Recurrent Urinary Tract Infections

Overview

A urinary tract infection (UTI) is a bacterial infection of any part of the urinary system — the kidneys, ureters, bladder, or urethra. Most infections involve the lower urinary tract (bladder and urethra) and are caused by bacteria from the bowel, most commonly Escherichia coli.

Recurrent UTI is defined as three or more culture-proven infections within twelve months, or two or more within six months. In women, recurrent lower UTIs are relatively common and often arise in the absence of any structural abnormality. In men, however, recurrent UTI is unusual and should always prompt investigation to identify an underlying cause.

Symptoms

A typical lower urinary tract infection produces:

• Dysuria — burning or stinging on urination
• Urinary frequency and urgency
• Cloudy, offensive-smelling urine
• Haematuria (blood in the urine), which may be visible
• Suprapubic discomfort or pressure

When infection has ascended to the kidney (pyelonephritis), additional features include:

• Fever, chills, and rigors
• Loin or flank pain and tenderness
• Nausea and vomiting
• General malaise

Recurrent infections follow the same symptom pattern but occur repeatedly. Between episodes, the individual may be entirely well, or may notice persistent mild urinary symptoms suggesting an ongoing underlying issue.

Diagnosis

Confirming the diagnosis Each episode of suspected UTI should be confirmed by midstream urine (MSU) culture, which identifies the causative organism and its antibiotic sensitivities. Treating based on symptoms alone without culture risks missing resistant organisms and does not help identify underlying problems.

Investigating for an underlying cause — especially in men In men with recurrent UTI, the following investigations are arranged:

• Urine flow rate and post-void residual ultrasound — to identify incomplete bladder emptying due to BPH or other causes
• Ultrasound of the kidneys and bladder — to identify structural abnormalities, stones, or thickening of the bladder wall
• PSA and prostate assessment — chronic bacterial prostatitis can be a reservoir for recurrent lower UTI in men
• Flexible cystoscopy — to inspect the bladder for tumours, stones, diverticula, or other structural issues
• CT urogram — if upper urinary tract pathology (stone, obstruction, tumour) is suspected

Blood tests may include kidney function and, in the context of fever, inflammatory markers and blood cultures.

Treatment

Treating individual episodes Each acute UTI should be treated with an antibiotic chosen on the basis of culture and sensitivity results. A urine culture taken after completing the course of antibiotics (test of cure) may be recommended for men, after upper tract infections, or when the infection is caused by a resistant organism.

Treating the underlying cause The most important step in managing recurrent UTI is to identify and treat any underlying structural or functional cause:

• BPH causing incomplete bladder emptying — treated surgically or with medication
• Urinary stones — removed endoscopically
• Urethral stricture — treated by dilatation or urethroplasty
• Atrophic changes in postmenopausal women — vaginal oestrogen can reduce recurrence

Antibiotic prophylaxis In selected patients where recurrences remain frequent despite addressing underlying causes, low-dose prophylactic antibiotics may be prescribed to reduce the frequency of infection. This is a specialist decision based on the pattern of infections, causative organisms, and individual circumstances.

Supplements Cranberry preparations and D-mannose may provide a modest reduction in recurrence risk in women but have limited evidence in men and should not substitute for proper urological investigation.