Pathophysiology of Urinary Tract Infection: How Infections Affect the Organs of the Urinary System

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Causes and Risk Factors

A urinary tract infection, or UTI, can effect all parts of the urinary system such as the kidneys, urethra and bladder. A UTI is most often caused by a bacterial infection. They are somewhat rare in children, but are common in adults, especially women.

If the UTI affects the kidneys and the ureter, the condition is usually referred to as pyelonephritis. If the UTI affects the bladder, it is usually referred to as cystitis. However pyelonephritis is usually considered to a more serious medical condition than cystitis. UTIs are usually treated and cured with antibiotic therapy. However urinary tract infections if not properly managed can become recurrent.

Bacteria, the most common cause of UTIs, can come from a variety of sources. Poor hygiene can often be the cause of a urinary tract infection. Another common cause for a urinary tract infection is an obstruction in the urinary tract leading to urine not being completely cleared or emptying from the urinary tract properly. This old urine can then promote bacteria growth and eventually cause a urinary tract infection.

Many people with severe medical conditions such as diabetes are more susceptible to urinary tract infections. Another culprit for recurrent UTIs is not completely clearing the bacteria from the first infection. Many people stop their antibiotic therapy before the bacteria is completely cleared from their systems causing recurrent infections.

The urethra in a woman is much shorter than in men making women much more susceptible to UTIs than men, especially bladder or cystitis infections. Women are also more susceptible to infection because of menopause which thins the lining of the urinary tract because of a decrease in estrogen. Another factor for infection is the close proximity of the vagina in women causing cross contamination.

If left untreated a urinary tract infection can advance into the upper urinary system and cause more severe complications. Pyelonephritis or kidney infections if left untreated can cause permanent kidney damage.

Severe upper urinary tract infections like that caused by obstructions such as in the ureters are life threatening if not treated immediately.

Recurrent UTIs can cause kidney scarring, which can overtime lead to kidney failure. People with frequent upper urinary tract infections may develop serious kidney disease making them predisposed to many other medical conditions.


UTI symptoms include:

  • Pain or burning sensation during urinating
  • Abdominal discomfort, especially in lower region
  • Pressure sensation in pelvic region
  • Fever
  • Frequent need to urinate
  • Bloody or dark colored urine
  • Strong odor or foul smelling urine
  • Chills
  • Back pain
  • Nausea or vomiting
  • Weakness, fatigue

Kidney infection symptoms include:

  • High fever
  • Chills
  • Nausea and vomiting
  • Pain or discomfort under the ribs or in the upper portion of the back


Understanding the pathopsyiology of urinary tract infection symptoms is the first step leading to their prevention and treatment.

Maintain good hygiene at all times, especially after having sexual intercourse. Stay away from urethra irritation products, such as scented feminine or bath products. Always wipe front to back if you are a woman so as not to contaminate the urethra area. Maintain good hydration, an important factor for many body functions, is the best way to keep your urinary tract clean from bacteria. Do not hold your urine for long periods of time, as holding your urine can cause bacteria to sit in your bladder. Refrain from taking baths, take showers as much as possible.

If you think you may have any urinary tract problems you should see a medical doctor as soon as possible. Early treatment and diagnosis is the best way to cure any urinary tract infection and keep from having recurrent problems.