Urinary tract infections occur when bacteria is present within the urinary tract in significant numbers. UTIs are common in women, with 1 in 5 adult women aged 20-65 experiencing a UTI at least once a year. Approximately 50% of women will experience UTIs at least once in their life.
Cystitis (bladder infection) makes up the majority of these infections. Involvement of the upper urinary tract (pyelonephritis) is less common compared to that of cystitis but can be associated with more serious complications.
The onset of UTI can be associated with one or more of the following symptoms:
About 25 percent of women with acute cystitis develop recurrent UTIs. Most recurrent infections are from bacteria present in the faecal or periurethral reservoirs. Some strategies can be undertaken to reduce the risk of recurrent infections.
1. Lifestyle changes
2. Prophylactic antibiotics
3. Treatment of any existing structural abnormalities
4. Treatment of any vaginal/lower genital tract infection
In most cases of uncomplicated cystitis the Escherichia coli is involved. This bacteria is present in 70-95 percent of both upper and lower UTIs. Other common pathogens are Enterococcus faecalis, Klebsiella species, Proteus species and yeast.
The largest group of patients with UTIs is that of adult women. Women are more prone to UTIs than men because in females, the urethra is much shorter and closer to the anus.
Other predisposing factors include:
1. Menopause Rates of UTIs are higher in postmenopausal women for a few reasons. For one, the presence of bladder or uterine prolapse can cause incomplete bladder emptying and stasis (reduced or stoppage flow) of urine which in turn promotes the growth of pathogens. Also, the loss of oestrogen after menopause leads to changes in the vaginal flora, especially the loss of lactobacilli, and increases your susceptibility to infection.
2. Sexual activity UTIs are very common in women aged 18-30 years as it is associated with coitus (the so-called ‘honeymoon cystitis’). In this age group, sexual intercourse is the cause of 75 to 90 percent of bladder infections, with the risk of infection being related to the frequency of sex. The use of spermicides and diaphgrams for contraceptive purposes further increases the risk of UTIs as it causes a change in the vaginal flora and eradication of the vaginal lactobacilli.
3. Recent instrumentation of the urinary tract (e.g. catheterisation, cystoscopy, urodynamic studies) The insertion of foreign instruments into the urinary tract promotes the translocation of bacteria colonised around the peri-urethral area into the bladder and other parts of the urinary tract. This increases the risk of developing bacteruria (presence of bacteria in the urine) in significant numbers eventually leading to a UTI.
4. Foreign bodies (e.g. catheters, urinary stones) Urinary catheters are the most important risk factors for bacteriuria. Catheters introduce organisms into the bladder and promote colonisation by providing a foreign surface for bacteria to adhere to and by causing irritation of the bladder mucosa. 80 percent of UTIs that occur while in hospitals or healthcare institutions are related to urethral catheterisation, and 5-10 percent are related to manipulation of the genito-urinary tract. Urinary stones similarly irritate the bladder as well as provide a nidus for bacteria to adhere to, thereby increasing the risk of developing a UTI.
5. Neurological disorders, drugs or pelvic organ prolapse These conditions may cause incomplete emptying of the bladder, thereby promoting stasis of urine which increases the risk of UTI development.
6. Medical conditions (e.g. diabetes) Diabetes leading to glycosuria (sugar in the urine) makes for fertile breeding ground for bacteria. A study showed that 9.4 percent of patients with Type 2 diabetes had a UTI compared to only 5.7 percent of people without diabetes.
The diagnosis of a UTI can be suspected from a well-taken history and physical examination.
Specific tests to confirm a UTI include a urine dipstick, urine analysis and urine culture. The main emphasis lies with the detection of pyuria (white blood cells or pus cells in the urine) on dipstick and urine analysis. Associated findings can include microscopic haematuria (blood in the urine which cannot be detected by the naked eye). A urine culture will help in the identification of the organism causing the infection.
No imaging studies are indicated in the routine evaluation of an uncomplicated cystitis.
Empirical antibiotics are usually prescribed for UTIs. The patient may be prescribed alternative antibiotics after the urine culture results are available. The duration of treatment of the UTI depends on the antibiotic in use. Some common first-choice agents for the treatment of uncomplicated cystitis in women include nitrofuratoin, bactrim or beta-lactams such as cephalexins.
Most patients can be treated on an outpatient basis. However, hospital admission for management of complicated UTIs may be indicated in some patients. Complicating factors include the presence of structural abnormalities (e.g. stones, indwelling catheters), metabolic disease (e.g. diabetes, pre-existing kidney disease) or patients who are immunosuppressed and therefore more prone to serious infections (e.g. HIV, patients on chemotherapy).
Recurrent UTI is defined as having UTI three or more times in a year. This can be due to the same or different bacteria. In these cases, further investigations may need to be done, e.g. renal ultrasound, intravenous pyelogram, cystoscopy, urine for tuberculosis and cytology, to look for any underlying causes and complications of recurrent UTIs.
Patients with recurrent UTI may be given prophylactic antibiotics for a period of six months. They will also be advised on the various preventive measures and the importance of keeping good personal hygiene.
The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.
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