What Is A Urinary Tract Infection?

A Urinary Tract Infection (also called UTI's) is an infection that starts in the urinary system of the body. The urinary system of the body is comprised of the kidneys, urinary bladder, the ureters, and the urethra. An infection can occur in any of the parts of the urinary tract, but most infections involve the bladder and urethra - the lower urinary tract.

While urinary tract infections are irritating and painful, there are serious problems if a urinary tract infection spreads to the kidneys, causing a condition known as "pyelonephritis."

Urinary infections are the second most common type of infection in the body - accounting for over 8 million visits to health care professionals each year.

Women, due to a shorter urethra than men, are at greater risk for developing UTI's.

Most UTI's are treated with antibiotics.

The Anatomy Of The Urinary System:

The urinary system (also known as urinary tract or excretory system) is an organ system that works to produce, store, and eliminate urine. The body uses nutrients from the food and liquids we ingest to maintain bodily functions and provide us energy. After our body has taken all the nutrients from the food, there are waste products left behind: solid and liquid. The liquid waste products are excreted by the urinary system.

Humans have two kidneys, two ureters, a urinary bladder and a urethra. Let's explore the structure and function of the urinary tract in more detail.

The kidneys are bean-shaped organs that lie in the abdomen just below the ribcage, close to the lumbar section of the spinal cord. The primary function of the kidneys is to filter out water-soluble waste products from the blood. The kidneys perform a multitude of other functions, including:

  • Concentrating urine
  • Regulating the electrolyte balance of the body through the influence of local and systemic hormones
  • Maintaining acid/base homeostasis 
  • Removal of urea, a waste product from protein-rich food

The kidneys are filled with tiny units that filter the blood called "nephrons" which are a ball of small capillaries (a glomerulus) and a small tube (a renal tubule). Urea, water, and other waste products form what we know as "urine" as it passes through the filtration system of the kidneys.

The urine travels from the kidneys down the ureters - two thin tubes approximately 8 inches long - into the urinary bladder. When muscles in the ureter tighten and relax it forces urine away from the kidneys and down into the urinary bladder. Minute amounts of urine are emptied into the urinary bladder every 10-15 seconds.

A kidney infection can develop if urine stands still inside the ureters or backs up into the kidneys.

The urinary bladder is a hollow organ shaped a bit like a balloon that sits in the pelvis, where urine is stored until it is excreted. In a healthy urinary tract, the bladder can easily hold almost 2 cups of urine for up to five hours. When the bladder is full, nerves within the bladder tell the brain that it's time to excrete the urine.

A circular muscle at the bottom of the bladder, called a sphincter, works to keep the urine within the urinary bladder until such time as it can be excreted.

What Causes A Urinary Tract Infection?

While the urinary tract is designed specifically to keep out bacteria and other microorganisms, occasionally bacteria is able to sneak through and cause an infection. Most urinary tract infections occur in women and affect the lower parts of the bladder - the urethra and the bladder.

The two most common types of urinary tract infections are:

  1. Cystitis - an infection of the bladder often caused by the bacterium Escherichia coli (E. coli) normally found in the GI tract of the body. Sexual intercourse can lead to cystitis, but you do not have to be sexually active to develop cystitis. Women, based upon the proximity of their urethra to the anus as well as the short distance from the opening of the urethra to the urinary bladder, are more prone to cystitis.
  2. Urethritis - an infection of the urethra can occur if GI bacteria spread from the anus to the urethra. Other causes of urethritis can be caused by STD's.

What Are The Risk Factors For A Urinary Tract Infection?

Certain people are more prone to UTI's. Risk factors for urinary tract infections include:

  • Women are more likely than men to have UTI's.
  • Women who use diaphragms and/or spermicidal jelly as birth control are more prone to UTI's.
  • Sexual Activity - women who are sexually active tend to have more UTI's.
  • Anatomical abnormalities of the urinary tract or blockages of the urinary tract (as is the case with kidney stones) can increase the risk for development of Urinary Tract Infections.
  • Catheterization - those who urinate via catheter are more prone to UTI's.
  • Immunosuppression - those who are immunocompromised, meaning their immune system isn't as effective at fighting off bacteria are more prone to UTI's.
  • People who have nerve damage or spinal cord injuries near the urinary bladder may have difficulties in emptying their bladder entirely - which can allow urine to sit in the urinary bladder and grow bacteria. 

