In the United States, about 8.1 million health care visits each year are due to having a urinary tract infection, according to the National Kidney and Urologic Diseases Information Clearinghouse.
A urinary tract infection occurs when bacteria enters the individual’s urethra — the tube that transports urine from the bladder out of the body. Once the bacteria enters the urethra, it can spread to the bladder, and then to the kidneys.
In rare cases, the infection can affect the ureters, the area of the body that transports the urine from each of the kidneys to the bladder.
When a urinary tract infection is treated, the individual may not experience any complications. However, if the urinary tract infection is left untreated, several complications may occur.
Chronic or acute pyelonephritis, or a kidney infection, can occur when a urinary tract infection is not treated. Individuals who have either acute pyelonephritis or chronic pyelonephritis may develop permanent kidney scars.
These scars may lead to serious kidney problems, such as kidney failure and chronic kidney disease, according to the National Kidney and Urological Diseases Information Clearinghouse. High blood pressure may also occur.
In some cases of untreated urinary tract infections, the infection can spread to the individual’s bloodstream, called sepsis. Sepsis may also occur with pyelonephritis.
The risk for this complication is higher in individuals who have lowered immune systems, or those who are very old or young, according MedlinePlus. When an individual has developed sepsis, her blood pressure drops and her major organs stop working properly.
Symptoms include warm skin, chills, lightheadedness, fever or hypothermia, confusion and shaking. Hyperventilation, decreased urine output, skin rash and a rapid heartbeat may also occur.
Individuals with sepsis will be hospitalized for treatment.
Complications Specific to Pregnant Women
Women who are pregnant face additional complications for an untreated urinary tract infection.