Infectious Disease and Your Kidneys

August 12, 2014, 10:06am EDT

Infectious DiseaseWhat would you do if you had a fever with irritation or pain when you urinate? Would you wait a few days and then make an appointment to see a doctor? Don’t wait. Those symptoms might be from a bladder infection. Bladder infections need to be treated. If a bladder infection is not resolved, it may lead to a kidney infection.

Kidney infections are rare, but they can cause a number of problems. Urine is one of the body fluids that normally have no bacteria. When the bladder is infected with bacteria, the bacteria in the bladder can travel up to the kidney. If this happens, you may have pain in the back or side, chills and fever, irritation or pain when urinating, or orange–colored urine (a sign of blood in the urine). Nausea and vomiting can also occur. Urine is checked for bacteria in several ways. A test of the kidney, such as a scan or an ultrasound may be ordered. A kidney infection is called pyelonephritis.

Most kidney infections start as bladder infections. Bladder infections usually get better with antibiotics in otherwise healthy people. The goal of antibiotics is to kill the bacteria in the bladder and prevent it from spreading. One dose is not enough; you need to finish all of the pills in the prescription to be sure the bacteria are gone. If you still have symptoms when you finish the pills, you should call your doctor. You might need another or a different prescription.

People with diabetes or other health problems may need several prescriptions to get rid of the bacteria. Some people develop a chronic infection of the kidney that is very stubborn and hard to get rid of. A continuing problem with a kidney infection is called chronic pyelonephritis. Having a severe kidney infection or repeated kidney infections can damage the kidneys. They can lead to chronic kidney disease. If you have a severe kidney infection, your kidney function will be closely watched even after it has been treated. You will have regular tests to check the glomerular filtration rate (GFR). The GFR shows how well the kidneys are functioning.

Your kidneys filter waste from your blood, before returning the blood to the rest of your body. If you have bacteria in your kidneys, the bacteria can spread during the filtering process. This can cause bacteria to be sent back to the bloodstream, and is another serious complication of kidney infection. An infection in the blood stream is called sepsis. Sepsis is very dangerous. Fortunately, this is rare.

Remember, any sign of pain when you urinate can be a sign of a bladder infection. And, back pain isn't always pain from the muscles or bones in the back. It can be pain from a kidney infection. If you have these symptoms, or any sign of discomfort when you urinate, call your doctor.

Bladder Infections Are Common

Kidney infections are a rare complication of bladder infections. Bladder infections are very common, though. In fact, about half of women will have one in their lifetime. Those most at risk are women who are younger than 50. Women have a greater risk than men because of their anatomy. The tube that carries urine from the bladder to the outside (urethra) is shorter in women. And the urethra is closer to the bowels. While only one in 10 men will have a urinary tract infection, bladder infections in men are more likely to occur later in life. Older men are more likely to have prostate problems, which can partially block the urine.

Other, more unusual, causes of kidney infections are medical procedures that require a scope of the bladder or surgery of the urinary tract. Urinary tract infections can be caused by bacteria that come in from catheters. Catheters are tubes that drain urine from the bladder. Urinary catheters are tubes used in people who are having problems urinating or during medical procedures. Other causes of infections are blockages from prostate enlargement or kidney stones.