15 Urinary problems

Urinary Tract Infection (UTI)

How common are UTIs?

A total of 10–15% of healthy non-pregnant women will suffer from acute uncomplicated cystitis each year ¹ with the highest incidence (17.5%) reported by women aged 18 to 24 years. By age 24, one-third of women will have at least one physician-diagnosed UTI that was treated with prescription medication.¹ Some 12% of women with an initial infection and 48% of those with recurrent infections will have a further episode in the same year.²

What are the classic symptoms and signs?

Classically, women present with urinary frequency, urgency and dysuria. Dysuria without vaginal discharge or irritation has a positive predictive value of 77% for a positive urine culture.³ Affected patients may complain of pelvic discomfort pre- and post-voiding, passing small quantities of urine and sometimes of haematuria. Some may have suprapubic tenderness or pain.

In the majority of cases, infection is limited to the lower urinary tract (i.e. the bladder and urethra: cystitis) but infection can also affect the upper urinary tract causing pyelonephritis. In uncomplicated cystitis, it is rare for women to present with fever or constitutional symptoms. Pyelonephritis is more likely to be associated with back pain, fever, nausea and vomiting.

In uncomplicated cystitis, it is rare for women to present with fever or constitutional symptoms.

Is there anything else that it could be?

In about 50% of women who present with urinary symptoms, there is no bacteriuria. These women nevertheless present with dysuria, frequency and urgency.⁴ Pyuria may be present or absent. They are said to have acute urethral syndrome, or interstitial cystitis or irritable bladder.

The aetiology of urethral syndrome is unclear, but it may be due to bacteria found in low concentrations or bacteria that are difficult to culture, or to nonspecific inflammation or muscular dysfunction.

Other causes of dysuria and frequency include:

• the presence of fastidious organisms such as Ureaplasma urealyticum

• genital pathogens (such as Chlamydia trachomatis, Neisseria gonorrhoeae, herpes simplex virus)

CASE STUDY: Fifth UTI in 6 months

Janey was 25 and presented to her GP with the classic symptoms of frequency and dysuria of 3 days’ duration. She had no fever but had noticed some haematuria that morning. She had a previous history of several urinary tract infections (UTIs) and had been told by another GP about the relationship between UTIs in young women and sexual activity. She tried to remember to void postcoitally and to drink lots of fluid, but this was the fourth or fifth UTI she had had in the last 6 months and she was getting sick of it. After obtaining a urine microscopy and culture (M&C) and making sure that the antibiotics Janey was prescribed were sensitive to the organism, the GP discussed with Janey the use of prophylactic antibiotics. Janey was instructed to complete her course of trimethoprim and then to try using 100 mg of trimethoprim every time she had sex to prevent a further recurrence. A couple of months later Janey returned and reported that she was asymptomatic and not having any further problems.

• vaginal infections with Trichomonas vaginalis and Candida albicans

• infestation with pinworm/threadworm

• irritants (such as deodorants, bubble baths and detergents)

• atrophic urethritis (in postmenopausal women).

How can I explain in simple terms to women how UTIs come about?

Most UTIs occur via an ascending route. This means that bacteria that live around the urethral opening can enter the urethra and climb up, reaching the bladder and establishing an infection.

Are there any factors that predispose to UTIs?

When providing patient education about UTIs, there are a number of predisposing factors ^1,^5,^6,⁷^–⁹ that should be highlighted, the strongest of which, in young women, is recent sexual activity (the relative odds of acute cystitis increase by a factor of 60 during the 48 hours after sexual intercourse).¹⁰ It is important to inform women of the risk factors, so that they can understand how their own behaviour is related to the onset of UTIs. These factors are listed in Box 15.1. GPs should also be aware of factors that may lead to a more complicated situation, such as abnormalities of urinary tract function (for example, indwelling catheter, neuropathic bladder, vesicoureteric reflux, outflow obstruction, other anatomical abnormalities), previous urinary tract surgery and states of immunocompromise, and neurological disorders. Pregnant women are also at increased risk of pyelonephritis associated with the relative ureteral obstruction during gestation. Risk factors for UTI in postmenopausal women include recurrent UTI, bladder prolapse or cystocele, and increased post-void residual urine.¹¹

The relative odds of acute cystitis increase by a factor of 60 during the 48 hours after sexual intercourse.

