Urinary Tract Infection & Pyelonephritis

Objectives

To guide the management of patients presenting with lower urinary tract infections (UTIs) across all levels of care. 

Scope

This guideline outlines the initial investigations and general management of urinary tract infections and pyelonephritis. For guidance on sepsis related to urinary tract infections, see also the immediate management of sepsis CGO.

Audience

This guideline is intended for the use of registered healthcare professionals fulfilling a general role in a forward medical location or in an Emergency Department on deployed operations.  

Initial Assessment & Management

For simple UTI

Presenting features

Common signs of a urinary tract infection include dysuria (often described as a burning sensation during micturition), urgency or frequency, and supra-pubic discomfort. The patient may also described urine as being cloudy or strong-smelling, and may experience fever. Flank or back pain is an indicator of possible renal involvement (pyelonephritis) - see below.

Older patients, especially, can present with fever and/or confusion and may not initially describe urinary symptoms. Urinalysis is not recommended in patients >65 years as the test is poorly specific.

Self care  

• Advise the use of self-administered or prescribed simple analgesia such as paracetamol or ibuprofen.  

• Encourage the patient to drink enough fluid to avoid dehydration.  

Investigations 

• Perform bedside urine dipstick testing. UTI is likely if positive for: 

Nitrite or leucocyte and red blood cells 

Nitrite and leucocyte 

• Obtain mid-stream urine (MSU) sample and send for laboratory culture and susceptibility testing (if facilities are available.) 

Antibiotic management 

• Consider previous urine culture sensitivity results (if available) and prescribe as per sensitivities. 

• Otherwise give antibiotics in accordance with current DMS antimicrobial guidance. 

• Once urine MSU results are available, review the antibiotic choice and change as appropriate. 

• Use a narrow spectrum antibiotic whenever possible. 

Antibiotic choice can be affected by pregnancy - check DMS antimicrobial advice for appropriate treatment.

Pyelonephritis

Suspect if urinary symptoms are accompanied by flank pain and fever, or if the patient has nausea/vomiting with lower urinary tract symptoms. Alongside urinalysis, check for pregnancy in all women of child-bearing age.

Assess for signs of sepsis including altered mental state, tachypnoea (>20), hypotension (systolic <100mmHg), tachycardia (>90), anuria (>12 hours), mottled or ashen skin - follow the guidance in the immediate management of sepsis CGO if identified.

Patients who are not septic but who are significantly dehydrated, who are pregnant, who have severe flank or abdominal pain, or who have a high fever (>39.4°C) should be treated with intravenous antibiotics, started on intravenous fluids if unable to take adequate volumes orally, and should be evacuated to a higher level of care as a priority.

Otherwise patients being managed locally should be treated with oral antibiotics and simple analgesia while encouraging oral hydration, and must be reviewed regularly to monitor for worsening pain or other deterioration; improvement is expected within 48 hours of starting antibiotics - consider other possible diagnoses and likely need to reach back for specialist advice or evacuation for investigation if no improvement is seen.    

Advanced Assessment & Management

Ensure all actions outlined in 'Initial Assessment & Management' (above) have been completed.

Send mid-stream urine sample for laboratory culture and susceptibility testing (if facilities are available), ideally before antibiotics are commenced.

If pyelonephritis is suspected then treat as above, and additionally check renal function. If impaired then treat with intravenous fluids in addition to intravenous antibiotics, and both escalate for critical care input and reach back for specialist advice (when possible) if impairment is moderate or severe.

Prolonged Casualty Care

Simple UTI is unlikely to cause challenges with prolonged casualty care, and it should be anticipated that personnel can return to their duties if systemically well. Most cases resolve within days once treatment has commenced. Duties can be continued whilst receiving treatment at the discretion of the treating clinician, depending on the severity of the patient’s symptoms, their systemic response and analgesic requirements. 

A clinician should be vigilant to a UTI that doesn’t respond to antibiotics and consider alternative pathology (see Differential Diagnoses section below). 

Remind the patient to present for reassessment if: 

• Symptoms do not improve within 48 hours of starting treatment 

• Worsening abdominal pain 

• Loin pain 

• Haematuria 

• Systemic “flu-like” illness 

• Urethral or vaginal discharge 

• Developing or worsening testicular pain.

In any patients presenting for review on this advice, consider an alternative diagnosis and escalation of care through the operational patient care pathway. 

Patients with suspected pyelonephritis who meet the criteria for evacuation described above should be treated with ongoing intravenous antibiotics and fluids if evacuation is delayed or impossible. Monitor the patient for evidence of sepsis and follow the immediate management of the septic patient guideline if there is a deterioration.

Paediatric Considerations

Self-care  

• Advise the use of self-administered or prescribed simple analgesia such as  paracetamol or ibuprofen.  

• Encourage the patient to drink enough fluid to avoid dehydration.  

Antibiotic Management  

• Refer to specific DMS antimicrobial guidance and/or BNF for children for prescribing guidance in paediatric patients. 

• Consider previous urine culture sensitivity results (if available) and prescribe as per sensitivities. 

• Otherwise give antibiotics in accordance with current antimicrobial guidance. 

• Once urine MSU results are available, review the antibiotic choice and change if necessary. 

• Use a narrow spectrum antibiotic whenever possible.