Urinary tract infection ( UTI) can be explained as an infection in any part of the urinary tract. Urinary tract consists of upper urinary tract and lower urinary tract.

Lower urinary tract infection

Lower urinary tract infection encompasses infections of the bladder and urethra and can exist with pain and burning during urination, Rate of occurrence of urination, urging, presence of white blood cells (WBCs) in the urine (pyuria), painful and difficult urination (dysuria) or sometimes even presence of blood in the urine(hematuria). fever is usually not present in lower UTI. Acute cystitis (inflammation of the bladder) may present with pain above the pubic bone. UTI is an inflammatory response of the urothelium to bacterial intrusion.

prostatitis is a prostatic infection whose symptoms are frequent urination, dysuria, groin pain, difficulty in urination and painful ejaculation.

Upper urinary tract infection

Upper urinary tract infection encompasses infections of the kidneys (pyelonephritis – inflammation of the kidney) and ureters. Upper UTI includes all symptoms of lower UTI plus some other symptoms like high fever, nausea or vomiting and back pain.

Causes of UTI

The most common source of Uti is Escherichia coli (E. coli) which are gram negative, anaerobic and rod-shaped bacteria. These bacteria are part of the lower intestinal region and can comfortably propagate from faeces to the bladder. Other causes include klebsiella pneumoniae, enterococcus, pseudomonas aeruginosa, staphylococcus saprophyticus and candida albicans.

Urinary tract infections are more recurrent in women where the urethra is much shorter.

Diagnosis of urinary tract infection

Urine dipstick

A urine dipstick tests positive for nitrites indicate bacteria in the urine. E. coli bacteria break down nitrates into nitrites.

A remarkable rise in leukocytes (white blood cells) can result from an infection of other cause of inflammation. Leukocyte esterase which is a byproduct of leukocytes is tested on a urine dipstick which shows the number of leukocytes in the urine.

Management (treatment) of lower urinary tract infection

An ideal initial antibiotic in the community would be –

Nitrofurantoin (avoid in patients with an eGFR less than 45)
Trimethoprim

Alternatives

Pivmecillinam
Amoxicillin
Cefalexin

Duration

3 days of antibiotics for simple lower urinary tract infections in women
5 to 10 days of antibiotics for immunosuppressed women or impaired kidney function
7 days of antibiotics for men, pregnant women

Management of upper urinary tract infection ( pyelonephritis)

Take first line antibiotics for 7 to 10 days

Cefalexin
Co-amoxiclav
Trimethoprim
Ciprofloxacin

In pregnancy

The antibiotic choices in pregnancy are

Cefalexin ( the ideal choice)
Nitrofurantoin ( avoid in 3rd trimester)
Amoxicillin
Trimethoprim ( avoid in first trimester as it works as folate antagonist)

Urinary tract infection