Urinary tract infections in women

Urinary tract infections in women

Urinary tract infections (UTI) are one of the most common acute reasons for women to present in general practice, and for many women they are a recurrent misery.¹ Most people who consult a healthcare professional about a UTI will be prescribed an antibiotic, although of those who have a urine sample sent for culture, only 24-66% have a confirmed bacterial infection.^2,3

Urinary tract infections (UTI) is an infection of the bladder (also known as cystitis), usually caused by bacteria from the gastrointestinal tract.

• Uncomplicated UTI – UTI cause by typical pathogens in people with a normal urinary tract and kidney function, and no predisposing comorbidities
• Complicated UTI – UTI with an increased likelihood of complications such as persistent infection, treatment failure ad recurrent infection.

Risk factors for complicated UTI include structural or neurological abnormalities of the urinary tract, urinary catheters, virulent or atypical infecting organisms and comorbidities such as poorly controlled diabetes or immunosuppression.

Definitions

• Lower UTI is an infection of the bladder.
• Cystitis is often used as a synonym for lower UTI (particularly for women), although technically it means 'inflammation of the bladder' and there may be rare, non-infectious causes such as radiation and chemical-induced cystitis.
• Upper UTI includes pyelitis (infection of the proximal part of the ureters) and pyelonephritis (infection of the kidneys and the proximal part of the ureters).
• Uncomplicated UTI is infection of the urinary tract by a usual pathogen in a person with a normal urinary tract and normal kidney function.
• Complicated UTI is when one or more risk factors present that predisposes the person to persistent infection, recurrent infection, or treatment failure.
• Recurrent UTI is repeated UTI, which may be due to relapse or reinfection, and may be defined as 3 or more UTIs in the last 12 months, or 2 or more episodes of confirmed UTI in the last 6 months.
• Relapse is defined as a recurrent UTI with the same strain of micro-organism. Relapse is the likely cause if infection recurs within a short period after treatment (for example within 2 weeks).
• Reinfection is a recurrent UTI with a different strain or species of micro-organism. Reinfection is the likely cause if UTI recurs more than 2 weeks after treatment.
• Asymptomatic bacteriuria is the presence of significant bacteria in the urine, as a result of colonisation of the urinary tract, without symptoms or signs of infection.⁴

CAUSES OF UTI

UTI is usually caused by bacteria from the gastrointestinal tract, most commonly Escherichia coli which causes 80% of cases.^5,6

Entry of bacteria to the urinary tract can be:

• Retrograde – bacteria ascend through the urethra into the bladder.
• Via the blood stream (more likely in immunocompromised people)
• Directly, for example, from insertion of a catheter into the bladder, instrumentation or surgery

Less commonly identified organisms include Staphylococcus saprophyticus (5-10% of cases), Proteus mirabilis (more common in males), and Klebsiella species. Streptococci rarely cause uncomplicated UTI; candida species can cause UTI, usually associated with indwelling catheters, immunosuppression or contamination from genital tract.^5,6

Risk factors

Risk factors for recurrent UTI in young and pre-menopausal women include:

• Sexual intercourse
• Past medical history of UTI in childhood
• Having a mother with history of UTI

In post-menopausal and elderly women, risk factors include:

• History of UTI before menopause
• Urinary incontinence
• Atrophic vaginitis
• Cystocele
• Increase post-void urine volume
• Urine catheretisation and reduced functional status in elderly institutionalised women.

INCIDENCE AND PREVALENCE

UTI is one of the most common conditions presenting in primary care.

Acute UTI occurs in up to 50% of women and estimates suggest that by age 24, nearly one third of females will have had at least one episode of cystitis. 20-30% of women who have had a UTI will have a recurrence. An observational study of around 1 million people aged ≥65 years found that 21% had at least one clinically diagnosed UTI over the 10-yaear period. Incidence increased from 9-11% in women aged 65-74 years, 11-14% in those aged 75-84 years, and 15-20% in those aged over 85 years.⁷

Catheter associated UTI (CA-UTI)

Bacteriuria develops within days of catheterisation and over time, everyone with a catheter will have bacteriuria.

