditions, someone should see a health care professional if a urinary tract infection is suspected. A urine test is needed to confirm an infection. Self-care is not recommended.
How long does a UTI last after treatment with antibiotics?
Symptoms of lower urinary tract infections usually resolve within 24 hours of starting the medication. The full amount of prescribed antibiotics should be taken even if the symptoms are fully gone.
Upper urinary tract symptoms (pyelonephritis) will usually take longer to respond to treatment. The patient will usually improve within 24 hours, but it will often take long until all symptoms resolve.
Is it possible to prevent a urinary tract infection?
- Women and girls should wipe from front to back (not back to front) after bowel movements. This helps prevent bacteria from the anus from entering the urethra.
- Empty the bladder regularly and completely, especially after sexual intercourse.
- Drink plenty of fluids, especially water.
- Cranberry juice, especially, has been shown to help prevent urinary tract infections.
- Women should empty their bladder soon after sexual intercourse.
What is the prognosis of a urinary tract infection?
- For people with uncomplicated cystitis or pyelonephritis, antibiotic treatment usually brings complete resolution of the infection.
- If not treated promptly, urinary tract infections can cause permanent scarring of the urinary tract.
- Recurrent urinary tract infections can become a problem and will require close monitoring by your health care provider.
- Pyelonephritis, if not treated promptly, can spread to the bloodstream and cause a very severe infection.
- Short-term and long-term kidney damage can be a result of pyelonephritis.
- Death from pyelonephritis is rare in otherwise healthy people.
- Factors associated with the poor outcome are old age or general debility, kidney stones, recent hospitalization, diabetes, sickle cell disease, cancer, or chronic kidney disease.
Health Solutions From Our Sponsors
Top Urinary Tract Infection Related Articles
Bacterial Infections 101Get more information on bacterial skin infections, which bacteria cause food poisoning, sexually transmitted bacteria, and more. Explore the most common bacterial infections.
Bladder PictureThe urinary bladder is a muscular sac in the pelvis, just above and behind the pubic bone. See a picture of the Bladder and learn more about the health topic.
Blood Clots (in the Leg)Blood clots can form in the heart, legs, arteries, veins, bladder, urinary tract, and uterus. Risk factors include high blood pressure and cholesterol, diabetes, smoking, and family history. Symptoms and treatment depend on the location of the clot.
Breastfeeding (and Formula Feeding)It's important to know whether you will breastfeed or bottle-feed your baby prior to delivery, as the breasts' ability to produce milk diminishes soon after childbirth without the stimulation of breastfeeding. Breast milk is easily digested by babies and contains infection-fighting antibodies and cholesterol, which promotes brain growth. Formula-fed babies actually need to eat somewhat less often since formula is less readily digested by the baby than human milk. This article explores the advantages and disadvantages of both forms of feeding.
CT Scan (Computerized Tomography)A CT scan is an X-ray procedure that combines many X-ray images with the aid of a computer to generate cross-sectional and three-dimensional images of internal organs and structures of the body. A CT scan is a low-risk procedure. Contrast material may be injected into a vein or the spinal fluid to enhance the scan.
Common Medical Abbreviations & Terms
Doctors, pharmacists, and other health-care professionals use abbreviations, acronyms, and other terminology for instructions and information in regard to a patient's health condition, prescription drugs they are to take, or medical procedures that have been ordered. There is no approved this list of common medical abbreviations, acronyms, and terminology used by doctors and other health- care professionals. You can use this list of medical abbreviations and acronyms written by our doctors the next time you can't understand what is on your prescription package, blood test results, or medical procedure orders. Examples include:
- ANED: Alive no evidence of disease. The patient arrived in the ER alive with no evidence of disease.
- ARF: Acute renal (kidney) failure
- cap: Capsule.
- CPAP: Continuous positive airway pressure. A treatment for sleep apnea.
- DJD: Degenerative joint disease. Another term for osteoarthritis.
- DM: Diabetes mellitus. Type 1 and type 2 diabetes
- HA: Headache
- IBD: Inflammatory bowel disease. A name for two disorders of the gastrointestinal (BI) tract, Crohn's disease and ulcerative colitis
- JT: Joint
- N/V: Nausea or vomiting.
- p.o.: By mouth. From the Latin terminology per os.
- q.i.d.: Four times daily. As in taking a medicine four times daily.
- RA: Rheumatoid arthritis
- SOB: Shortness of breath.
- T: Temperature. Temperature is recorded as part of the physical examination. It is one of the "vital signs."
CT Scan vs. MRI
CT scan (computerized tomography) is a procedure that uses X-rays to scan and take images of cross-sections of parts of the body. CT scan can help diagnose broken bones, tumors or lesions in areas of the body, blood clots in the brain, legs, and lung, and lung infections or diseases like pneumonia or emphysema.
MRI (magnetic resonance imaging) is a procedure that uses strong magnetic fields and radiofrequency energy to make images of parts of the body, particularly, the organs and soft tissues like tendons and cartilage.
Both CT and MRI are painless, however, MRI can be more bothersome to some individuals who are claustrophobic, or suffer from anxiety or panic disorders due to the enclosed space and noise, the machine makes.
MRI costs more than CT, while CT is a quicker and more comfortable test for the patient.
Diverticulitis SlideshowDiverticulitis (diverticulosis) is a condition in which the diverticulum or diverticula rupture in the colon, causing infection. Medical treatments such as antibiotics and surgery can treat diverticulitis (diverticulosis).
How Fast Does Amoxicillin Work for a UTI?Learn how amoxicillin can help ease your urinary tract infection symptoms and help you manage this condition. Learn the symptoms of UTIs and kidney infections to better treat these conditions.
Kidney PainKidney pain has a variety of causes and symptoms. Infection, injury, trauma, bleeding disorders, kidney stones, and less common conditions may lead to kidney pain. Symptoms associated with kidney pain may include fever, vomiting, nausea, flank pain, and painful urination. Treatment of kidney pain depends on the cause of the pain.
STDs in MenSymptoms of sexually transmitted diseases (STDs) in men include painful urination, bumps or sores on the penis, and penile discharge and itching. Learn about the most common STDs in men.
Urinalysis (Urine Test)Urinalysis (urine test, drug test) is a test performed on a patient's urine sample to diagnose conditions and diseases such as urinary tract infection, kidney infection, kidney stones, and inflammation of the kidneys, or screen for progression of conditions such as diabetes and high blood pressure.
UTI Symptoms SlideshowBladder infections can be painful and often require medical treatment. Get the latest information on urinary tract infections (UTI) . Learn how UTI's are diagnosed in infants, adults, and the elderly.
Urinary Tract Infection QuizHow would you know if you had urinary tract infection (UTI)? Take the Urinary Tract Infection in Adult Quiz to learn the causes, symptoms, and treatments for infection that can affect your kidneys, ureters, bladder, and urethra.
Urine and HealthHave you been asked to provide a urinalysis sample? A urinalysis examines the cells and substances in your urine to search for disorders. Does urinalysis detect health problems like dehydration, lupus nephritis, liver problems, kidney stones, kidney infection, and bladder infection? Learn why doctors order urinalysis.
Douching (Vaginal Douche)Women douche for a variety of reasons, however, doctors and other healthcare professional do not recommend douching. Douching can change the vaginal flora, and make women more prone to vaginal infections. Health problems linked to douching include sexually transmitted diseases (STDs), pelvic inflammatory disease (PID), and vaginal irritation.