Chapter 27 Recurrent urinary tract infection
AETIOLOGY AND EPIDEMIOLOGY
A urinary tract infection (UTI) is by simplest definition an infection that affects any part of the urinary tract, including the kidneys, ureters, bladder and urethra. Most infections will involve the lower tract, which includes the urethra and the bladder. UTIs are most commonly caused by the organism Escherichia coli.1 Infections typically develop when bacteria or viruses enter the urinary system through the urethra. Once inside the bladder, the bacteria begin multiplying until their numbers are large enough to cause infectious symptoms (usually more than 100,000 organisms per mL in a midstream urine sample). Infections may cause swelling of the urethra (urethritis), bladder (cystitis), epididymis (epididymitis) or one or both testicles (orchitis).1 Females are far more likely to present with UTIs than males, as the female urethra is closer to the anus (and its bacterial load) than the male urethra. Most UTIs are classified as ‘uncomplicated’, being caused by a transient infection of a single strain of proliferative bacteria.2 Other cases, however, are classed as ‘complicated’ and are caused by urinary tract dysfunction or disease, or via an overarching medical condition such as diabetes. In the latter case concern exists in regard to potential renal damage; medical referral is advised.
Common symptoms associated with UTI include urgency to urinate, a burning sensation during micturition, haematuria, cloudy or foul (or otherwise abnormal) smelling urine, and frequently passing small amounts of urine.1,3 Symptoms suggestive of urethritis include a burning sensation during micturition and, in men, penile discharge. Symptoms suggestive of cystitis may include pelvic pressure, lower abdominal pain and painful and frequent urination.1,3 Symptoms suggestive of epididymitis in men include scrotal pain; tenderness in the testes and groin; painful intercourse, ejaculation and urination; and orchitis.1,3
Screening of asymptomatic women has shown that approximately 5% will have some form of UTI, 11% of women will experience UTI in any given year and 50% of women will experience symptoms of cystitis at some stage in their life.4,5 All males who present with a UTI should be referred for investigation to exclude any underlying abnormality such as prostatitis. The differential diagnoses of vaginitis or vulvovaginal infections (such as Candida spp.) are also often associated with vaginal discharge.1
RISK FACTORS
Sexual intercourse frequency is the strongest risk factor for UTIs in younger populations.1 Exposure to spermicide and new sexual partners are additive risk factors.6 Diabetes is also a risk factor for UTIs, particularly for complicated UTIs, and women who require medical management for this condition will run roughly twice the risk of developing a UTI than non-diabetic women.7 Low levels of oestrogen can dramatically change the microflora from one dominated by Lactobacillus to one dominated by E. coli, therefore increasing the risk of UTI (it should be noted that this may be of clinical relevance only in postmenopausal women).8
CONVENTIONAL TREATMENT
Conventional treatment of UTIs relies on antibiotic therapy, and in most cases of uncomplicated infection can be managed easily, with antibiotic treatment expected to cure 80–90% of uncomplicated UTIs.5 Optimal treatment also includes adjuvant recommendations such as increasing fluid intake, encouraging complete bladder emptying and urinary alkalinisation for severe dysuria.5 Simple analgesics such as paracetamol are recommended for pain. Recurrent UTIs are usually defined as three or more UTIs in a 12-month period, and in these women a larger focus on preventive treatment is advised, even as far as prophylactic antibiotic use after sexual intercourse.5
KEY TREATMENT PROTOCOLS
The primary naturopathic treatment goals for UTIs are to initially combat the urinary pathogen and ameliorate symptoms such as pain and fever. Long-term treatment protocols are to enhance the patient’s immune function to appropriately remove and resist infection, remove possible irritants, restore urinary tract microflora, prevent bacteria from adhering to the mucosal wall of the bladder, and promote preventive behaviours. Herbal medicine has a strong tradition of use in genitourinary conditions (see Table 27.1), although many herbal medicines’ mechanisms of action and clinical efficacy have yet to be validated.