Asymptomatic bacteriuria

Asymptomatic bacteriuria is estimated to occur in:

• 2-10% of pregnant women
• 1-5% of healthy pre-menopausal women
• 4-19% of healthy elderly women, increasing to up to 50% in women in long-term care
• 0.7-27% of people with diabetes
• 23-89% of people with spinal cord injuries.

COMPLICATIONS

The main complication of lower UTI is ascending infection which can lead to pyelonephritis, renal and peri-renal abscess, renal function impairment, renal failure, and urosepsis.

UTI in pregnancy is associated with pre-term delivery and low birthweight

An estimated 75% of people with pyelonephritis will have had a previous UTI.

Sepsis is a less common complication of UTI. Bacteraemia occurs infrequently with UTI, but instrumentation of the urinary tract or the presence of indwelling urinary catheters increases the risk.

Risk factors for complicated UTI include:

• Pregnancy
• Older age
• Healthcare associated UTI
• Presence of symptoms for more than a week before presentation
• Urologic instrumentation, including urinary catheterisation
• Pre-existing urological conditions such as childhood or recurrent UTI, neurogenic bladder, polycystic kidney disease, renal transplant, urolithiasis, or urinary obstruction
• Comorbidities such as diabetes and immunosuppression.

PROGNOSIS

Acute, uncomplicated UTI usually resolves within a few days. In women with mild to moderately severe symptoms, UTI resolves after an average of 3.32 days when treated with antibiotic to which the pathogen is sensitive, and close to 5 days when not treated with an antibiotic.

Approximately 25-35% of women with UTI have a recurrent infection within 3 – 6 months and about 44% within 12 months.

DIAGNOSIS

You should suspect UTI in anyone presenting with the following typical features:

• Dysuria – discomfort, pain, burning, tingling or stinging associated with urination
• Frequency – passing urine more often than usual
• Urgency – a strong desire to empty the bladder, which may lead to urinary incontinence
• Changes in urine appearance or consistency, colour or odour or frank haematuria
• Nocturia — passing urine more often than usual at night
• Suprapubic discomfort and/or tenderness.

Typical features may be absent, in particular in elderly people with underlying cognitive impairment. Consider UTI if the person presents with generalised non-specific clinical features such as delirium, lethargy, reduced ability to carry out activities of daily living or poor appetite.

Also consider alternative sources of infection and causes of delirium other than UTI, such as chest infections, which must be excluded before a working diagnosis of UTI is made.

Pyelonephritis should be suspected in people with fever, loin pain or rigors.

Making an assessment

Practice nurses are ideally placed to make an assessment of possible UTI. This assessment should involve a full clinical assessment, history and examination. The important features of this assessment are as follows:

• Symptoms such as vaginal or urethral discharge, irritation or skin rash, which may indicate a cause other than UTI.
• Red flags such as haematuria, loin pain, rigors, nausea, vomiting, and altered mental state — consider the possibility of serious illness such as sepsis.
• Family history of urinary tract disease such as polycystic kidney disease.
• Possibly of pregnancy in women of childbearing age — carry out a pregnancy test if unsure.
• Past medical history including risk factors for recurrent UTI such as neurological conditions, diabetes mellitus, immunosuppression, urolithiasis, and bladder catheterisation.
• Medication, including recent antibiotics.

Examination

Check vital signs (temperature, blood pressure, heart rate and respiratory rate), looking for signs of systemic illness or sepsis.

Palpate for flank or suprapubic tenderness and pelvic or abdominal masses.

Consider other diagnoses (for example pyelonephritis, obstruction or malignancy) if the person has significant abdominal pain, flank tenderness or a pelvic or abdominal mass.

Check for blockage if there is a urinary catheter in situ.

Assess other systems depending on suspected cause, for example, genital examination if vulvovaginal atrophy or herpes simplex is a possibility.

Check for all new signs and symptoms of UTI — new onset dysuria alone, or two or more of:

• Temperature 1.5°C above normal twice in the last 12 hours
• New frequency or urgency
• New incontinence
• New or worsening delirium/debility
• New suprapubic pain
• Visible haematuria.

Check for two or more localised signs and symptoms of other infection (respiratory tract, gastrointestinal tract, skin and soft tissue).

