Monday, January 30, 2012

Urinary tract infection


Inflammation of the urinary tract (bladder, urethra, prostate or kidney) is called urinary tract infection (UTI). The most common site of infection is the bladder. The normal urinary tract is sterile above urethra. UTI can present with or without symptoms. The pathogenic microorganism may be present in the urinary tract for several months or even years without symptoms.

Factors that contribute to cause urinary tract infection (UTI):
Bacteria in urine is the main cause of UTI. The normal bladder is capable of clearing itself from a large number of bacteria in two days. An infection occurs when the bacteria accesses the bladder, attaches, colonizes the epithelium of the urinary tract and is not washed out by voiding. They evade the host's defense mechanism and initiate inflammation.

Women are more prone to UTI than men because of the close proximity of urethra and anus. The majority of infections result from fecal organisms that ascend from the perineum to the urethra and bladder, and adhere to the mucosal surface. Pregnant women are even more prone to get UTI because of their urge to urinate frequently and incontinence. Poor hygiene after sexual intercourse is another important cause of UTI in women.

Men suffer UTI less frequently than women. The incidence of UTI increases with age and disability. Escherichia coli, Staphylococcus saprophyticus, Streptococcus faecalis, Proteus mirabilis and one or more species of Klebsiella, Enterobacter, Pseudomonas are the organisms that cause UTI.

Those with structural abnormalities of urinary tract, neurogenic bladder secondary to stroke or accident, or with autonomic neuropathy of diabetes will have inability to empty bladder completely. This is another important cause of UTI.

Elderly or post menopausal women are susceptible to colonization and increased adherence of bacteria to the vagina and urethra in the absence of estrogen. This is because of the poor glycogen content of epithelial cells and decrease in acidic pH.

Men become equally at risk as that of women when they reach their 50's. Prostatic hyperplasia or carcinoma, strictures of the urethra and neuropathic bladder are the other reasons of UTI in men.

The use of catheterization or cystoscopy (by not following aseptic measures) to evaluate and treat diseases of the urinary tract will also lead to UTI. Unconscious, stroke or comatosed patients, patients with fractured femur (those not ambulatory) or those who have undergone major surgeries are catheterized for longer time and they acquire infection through the indwelling catheter.

Men with confusion or dementia and those with bowel and bladder incontinence tend to have chronic bacterial UTI's because of the presence of residual urine or stasis of urine in bladder.

Urethrovesicle reflux is another important cause of UTI. The urine from the urethra flows back into the bladder bringing bacteria to bladder from urethra. This can happen with coughing, sneezing or straining.

Poor hygiene due to lack of knowledge is another reason for UTI. The urethra should be wiped first after urination or defecation (from front to back). Wiping from anus to urethra brings microorganisms from anus to the urethra and finally ascend.

Poor intake of fluids results in concentrated urine and stasis which again harbors bacteria and causes UTI. Bladder should be emptied every four hours to prevent UTI.

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