In a general practice population, what are the common organisms responsible for UTIs?

Box 15.2 lists the common organisms responsible for UTIs in a general practice population. Approximately 80% are caused by E. coli and 13% by Staphyococcus saprophyticus.¹²

What should a GP do when a woman presents with symptoms of a UTI?

Besides taking a history and checking for fever and the possibility of upper urinary tract infection, GPs need to decide whether to investigate the urine or treat empirically.

A mid-stream specimen of urine can be tested either by a urine dipstick or by sending the sample to a laboratory for microscopy and culture. Urine microscopy and culture has long been the ‘gold standard’ for diagnosis of UTIs but it is expensive and slow to produce a result. Dipstick testing, on the other hand, can be performed on the spot by a GP or nurse. When it shows the presence of either leucocyte esterase or nitrites, it is highly predictive of a positive urine culture (whereas absence of either finding markedly reduces the likelihood of infection),¹³ and it has been found to be a fairly reliable way to diagnose UTIs. It is important, however, to undertake urine culture if an accurate diagnosis is needed or in order to select an effective antimicrobial (as in pregnancy, treatment failure or immunocompromise). Box 15.3 (p 286) outlines the tests commonly carried out by dipstick testing and Table 15.1 (p 286) advises how to use nitrite and leucocyte testing to guide management in symptomatic female general practice patients.

BOX 15.3 Pertinent findings on urine dipstick analysis in cases of UTI

(From Fitzgerald ⁵⁴)

• Leucocyte esterase (LE)

– If positive, indicates presence of neutrophils >white blood cells/high power field.

– As an indicator of UTI, this has a sensitivity of 75–90%.

• Nitrites

– Are a surrogate marker for bacteriuria.

– Presence indicates bacterial reduction of dietary nitrates to nitrites by selected Gram-negative uropathogens, including E. coli and Proteus.

– A negative test does not therefore rule out UTI, because some pathogens do not produce nitrate reductase, and frequent urination (common in cystitis) reduces the time available for the enzyme to act.

– Best done on well-concentrated urine (e.g. first morning void). For nitrites to be present, urine should be held in the bladder for >1 hour in order for nitrate-to-nitrite conversion to take place.

• Protein

– Dipsticks are most sensitive for albumin, commonly present in febrile response or in presence of protein-containing substances such as blood cells, bacteria and mucus.

• pH

– Normally urine is acidic. However, if the pH is found to be alkaline in the presence of UTI symptoms and positive LE, Proteus may be present, splitting urea into CO₂ and ammonia, causing a rise in pH.

TABLE 15.1 How to use dipstick testing in the management of women with symptoms of an uncomplicated UTI

Management based on dipstick testing and empirical use of first-line antibiotics is still appropriate for GP patients with uncomplicated UTI.

Imaging of women with an uncomplicated UTI is not warranted, as there is a low yield of positive results.¹⁴ Neither is a single episode of pyelonephritis associated with a clinically significant risk of anatomic abnormality.¹⁵ However, in cases of recurrent pyelonephritis imaging with renal ultrasound, intravenous pyelogram or voiding cystourethrogram is indicated.

Imaging of women with uncomplicated urinary tract infection is not warranted.

Should all women presenting with a UTI have urine M&C carried out?

Uncomplicated UTI in non-pregnant women rarely causes severe illness or has significant long-term consequences, and in 50% of patients the condition improves without antimicrobials within 3 days.¹⁶ Despite this, empiric treatment of uncomplicated UTIs has been advocated by some as the most cost-effective way to manage UTIs.^17,¹⁸ Those against empiric management argue on two grounds. First, they say that the urine should be examined to ascertain the diagnosis, limit unnecessary use of antibiotics and identify those patients who may require further investigation. Second, they argue that since uncomplicated UTIs account for a substantial proportion of all prescribed antibiotics, empiric management may lead to rising levels of antibiotic resistance in the community. With regard to this latter argument, however, levels of resistance found in the laboratory may overestimate levels of resistance in general practice.¹⁹

In 50% of non-pregnant women with an uncomplicated UTI, the condition improves without antimicrobials within 3 days.

