Urinary Tract Infection (UTI): A Junior Doctor’s Guide

Introduction

Urinary tract infections (UTIs) are a common cause of hospital presentations, particularly in women, the elderly, and catheterized patients. They range from simple lower UTIs (cystitis) to more severe infections involving the upper urinary tract (pyelonephritis). Junior doctors should be adept at recognizing the signs, asking the right questions, and providing timely treatment to prevent complications. This guide provides a structured approach for managing UTIs, from history-taking to investigations and treatment.

History Taking in UTI

When evaluating a patient for a possible UTI, it’s essential to ask focused questions to differentiate between lower and upper UTIs and identify potential risk factors for complications.

Key Questions to Ask:

·     Presenting Symptoms:

·      Dysuria (painful urination): Ask if the patient has a burning sensation or pain during urination.

·      Urinary frequency and urgency: Is the patient going to the bathroom more often or feeling an increased urge to urinate, even with small amounts?

·      Suprapubic pain or discomfort: Any lower abdominal pain?

·      Hematuria: Has the patient noticed blood in their urine?

·      Nocturia: Is the patient waking up at night to urinate?

·     Symptoms Suggesting Upper UTI (Pyelonephritis):

·      Ask about fever, chills, or rigors.

·      Check for flank pain or costovertebral angle tenderness.

·      Ask about nausea, vomiting, or systemic malaise.

·     Sexual History and Risk Factors:

·      Recent sexual activity: Sexual intercourse, particularly in women, can increase the risk of UTIs.

·      New sexual partner: This may increase susceptibility to infections.

·      Use of contraceptives: Diaphragms and spermicides can predispose to UTIs.

·      Ask if the patient is pregnant, as UTIs can pose risks to both the mother and fetus.

·     Past Medical History:

·      Previous UTIs: A history of recurrent UTIs may change your approach to management.

·      Known urinary tract abnormalities or kidney stones: These can predispose to infection.

·      Diabetes mellitus: Diabetic patients are at increased risk of complicated UTIs.

·      Urinary catheterization: Prolonged catheter use is a common risk factor for UTIs.

·     Medication History:

·      Ask if the patient is on any immunosuppressive drugs or recent antibiotics, which may predispose to infections or alter treatment choices.

Examination Findings in UTI

A focused physical examination is crucial in assessing the severity of a UTI and ruling out complications such as pyelonephritis or sepsis.

·     General Appearance:

·      Does the patient appear unwell or septic (fever, tachycardia, hypotension)?

·      Look for signs of dehydration, especially in elderly patients.

·     Vital Signs:

·      Fever: Common in upper UTIs, but less frequent in lower UTIs.

·      Tachycardia: May be present if there is systemic infection.

·      Hypotension: A red flag for sepsis.

·     Abdominal Examination:

·      Suprapubic tenderness may be present in lower UTIs.

·      Costovertebral angle (CVA) tenderness (pain on palpation of the lower back) suggests pyelonephritis or kidney involvement.

·     Genitourinary Examination (if appropriate):

·      In sexually active patients, consider examining for signs of sexually transmitted infections (STIs), especially if the presentation is atypical.

·      In catheterized patients, check for signs of infection around the catheter site.

Investigations for UTI

Investigations help confirm the diagnosis and rule out complications.

·     Urinalysis (Dipstick Test):

·      Leukocyte esterase: Positive in most UTIs due to the presence of white blood cells.

·      Nitrites: Produced by certain bacteria (e.g., E. coli), a positive nitrite test is highly suggestive of a bacterial UTI.

·      Hematuria: May indicate inflammation or infection of the urinary tract.

·     Urine Microscopy and Culture:

·      Midstream urine (MSU) sample for culture: Essential for confirming the diagnosis and identifying the causative organism. This is particularly important in complicated UTIs, pregnant women, or treatment failure.

·      Sensitivity testing will guide antibiotic choices.

·     Blood Tests:

·      Full blood count (FBC): Look for leukocytosis, which may indicate a more severe infection.

·      Renal function tests (urea, creatinine, electrolytes): Evaluate renal involvement, particularly in pyelonephritis or septic patients.

·      Blood cultures: Consider if there are signs of sepsis or in cases of severe pyelonephritis.

·     Imaging (if indicated):

·      Consider a renal ultrasound or CT KUB (kidneys, ureters, bladder) if there is suspicion of urinary tract obstruction, recurrent infections, or failure to respond to treatment. This can help detect stones, abscesses, or structural abnormalities.

Management of UTI

The management of UTI involves antibiotics, supportive care, and addressing underlying or precipitating factors.

·       Simple Lower UTI (Cystitis):

• First-line antibiotics (according to local guidelines):

• Nitrofurantoin 100 mg BD (twice daily) for 3–5 days.

• Trimethoprim 200 mg BD for 3 days (unless contraindicated, e.g., pregnancy).

• Pivmecillinam 400 mg TDS (three times daily) for 3 days.

• Advise the patient to stay hydrated to flush the urinary system.

• Consider analgesia (e.g., paracetamol or ibuprofen) for symptomatic relief.

·       Upper UTI (Pyelonephritis):

• Antibiotics: Longer courses (7–14 days) of antibiotics are needed. Use broader spectrum antibiotics such as:

• Ciprofloxacin 500 mg BD for 7–10 days.

• Co-amoxiclav 625 mg TDS for 7–10 days.

• If there is concern about sepsis, consider IV antibiotics (e.g., cefuroxime or gentamicin).

• Hospital admission may be required for:

• Patients who are septic or have signs of shock.

• Patients unable to take oral medications due to nausea/vomiting.

• Pregnant women, the elderly, or those with significant comorbidities.

·       Complicated UTI:

• Complicated UTIs (e.g., in diabetics, pregnant women, or catheterized patients) often require longer courses of antibiotics and a tailored approach based on urine culture results.

• Pregnancy: Nitrofurantoin (avoid in 3rd trimester), cephalexin, or amoxicillin can be used safely. Avoid trimethoprim unless folate deficiency is ruled out.

• In catheterized patients, consider catheter change if the catheter is suspected to be the source of infection.

·       Recurrent UTIs:

• Address underlying causes: Consider urological referral if anatomical abnormalities or stones are suspected.

• Prophylactic antibiotics may be considered in patients with recurrent UTIs, especially in postmenopausal women or those with recurrent infections associated with sexual activity.