Urinary Tract Infection (UTI) is an infection of the urinary tract more commonly the urethra (urethritis) and the bladder (cystitis). When these are affected, it is called lower UTI. When the infection spreads upwards, then there is the involvement of the ureters (ureteritis) and the kidney (pyelonephritis). When ureters and kidneys are affected, it is called upper UTI, which is less common than lower UTI but can be more serious.
Nephritis (inflammation of the kidneys) is classified according to the part of the kidney involved. Pyelonephritis (part of the kidney emptying into the ureters) is caused due to the upward spread of infection from the bladder through the ureters and constitutes part of upper UTI.
Other types of nephritis are blood-borne from other sometimes distant sites of infection or inflammatory conditions. These do not come under UTI. These include glomerulonephritis (affecting the filtering part of the kidney – glomerulus), and tubulointerstitial nephritis (affecting the transporting/absorbing kidney tubules and the spaces between the tubules), which are not discussed here.
- Dysuria (difficulty in urination with burning pain)
- Frequency (urinating >7 times a day with not more than 2L water intake, or frequent urination disturbing daily routine or comfort)
- Urgency (strong and immediate uncontrollable need to urinate)
- Nocturia (waking up 2 or more times in the night to urinate)
- Discharge (sticky whitish fluid) from the urethra
- Pain in the pelvic area or lower abdomen (cystitis) or dull aching pain in lower back or flanks (nephritis)
- Fever (sometimes with chills), body pain, nausea/vomiting (more common in nephritis)
Dysuria is typically a sign of urethritis. Frequency, urgency, and nocturia are caused by inflammation and irritation of the urinary bladder, suggesting cystitis.
Women at greater risk
UTI is more common in women due to a short urethra and proximity to the anus. Risk increases in pregnancy, and in elderly especially around/after menopause. The risk is also higher after sexual intercourse, poor menstrual hygiene, and use of diaphragms or spermicidal creams/jellies/foam.
Poor Urination Habits and Hygiene
The tendency to hold urine for long before urinating, incomplete bladder emptying, and poor toilet hygiene, increase infection risk, as urine is a conducive medium for bacterial growth.
Diabetes increases the risk of UTI. Other conditions that reduce immunity like medicines (corticosteroids, anti-cancer drugs, etc.) or HIV, post renal transplant, also increase UTI risk. Spinal cord injuries can cause loss of bladder sensation/control, leading to abnormal urination, retention of urine, and risk of UTI.
Urinary tract structural and functional abnormalities
- stones (calculi)
- enlarged prostate
- lower urinary tract problems (LUTS)
- narrowing of urethra (stricture)
- congenital malformations (kidney abnormality since birth)
- reflux (backflow) of urine into the ureters from the bladder due to abnormal valvular function or entry positioning/mechanisms at the site of ureter entering into the bladder (vesicoureteral reflux VUR) seen more in infants/children).
- instrument use for diagnosis or procedure like urinary catheters, stents, tubes or cystoscope.
The most common bacteria to cause UTIs is Escherichia coli (E. coli) in 90% of cases. Other bacteria include Klebsiella, Proteus, Pseudomonas, and Staphylococcus, these being more common in people with low immunity, urinary tract abnormalities, and after instrumentation/procedures.
Because the vagina and urethra in women are so close together, bacteria that cause vaginitis can spread to the urethra and vice versa. Bacteria causing sexually transmitted diseases (STDs) can also sometimes cause UTI.
The diagnosis is made by the characteristic clinical symptoms. However, a urine test is also commonly ordered (which should be done so before starting antibiotics).
A first-morning mid-stream urine sample collected in a sterile disposable container is most appropriate for the test. UTI may impart the following signs to the urine –
- Cloudy urine with an unusual/foul odor
- Bacteria (+100,000/mL) – further urinary culture can reveal the causative bacteria, and their sensitivity to common antibiotics can also be ascertained. (Urine culture-sensitivity).
- Pus in urine (pyuria).
- Blood in urine (hematuria) – It could be visible blood in urine (macroscopic hematuria) or red blood cells (RBCs) seen on examination (microscopic hematuria).
- Urinary casts: white blood cells with lining cells of kidney (renal epithelial cells) present which suggests involvement of the kidney.
In some cases, CT/MRI imaging of kidney or cystoscopy to visualize urinary bladder may be needed.
- Drink plenty of water – at least 3-4 L/day and urinate frequently to flush out bacteria.
- Cranberry, blueberry, raspberry extracts/juices contain proanthocyanidin, which can prevent bacteria from adhering to the lining of the urinary tract. These have shown benefit in some studies, although more conclusive evidence is still needed.
- Avoid Carbohydrates, artificial sweeteners, high sugar drinks, soda and alcohol, caffeinated drinks, highly spicy foods, and citrus (acidic) fruits like oranges, lemons/lime, and grapes. Have more bananas, lentils and high fiber cereals.
- Probiotics (good friendly bacteria) supplements are also prescribed.
- Do not hold urine for too long, pass as soon as the desire arises, and after intercourse.
- Maintain hygiene and regular washing of urinary area. After urinating or passing stool, wipe from front to back with clean tissue/soft toilet paper, to prevent bacteria from anus coming into vagina or urethra. Avoid deodorant sprays in the urinary area.
- Discuss alternate contraceptive methods.
Antibiotics are the mainstay of treatment. Fluoroquinolone class drugs like ciprofloxacin, ofloxacin, norfloxacin and levofloxacin are usually the common antibiotics prescribed. Other antibiotics like amoxicillin-clavulanate, cephalosporin group, sulfamethoxazole-trimethoprim, and specific urinary antibiotics fosfomycin or nitrofurantoin are also prescribed in many patients. The treatment duration usually ranges from 3-7 days. Lower UTI is treated on an outpatient basis with oral antibiotics, however upper UTI involving kidney may require hospital admission and intravenous antibiotics and fluid support.
Medicines like flavoxate that relax the urinary bladder muscles, and reduce pain and bladder irritation may also be prescribed. Sometimes these are available in combination with antibiotics.
Urinary Tract Infections respond well to treatment and seldom cause long-term problems. In some cases especially with multiple risk factors and in women, they may be recurrent.
Recurrent UTI is defined as 2 or more UTIs within 6 months or 4 or more in a year. Recurrent or chronic pyelonephritis is associated with progressive renal damage and scarring, which can lead to chronic kidney disease (CKD), kidney failure, and end-stage renal disease (ESRD), requiring dialysis or transplant.
The term complicated UTI is used when any of the mentioned urinary tract structural and functional abnormalities, instrumentation, spinal injury, tumors, kidney failure or transplant are associated factors present. In these cases, the need for prolonged treatment and failure rate is higher.
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