Antimicrobial activity
Encouraging healthy bacterial balance may be achieved by preventing dysbiosis and promoting healthy gastrointestinal bacteria populations. As most infections are the result of E. coli from the digestive tract, promoting a diet that favours healthy microflora ratios may be beneficial in reducing the incidence of UTI. A Finnish study, for example, found that women who consumed fermented dairy products containing probiotic strains had a reduced risk of developing UTI.11 The consumption of fresh juices, particularly berry juices, was also associated with decreased risk of developing UTI. Clinical investigation of women who are predisposed to recurrent UTI has also uncovered reduced beneficial microflora populations even during times of non-infection.12,13
Although it is known that pathogenic urogenital flora proliferate at the time of infection, attempts to restore balance with probiotic supplements to reduce UTI show mixed results.14 Specific strains of probiotics can be beneficial for preventing recurrent UTIs in women and generally have a good safety profile. Lactobacillus rhamnosus and L. reuteri either intravaginally or orally are most effective, while L. casei shirota and L. crispatus showed efficacy in some studies; L. rhamnosus does not seem as effective.15,16 Controversy still surrounds the use of probiotics for UTI prophylaxis due to limited and mixed evidence. As with all instances in using specific probiotic strains for specific therapeutic effects, care needs to be taken to identify the appropriate strain (see Chapter 3 on irritable bowel syndrome for more discussion on suitable probiotic strains for specific conditions).
The isoquinoline alkaloid berberine from Hydrastis canadensis, Coptis chinensis and Berberis vulgaris has a strong effect in treating UTIs due to bacteriostatic activity.17 Its effects have been confirmed against a number of bacteria including Staphylococcus spp., E. coli and Streptococcus spp.18 Arctostaphylos uva-ursi, rich in the phenolic constituent arbutin, also provides strong antimicrobial activity and has preliminary clinical evidence.19 Clinical studies using these botanicals are now required to confirm this activity in humans.
Inhibition of bacteria adhering to bladder wall
A key protocol in treating UTIs is to reduce bacterial proliferation in the bladder and their adherence to the bladder wall. In addition to increasing diuresis and providing an antimicrobial and bacteriostatic action, interventions that interfere with bacterial adherence will be of benefit. A key lifestyle measure in reducing bacterial colonisation and adherence on bladder tissue is complete urination after sexual intercourse. The main phytotherapy studied for this action is Vaccinium macrocarpon (cranberry), and its cousins blueberry and bilberry. In vitro and animal studies have demonstrated that cranberry consumption inhibits the binding of bacterial strains such as E. coli to uroepithelial cells.17,19 It appears that the anthocyanidins are responsible for this activity. A Cochrane review and meta-analysis revealed that cranberry or cranberry and lingonberry significantly reduced people’s chances of developing UTIs over a 12-month period.20 It was concluded that cranberry juice or tablets may preferentially benefit women with chronic recurring UTIs compared with elderly men or people with bladder infections due to catheterisation.
A botanical with traditional use in UTIs is Juniperus spp. This medicinal plant may provide an anti-UTI effect via bacteriostatic, diuretic and anti-adhesion effects, but to date no human clinical trials substantiate this.19 It should be noted that a common misconception exists about Juniperus spp. and nephrotoxicity. Close evaluation of the literature reveals that a review of the evidence does not support this effect, and that previous case studies may be based on adulteration of the juniper oil.19 As mentioned previously, the isoquinoline alkaloid berberine has a potential effect in treating UTIs due to bacteriostatic action; this constituent also has demonstrated anti-adhesion activity against a number of bacteria including Staphylococcus spp., E. coli and Streptococcus spp.18,17 The nutrient D-mannose may also provide anti-adhesion activity against bacteria such as E. coli. This simple sugar has been shown to bind to uroepithelial cells to which bacteria normally adhere, thereby interfering with colonisation.17 While a promising intervention it should noted that current evidence is based on in vitro and animal studies.
Enhancement of diuresis
The most obvious way to increase diuresis is by use of aquaretics: agents that increase water excretion via effects on glomerular filtration as opposed to affecting electrolyte control with diuretics.19 Water and herbal teas related to treatment are the preferable methods of increasing liquid intake. Although most botanicals used for this effect are regarded as being aquaretic, there have been some studies on the diuretic effects of certain herbs that are noted to be potentially beneficial in conditions like oedema and hypertension.19 Reference is particularly made in this instance to the herb Taraxacum officinale where the leaf especially has demonstrated diuretic affects due in part to potassium content.21 An added benefit for use of T. officinale in diuresis is that potassium levels are compensated for the loss of this mineral in urine output.22 The first human study to evaluate the diuretic effects of this herb showed promise for its use as a diuretic.23 The pilot study used fresh leaf hydroethanolic extract of T. officinale (8 mL t.d.s.) in 17 participants to investigate whether an increased urinary frequency and volume would result (compared to prerecorded baseline measurements). Results revealed a significant increase in the frequency of urination in the 5-hour period after the first dose. There was also a significant increase in the excretion ratio in the 5-hour period after the second dose of extract. The third dose, however, failed to significantly alter any of the measured parameters. For more detail on the use of T. officinale as a diuretic, refer to Chapter 10 on hypertension.