What Are The Symptoms Of A Urinary Tract Infection?

Not all Urinary Tract Infections cause symptoms - some may be asymptomatic. If symptoms occur, they may include:

  • Persistent urge to urinate without presence of urine in urinary bladder
  • Burning sensation while urinating
  • Excreting small but frequent amounts of urine
  • Cloudy or blood-tinged urine
  • Urine that smells strongly
  • Women may experience pelvic pain
  • Men may experience rectal pain

The type and location of the infection may result in more specific symptoms:

Cystitis (Bladder Infection):

  • Pressure in the pelvis
  • Discomfort in the lower abdomen
  • Frequent and painful excretion of urine
  • Blood-tinged urine

Urethritis (Infection of the Urethra):

  • Burning with urination

Pyelonephritis (Kidney Infection):

  • Flank pain
  • Pain in the upper back
  • High fever
  • Nausea and vomiting
  • Shaking and chills

How Are Urinary Tract Infections Diagnosed?

There are a number of tests a physician will order if a UTI is suspected. These tests may include:

Urinalysis: A sterile urine sample is taken and sent to the laboratory to ascertain whether there are bacteria and/or red blood cells present within the urine.

Urine Culture: A urinalysis may be followed by a urine culture, in which the bacteria from the urine is grown in a laboratory to ascertain the exact bacteria that is causing the UTI.

CT Scan/Ultrasound: These imaging tests may be used if a person has frequent UTI's to determine if there is an underlying anomaly in a part of the urinary tract.

Cystoscopy: If a person has frequent UTI's, a long, thin tube with a lens, called a cytoscope, is inserted to visualize the structures of the urethra and bladder.

How Are Urinary Tract Infections Treated?

Antibiotics are the first line of defense used to treat urinary tract infections. The precise type of antibiotic, and length of time antibiotics are taken, depend upon the specific bacteria present in the urinary tract.

Symptoms of a UTI tend to resolve within a few days of antibiotic treatment. Complete all antibiotics as prescribed to ensure the infection is truly gone.

For particularly severe UTI's, IV antibiotics and a hospitalization may be necessary to ensure that the UTI is eradicated.

Alongside the antibiotic treatment, avoid drinks that may cause irritation to the bladder. These can include coffee, alcohol, caffeine, and citrus juices.

Use a heating pad with warm - not hot - pressure on your abdomen to minimize any abdominal discomfort.

Drink clear liquids to dilute urine and flush out the bacteria.

How Can I Prevent A Urinary Tract Infection?

There are ways in which one can reduce the risk of urinary tract infections. These include:

Drinking lots of clear liquids helps to both dilute the urine as well as ensure more frequent urination. This will aid in allowing harmful bacteria to be flushed out of the urinary tract before a UTI develops.

Use the bathroom and urinate after sexual intercourse.

Drink a large glass of water after intercourse to help flush the bacteria from the urinary tract.

Always wipe from front to back after a bowel movement to prevent the bacteria from the rectum from spreading to the urethra.

Do not use feminine products that can cause irritation. Deodorant sprays or other scented douches or powders can cause the urethra to become irritated.

Urinate as frequently as possible to ensure the urinary bladder is emptied.

Wear loose-fitting and cotton clothing, especially underwear. Tight fitting jeans or nylon underwear can trap moisture and allow for the growth of bacteria.

Switch from a diaphragm to another form of birth control, if you're finding that you have increased UTI's.

Related Resource Pages on Band Back Together:

Sexually Transmitted Infections

Interstitial Cystitis


Kidney Stones

Polycystic Kidney Disease

Additional Urinary Tract Infection Resources:

American Urological Association Foundation - world's leading nonprofit urological health foundation—and the official foundation of the American Urological Association. We partner with physicians, researchers, healthcare professionals, patients, caregivers, families and the public to support and improve the prevention, detection and treatment of urological diseases.

National Kidney and Urological Diseases Information Clearinghouse - is a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The NIDDK is part of the National Institutes of Health of the U.S. Department of Health and Human Services.

American Kidney Fund - leads the nation in providing charitable assistance to dialysis patients who need help with the costs associated with treating kidney failure