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14. Urinary Tract Infections of the Neurogenic Bladder
High risk patient group for recurrent UTIs.
Neurogenic lower urinary tract dysfunction increases the risk of UTIs due to a variety of factors including voiding dysfunction, catheters, stones, obstruction and bowel dysfunction.
Classic symptoms of dysuria, frequency and urgency maybe absent in patients with neurogenic bladders due to the insensate nature of their body/urinary tract from their underlying neurological disorder.
UTIs in neurogenic bladder patients are always deemed complicated UTIs therefore antibiotic treatment and duration should reflect this accordingly.
•Non-antibiotic prophylaxis management options are similar to patients without neurogenic bladders.
Patients with neurogenic lower urinary tract dysfunction (NLUTD) are at increased risk of recurrent urinary tract infection (UTI), with much higher incidence reported compared with a “normal” population. As a result, this leads to increased utilisation of healthcare resources as well as morbidity and even mortality in some cases. As expected, the underlying cause, as well as the investigation and management of UTIs in this unique population is different to patients with a “normal” bladder and will be explored further by this chapter.
14.1 Pathophysiology
NLUTD has multiple causes which can be classified into;
Congenital—Bladder dysfunction is frequently seen in patients with spina bifida, with vesico-ureteral reflux present in up to 40% of children affected by 5 years of age and with up to 60.9% of young adults with spina bifida experiencing urinary incontinence [1, 2]. The spastic cerebral palsy population has an estimated 36% prevalence of NLUTD [3].
Acquired—traumatic injuries, such as spinal cord injury (SCI) or neurological conditions. In the United States, up to 40–90% of patients with multiple sclerosis, 37–72% of patients with Parkinson’s disease, and 15% of patients with stroke have NLUTD [1, 4]. Less common causes of NLUTD may include diabetes mellitus with autonomic neuropathy, unintended sequelae following pelvic surgery, and cauda equina syndrome resulting from lumbar spine pathology [1].
The subsequent disruption of the micturition cycle give rise to LUT dysfunction. UTIs in NLUTD occurs either due to the LUTD (e.g. incomplete bladder emptying, stone formation) or because of treatment (e.g. intermittent/long term catheterisation).
14.1.1 Precipitating Factors
14.1.1.1 Voiding
Incomplete emptying of the bladder leading to stagnation of urine is a well-known risk for UTI, with as little as 20 ml of stagnant urine found to be linked to recurrent UTI [5–7]. Kim et al. reported that a post-void residual urine volume of more than 100 ml led to an increase chance of acquiring UTI by 4.87 times in stroke patients undergoing rehabilitation [8].
14.1.1.2 Catheters
There are data demonstrating that the bladder drainage method is the most important predictor of symptomatic UTIs, with indwelling catheters being the highest risk [9]. If patients are unable perform Clean intermittent self-catheterisation (CISC) alternative options include sphincterotomy in male patients (with a subsequent Convene sheath), ileovesicostomy and ileal loop urinary diversion.
14.1.1.3 Stones
Stones represent a nidus for persistent infection, either obstructing or non-obstructing. A retrospective study of patients with non-obstructing asymptomatic renal calculi and recurrent UTIs who underwent surgical removal, showed nearly 50% of the patients remained infection-free after the stone removal [10].
14.1.1.4 Obstruction
May occur as a result of Detrusor Sphincter Dyssenergia (involuntary contraction of the external sphincter and detrusor muscle simultaneously). Patients, who have undergone urinary diversion require monitoring with annual renal ultrasound. Obstruction can occur at the level of the stoma (treated by gentle digitalisation, catheterisation for draining residual urine), or at the ureteroileal anastomosis level (which can be treated with revision surgery or ureteric stents). Loopogram studies looking for reflux is the best mean for evaluation of a urinary conduit.
14.1.1.5 Bowel Dysfunction
Is thought to cause UTI by perineal contamination and trans-colonic migration of bacteria. Intervention to address constipation or incontinence should be encouraged as part of the treatment plan for the UTI’s [11].
14.2 Definition of UTI in NLUT
Fever (Highest specificity 99%, but 6.9% sensitivity)
New onset or increase in incontinence, including leaking around catheter
Increased spasticity
Malaise, lethargy or sense of unease
Cloudy malodourous urine
Pyuria/Leukocyturia (Highest sensitivity 82.8%)
Discomfort or pain over the kidney (costovertebral angle) or bladder or during micturition (dysuria)
Autonomic dysreflexia (A medical emergency for SCI patients above T6 level, triggered by stimulation below the level of injury, mainly the genitourinary tract, causing abrupt sympathetic activity and leading to convulsion, cerebrovascular accidents and death if left untreated)
This is accompanied by laboratory findings of a UTI in urine analysis. It is important to note that often the classic symptoms of dysuria, frequency and urgency are absent due to the insensate nature of their urinary tract from their underlying disease.
14.2.1 Urine Analysis
Whilst setting their criteria for definition of the UTI the International SCI-UTI Basic Data Set used a study performed on SCI patients, which showed that combined nitrites and leucocyte esterase have a sensitivity and specificity of 0.79 and 0.99, respectively when compared with urine culture [13]. It is of note that when the National Institute on Disability and Rehabilitation Research (NIDDR) criteria was implemented [14], higher rates of overtreatment and lower rates of undertreatment were found when following the urine dipstick test as compared to positive bacteriuria [15]. One explanation is the inability of Enterococcus among other bacteria to reduce nitrates to nitrites. Hence, if there is an intention to treat an episode of UTI in SCI individuals, urine dipstick for nitrites and leucocyte esterase may be an initial indication, but should be followed by urine culture and sensitivity.
14.2.2 Positive Urine Culture
Urine for culture should ideally be collected as a clean catch midstream technique, which in NLUTD patients may be the urine from the insertion of a new urethral/suprapubic catheter. A growth of 103 CFU/mL is a reliable finding with standardised inoculation with 10 μL urine [16]. Having more than 2 species is not considered contamination, provided that the collection technique was sterile.
14.3 Clinical Evaluation of Neurogenic Bladder
- 1.
Clinical history
- (a)
History of the injury—Good history taking enables recognition of the level of injury, which allows for prediction of urological dysfunction.
- (b)
Urological history—LUTS, urological symptoms including previous surgeries and red flag symptoms such as haematuria, that warrant further investigations.
- (c)
Drug history
- (a)
- 2.
Bowels, erections, mobility, dexterity, cognition and comorbidity, family/social support and medical care that may influence bladder management need to be evaluated
14.3.1 Clinical Examination and Investigations
- 1.
Neurological examination—Including mental status, strength, sensation, and reflexes
- 2.
Rectal examination—anal tone, faecal impaction
- 3.
3-day bladder diary—records type and volume of fluid intake, incontinence episodes, number of pads used and a recorded chart of urinary frequency and voided urine volume (i.e. functional bladder capacity). Will also detect concomitant conditions such as nocturnal polyuria
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