Complicated urinary tract infections occur in men and women of all ages and are caused by bacteria that affect one or more parts of the urinary tract—the kidneys, ureters, bladder and urethra. Complicated urinary tract infections are more severe and more difficult to treat, and are recurrent. They are often the result of metabolic, functional, or structural abnormalities in the urinary tract that impair the ability of the urinary tract to clear out urine and any bacteria it may contain. If the structural abnormality is not corrected, they may recur or become chronic.
Complicated urinary tract infections can also occur when someone has had recent instrumentation or surgery of the urinary tract where they had a catheter and were exposed to various types of bacteria and they occur when someone has what is known as a comorbidity (another condition) that increases the risk for acquiring infection or resistance to treatment, such as poorly controlled diabetes, chronic kidney disease or being immunocompromised as in HIV.
The risk of complicated urinary tract infections is higher for people with diabetes and with nearly any kind of kidney disorder, including kidney stones.
If left untreated, urinary tract infections can develop into very serious and potentially life-threatening kidney infections (pyelonephritis) that can permanently scar or damage the kidneys. The infection can also spread into the bloodstream and elsewhere in the body. This is called sepsis.
Recurrent urinary tract infections that scar the kidneys, can lead to renal hypertension and eventual kidney failure over time.
Treatment with appropriate antibiotic therapy is determined by the type of bacteria that caused the infections, the severity of the infection and the site of the infection and see a kidney specialist if you experience fluid retention in your legs, ankles, feet or face; have unexplained fatigue, headache, nausea or vomiting.