How Dangerous Are Urinary Tract Infections in Older Adults?

A fellow caregiver asked...

How dangerous are urinary tract infections (UTIs) in older adults?

Expert Answer

Dr. Leslie Kernisan is the author of a popular blog and podcast at She is also a clinical instructor in the University of California, San Francisco, Division of Geriatrics.

A urinary tract infection (UTI) "“ common in older adults -- can vary in seriousness from a minor medical problem all the way to a life-threatening illness. A UTI is diagnosed when bacteria begin growing in the bladder (which is usually a sterile environment), and this bacterial growth affects the body. How dangerous a UTI becomes depends on the overall health of the affected person and on whether or not the bacteria spread from the bladder out to other parts of the body.

Many UTIs cause symptoms related to bladder irritation, such as burning with urination, blood in the urine, and sometimes fever and abdominal pain. Treating such a UTI with oral antibiotics usually results in quick improvement.

In older people, especially those with dementia, a UTI can cause delirium, which is a new worsening of the mental state. This can be dangerous because people with delirium are at risk for falling or otherwise hurting themselves.

UTIs become much more dangerous when they spread from the bladder into the bloodstream or to the kidney. An infection that has spread in this way can cause life-threatening low blood pressure and can also affect other organs in the body. Intravenous antibiotics are needed to treat these expanded UTIs.

UTIs are more likely to spread in this way in people who have weakened immune systems. This includes the frail elderly and people who are critically ill, as well as people with diseases such as cancer, diabetes, or HIV.

Important: There is a condition that tests like a UTI but isn't one, and it isn't usually a cause for concern in an older adult. Asymptomatic bacteriuria occurs when a urine culture grows bacteria even though the person never shows any symptoms. Asymptomatic bacteriuria has been found in up to 20 percent of women older than 80, and in up to 15 percent of men older than 75. Experts, including those at the Infectious Diseases Society of America, recommend only treating asymptomatic bacteriuria in pregnant women and in those about to have a urological surgery. Studies have shown that treating older people for asymptomatic bacteriuria doesn't reduce the number of future UTIs.