28th July 2023

Urinary tract infections (UTIs)

UTIs can be classified as lower or upper. Lower urinary tract infection usually refers to cystitis, with symptoms of urinary frequency and dysuria. Upper urinary tract infection implies ascending infection in the kidneys, i.e. pyelonephritis, which typically presents with loin pain, fever, rigours, and nausea/vomiting.

Enteric bacteria are usually the cause of infection in the urinary tract, with Escherichia coli implicated in over 50% of cases. A wide range of antibiotics are used for UTIs, with choice depending on the patient’s microbiological history and local epidemiology, meaning local guidance should always be consulted.

Diagnosis is made through urinalysis, with urine samples sent for microscopy, culture and sensitivities to confirm infection and help tailor antibiotic choice. Urinalysis is not a reliable diagnostic tool in elderly patients, who should be treated based on symptoms and laboratory confirmation.

Pregnancy is a risk factor for urinary tract infections, and the antibiotic choice is limited by adverse effects on the foetus, with trimethoprim an important contraindicated antibiotic to know.

Bacteria are often found colonising the urinary tract without causing infection, known as asymptomatic bacteriuria. It is increasingly recognised that this finding does not require treatment, except in special populations such as pregnant women, men, and potentially renal transplant patients.

In men, prostatitis can cause exquisite pain on sitting or rectal examination. The same urinary pathogens cause it as UTIs but require extended treatment, usually for 14 days with ciprofloxacin.