Investigations in women with possible UTI

If the woman is under 65 years of age, and does not have risk factors for complicated UTI, urine dipstick can be used as an aid to diagnosis. Dipstick is an unreliable method of assessment in women aged older than 65 years and those who are catheterised.⁸

There are three possible results of dipstick testing

1. If dipstick is positive for nitrite or leukocytes and red blood cells (RBC) then a UTI is likely.

In this case, a urine sample (morning sample most reliable) for culture and sensitivities should be sent if previous antibiotic treatment has failed or there is a possibility of antibiotic resistance. Sample containers with boric acid preservative should be filled to the marked line.

2. If urine dipstick is negative for nitrite and positive for leukocyte, UTI is equally likely to other diagnosis. In this case you should send urine for culture to confirm the diagnosis.

3. If urine dipstick is negative for all nitrite, leukocyte and RBC, UTI is less likely. In this case there is no need to send sample for urine culture, instead you should consider other diagnoses.

A sample should be sent for urine culture in all women with suspected lower UTI who:

• Are pregnant
• Are older than 65 years
• Have symptoms that are persistent or do not resolve with antibiotic treatment
• Have recurrent UTI (two episodes in 6 months or three in 12 months)
• Have a urinary catheter in situ or have recently been catheterised
• If the catheter has been changed the sample should be collected from the newly placed catheter — using aseptic technique drain a few mL of residual urine from the tubing, then collect a fresh sample from catheter sampling port
• Ensure the microbiology request form states that this is a suspected catheter-associated infection and details of any antibiotic prescribed
• Have risk factors for resistance or complicated UTI such as abnormalities of genitourinary tract, renal impairment, residence in a long-term care facility, hospitalisation for more than 7 days in the last 6 months, recent travel to a country with increased resistance or previous resistant UTI
• Have atypical symptoms
• Have visible or non-visible (on urine dipstick) haematuria.

DIFFERENTIAL DIAGNOSIS

If urinary symptoms with fever and/or loin pain, suspect pyelonephritis.

If there are urinary symptoms but no evidence of UTI on urine culture, consider conditions which can present in a similar way to UTI, such as:

• Other urological or genitourinary conditions e.g. atrophic vaginitis, lichen sclerosis, lichen planus, urolithiasis, or interstitial cystitis
• Dermatological conditions such as psoriasis, irritant or contact dermatitis
• Spondyloarthropathies such as reactive arthritis or Bechet’s syndrome
• Malignancy

Gynaecological malignancy (e.g. ovarian cancer) may present with persistent or frequent increased urinary urgency and/or frequency

Urological malignancy may present with haematuria (visible or non-visible).

• Trauma due to genitourinary procedures, sexual intercourse, sexual abuse or physical activity such as cycling
• Adverse drug effects – some drugs such as cyclophosphamide, opioids, and nifedipine can cause urinary tract symptoms.

Conclusion

Urinary tract infection is a common presentation in primary care. Most patients will present with uncomplicated infections and classic symptoms. However, practice nurses are uniquely placed to deal with atypical presentations and the full range of complexity of patients, male and female, young and old, pregnant and those at high risk of complications.

References

1. Butler C, Hawking M, Quigley A, McNulty C. Incidence, severity, help seeking, and management of uncomplicated urinary tract infection: a population-based survey. Br J Gen Pract 2015;65(639):e702-707

2. Little P, Moore M, Turner S, et al. Effectiveness of five different approaches in the management of urinary tract infection: randomised controlled trial. BMJ 2010;340:c199

3. Butler C, Francis N, Thomas-Jones E, et al. Variations in presentation, management, and patient outcomes of urinary tract infection: a prospective four-country primary care observational cohort study. Br J Gen Pract 2017;67(665):e830-e841

4. NICE Clinical Knowledge Summaries. Urinary Traction Infection https://cks.nice.org.uk/

5. Dason S, Dason JT, Kapoor A. (2011) Guidelines for the diagnosis and management of recurrent urinary tract infection in women. Canadian Urological Association Journal 2011;5(5):316-322.

6. EAU. Urological infections. European Association of Urology; 2018 https://uroweb.org/

7. Lee U. (2018) Urinary tract infections in women. BMJ Best Practice 2018. https://bestpractice.bmj.com/topics/en-gb/77

8. Public Health England. Diagnosis of urinary tract infections: quick reference tool for primary care; 2018. https://www.gov.uk/government/publications/urinary-tract-infection-diagnosis