According to the National Institutes of Health, urinary tract infections cause an estimated 8.3 million physician visits every year. Some people do not have any symptoms, while others may have to urinate a lot, but in small amounts, have a burning pain when they urinate, or have urine which has a strong smell or is pink.
Looking at the urinary tract in the same order as the flow of urine, it is made up of two kidneys, two ureters, the bladder and the urethra. As explained by the University of Maryland Medical Center, urine is made within the kidneys as these organs filter water and waste products, yet keep a balance of salt within the blood. The ureters are the muscular tubes that carry the urine to the bladder, and once the bladder is full of urine, it leaves through the urethra.
What Causes a Urinary Tract Infection?
Eating too much salt does not cause a urinary tract infection; a high-salt diet is a risk factor for hypertension and coronary artery disease. Most urinary tract infections are caused by bacteria, especially by Escherichia coli, according to Kamaljit Singh, M.D., assistant professor of medicine at Rush University Medical Center, in the book “Current Diagnosis & Treatment: Nephrology & Hypertension.” The majority of the time, an infection occurs because the E. coli that normally inhabit the large intestines reach the urethra, multiply and then ascend the urethra to reach the bladder. Parasites, viruses and fungi are also capable of causing infections in the urinary tract.
Women have a shorter urethra than men and it is closer to the anus, the exit of the large intestines, which is why physicians hypothesize women have more urinary tract infections than men. In addition, there are bacteria in the vagina, so intercourse, spermicides and diaphragms increase the risk, according to Maxwell Meng, M.D., associate professor in the department of urology at the University of California at San Francisco in the book “Current Medical Diagnosis & Treatment.” The use of catheters is a risk factor since bacteria in the catheter can reach the bladder. A large prostate and kidney stones can block urine flow and cause an infection.
A high-salt diet can lead to high blood pressure and heart disease, but urinary tract infections can lead to sepsis, a the condition in which bacteria spread throughout the blood. If it cannot be stopped, sepsis can result in organ failure and even septic shock, which affects several organs. Urinary tract infections can also damage the kidneys, causing abscesses, stones and an infection within the kidneys called pyelonephritis. Repeated kidney infections can result in scarring, and this can result in high blood pressure after many years, explains Mark Knox, M.D., clinical associate professor in the department of family medicine at the University of Pittsburgh School of Medicine in the book “Current Diagnosis & Treatment in Family Medicine.”
- “Current Diagnosis & Treatment in Family Medicine”; Jeannette South-Paul, M.D., Samuel Matheny, M.D., Evelyn Lewis, M.D.; 2008
- “Current Diagnosis & Treatment: Nephrology & Hypertension”; Edgar Lerma, M.D., Jeffrey Berns, M.D., Allen Nissenson, M.D.; 2009
- “Current Medical Diagnosis & Treatment 2011”; Stephen McPhee, M.D., Maxine Papadakis, M.D.; 2011
- National Institutes of Health: Urinary Tract Infections in Adults
- University of Maryland Medical Center: Urinary Tract Infections