Urinary Tract Infection - Risk Factors

Anatomical Abnormalities in Adults

Some people have structural abnormalities of the urinary tract that cause urine to stagnate or flow backward into the upper urinary tract. Such conditions include the following:

A prolapsed bladder (cystocele) can result in incomplete urination so that urine collects, creating a breeding ground for bacteria.
Tiny pockets called diverticula sometimes develop inside the urethral wall and can collect urine and debris, further increasing the risk for infection.

Click the icon to see an image of a cystocele.

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Antibiotics as Risk Factors for UTIs

Antibiotics often eliminate lactobacilli, the protective bacteria, along with harmful bacteria. This causes an overgrowth of E. coli in the vagina. In one study, the risk for UTI increased during the 15 to 28 days that women were taking antibiotics. In fact, some research suggests that taking antibiotics for a urinary tract infection increases the risk for a subsequent infection.

Medical Conditions That Increase the Risk for UTIs

Diabetes. Diabetes puts women (but not men) at significantly higher risk for asymptomatic bacteriuria. The longer a woman has diabetes, the higher the risk. (Control of blood sugar has no effect on this condition.) The risk for UTI complications is also higher in people with diabetes. In fact, certain UTI-related abscesses are reported only in patients with diabetes. These patients are also at higher risk for fungal-related UTIs.

Kidney Problems. Nearly any kidney disorder increases the risk for complicated UTIs.

AIDS and Immunosuppressed Patients. Any infection is dangerous in people whose immune systems are damaged, and UTIs are no exception, particularly pyelonephritis.

Sickle-Cell Anemia. Patients with sickle-cell anemia are particularly susceptible to kidney damage from their disease, and UTIs put them at even greater risk.

Kidney Stones. In some cases, kidney stones can cause urinary tract obstruction that leads to infection, particularly pyelonephritis. Symptoms of severe urinary tract infection in people with a history of kidney stones may indicate obstruction, which is a serious condition.