What antibiotic choices are there?

Whether treatment is empiric or not, as with all antibiotic prescribing there are a few general rules to follow ¹⁹:

• Because uncomplicated cystitis is so common, antibiotics that are seldom prescribed for other infections should be preferred.

• Individual doctors should vary their choice of antibiotic from time to time, because increased prescription of one antibiotic may result in higher levels of local resistance.

• Local antibiotic resistance levels should also be considered.

Box 15.4 outlines the preferred antibiotics for the management of uncomplicated cystitis in non-pregnant women.

What is the optimum duration of antibiotic use for women with an uncomplicated UTI?

GPs have a choice of prescribing single-dose, 3- or 5-day, or the more traditional 7- to 14-day therapies for treatment of UTIs. Three-day courses of antibiotics such as trimethoprim are recommended as first-line therapy for lower, uncomplicated UTIs in young women.^20,²¹ One-day treatments are less effective, and longer treatments are associated with increased risk of adverse effects without clinically meaningful improvement in effectiveness.²²

In women over 65, short-course treatment (3–6 days) is probably sufficient for treating uncomplicated UTIs.²³

Is any follow-up required?

If therapy is clinically successful, the only patients requiring a follow-up examination of the urine for bacteria are pregnant women. The reason for this is that it is only in this group of women that treatment of asymptomatic bacteriuria is justified, because of the increased risk of pyelonephritis and preterm delivery.²⁴ Asymptomatic bacteriuria is not related to any increase in morbidity or mortality in other patient groups.

After antibiotic therapy, the only patients requiring a follow-up examination of the urine for bacteria are pregnant women.

What is the risk of recurrence?

Recurrence of dysuria and frequency can either mean failure to eradicate the initial infection or reinfection. Interestingly between 12% and 16% of women receiving empiric therapy for UTI required another course of antibiotics within 4 weeks of their initial symptoms, irrespective of the type or duration of initial antibiotic therapy.²⁵ In these women a longer course of antibiotic should be given rather than using a more sophisticated antibiotic.

What preventive measures or general advice can GPs give to women regarding UTIs?

Adjuvant treatment and preventive measures are frequently recommended in cases of UTI, but few have been rigorously evaluated.

It is not helpful to pursue further diagnostic procedures in women complaining of recurrent uncomplicated cystitis.

What measures can be taken in women suffering from recurrent urinary tract infections?

Case control studies ^6,¹⁰ have found no evidence that poor urinary hygiene predisposes women to recurrent infections, and there is no evidence to support giving women specific instructions regarding the frequency of urination, the timing of voiding (postcoital voiding), wiping patterns, douching, the use of hot tubs or the wearing of pantyhose in order to prevent the occurrence of UTIs.

In postmenopausal women with recurrent UTIs, topical vaginal oestrogen can be effective in reducing recurrence.¹¹

In women who have three or more urinary tract infections a year, a GP has several options for management ²⁷:

1. The woman can self-initiate a short course of antibiotic therapy at the onset of symptoms suggesting cystitis.²⁸

2. If the woman describes a relationship between sexual activity and the onset of symptoms, GPs can recommend that she take 100 mg of trimethoprim after sexual intercourse.²⁹

3. Another option is for the woman to use either 50 mg of trimethoprim or 50 mg of nitrofurantoin daily for 6 months or more if necessary.³⁰

If either of the last two options are put in place, prophylaxis should be started after active infection has been eradicated (confirmed by a negative urine culture at least one to two weeks after treatment is

If women have recurrent UTIs related to sexual activity, GPs can recommend 100 mg of trimethoprim to be taken after sexual intercourse, or the woman can take either 50 mg of trimethoprim or 50 mg of nitrofurantoin daily for 6 months or more.