Urinary Tract Infection

Urinary tract infection (UTI) is a common post-operative complication for various surgical procedures. Patients that develop UTIs in the peri-operative period have higher rates of mortality and longer lengths of stay, so it is important that they are promptly recognised and managed.

Risk Factors

There are several factors that increase the risk of developing post-operative urinary tract infection:

  • Age > 60yrs
  • Female
  • Significant comorbidities (e.g. cardiac failure, renal failure, pulmonary disease, or diabetes)
  • Catheterisation

Clinical Features

Fig 1 – Urine should be inspected for turbidity and urine dipstick performed

The classical clinical features of UTI are dysuria, frequency, offensive urine and urgency. The urine may be blood stained or cloudy. On examination, these patients often have mild suprapubic pain and be pyrexial.

A UTI should also be considered in the any patient who presents:

  • Septic (without a clear foci of infection)
  • With acute urinary retention
  • With delirium

It is also important to examine for signs of pyelonephritis (renal angle tenderness).


A urine dipstick should be performed initially for all suspected cases (despite a high rate of contamination seen in the elderly population). If the urine dipstick is positive (nitrites or leukocyte esterase ± blood), then a sample of the urine should be sent off for microscopy, culture and sensitivities (MC&S). These are usually referred to as a ‘mid-stream urine (MSU)’ or, if the patient is catheterised, a ‘catheter specimen of urine (CSU)’.

Fig 2 - Urine dipstick chart.

Fig 2 – A urine dipstick chart; detection of nitrites or leucocyte esterase are most specific for a UTI

Depending on the clinical picture, some blood tests should be considered:

  • FBC and CRP
  • Blood cultures (for any septic patient)
  • VBG (for an septic patient, looking at pH and lactate)

If the patient is also in retention, a bladder scan is usually indicated to measure bladder residual volume (retention is generally considered at a volume of >500mL).


Ensure the patient has a good hydration status (generally, this should be through oral intake but supplementary IV fluids can be prescribed if needed) and maintains a urine output of >0.5mL/kg/hour.

Definitive management is with antibiotics. Refer to your local antimicrobial prescribing guidelines for guidance on which antibiotic to choose; trimethoprim, nitrofurantoin, and co-amoxiclav are common antibiotic choice. Majority of UTIs will resolve from the empirical treatment, yet adapt accordingly following MC&S results if poor response.

Any catheterised patients with a suspected UTI should have their catheter changed prior to starting any antibiotics.


Question 1 / 5
Which of these is NOT a significant risk factor for a UTI?


Question 2 / 5
Which of these test results is most sensitive and specific for a UTI?


Question 3 / 5
How should urine be collected when testing for a UTI?


Question 4 / 5
What are the classical clinical features of a UTI?


Question 5 / 5
Which of the following is NOT part of routine management of a UTI?


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