Urinary Tract Infections in Spinal Cord Injury 

Updated: Apr 15, 2016
  • Author: John L Brusch, MD, FACP; Chief Editor: Michael Stuart Bronze, MD  more...
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Epidemiology and Pathophysiology

There is a heightened risk of urinary tract infection (UTI) in patients with a spinal cord injury (SCI). Lower rates occur in those with incomplete injuries. The overall incidence of urinary tract infection in SCI is 2.5 cases per year. [1] In patients practicing clean intermittent catheterization, the mean incidence of UTIs is 10.3 cases per 1000 catheter days; after 3 months, the rate is fewer than 2 cases per 1000 catheter days. Once a urethral catheter is in place, the daily incidence of bacteriuria is 3-10%. Because most patients become bacteriuric by 30 days, that is a convenient dividing line between short- and long-term catheterization.

UTIs in patients with SCI develop as a result of neurogenic bladder and the need for catheterization. Pathogenetic factors include bladder overdistention, vesicoureteral reflux, high-pressure voiding, large postvoiding residual volume, stones in the urinary tract, and outlet obstruction. [2]

Patients with SCI develop UTIs with microorganisms that form dense biofilms on the bladder wall; thus, these infections are difficult to eradicate. Organisms that commonly cause infections include Proteus, Pseudomonas, Klebsiella, Serratia, and Providencia species, along with enterococci and staphylococci. Approximately 70% of infections are polymicrobial.

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Clinical Presentation

In patients with spinal cord injury, signs and symptoms suggestive of a urinary tract infection are malodorous and cloudy urine, muscular spasticity, fatigue, fevers, chills, and autonomic instability.

Patients with lesions above T6 may exhibit autonomic dysreflexia to noxious stimuli, such as an overdistended bladder. The sympathetic response below the level of injury is uninhibited, producing severe vasoconstriction and reflexive bradycardia. If the patient is febrile, this may appear as a pulse-temperature dissociation.

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Diagnostic Testing

Urinary tract infection (UTI) patient's with spinal cord injury SCI is challenging to diagnose because all of these individuals have some degree of bacteruria but not all are actively infected. Treatment should be reserved for symptomatic patients (see Clinical Presentation). [3]

Patients with SCIs who have more than 2 symptomatic UTIs within 6 months should be evaluated to rule out high-pressure voiding, vesicoureteral reflux, and the presence of stones. Evaluations often include some combination of the following:

  • Urodynamic studies
  • Nuclear scanning
  • Renal ultrasonography [4]
  • Voiding cystourethrography
  • Abdominal computed tomography (CT)
  • Intravenous pyelography (IVP)
  • Cystoscopy
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Treatment & Management

Antibiotics should be reserved for spinal cord injury (SCI) patients who have clear signs and symptoms of urinary tract infection (UTI). [3, 5, 6]

The empiric choice of antibiotics in SCI needs to be individualized for the characteristics of the specific patient, such as past history of urinary tract infections, possibility of extended-spectrum beta-lactamase–forming organisms, the presence of leukopenia or other immunosuppression, and/or presence of sepsis. The patient should be treated for 2 weeks in the setting of pyelonephritis.

If a patient fails to respond, then another urine culture should be obtained and an imaging study should be considered to rule out persistent infection, stone disease, and anatomic abnormalities causing obstruction.

Because of the inevitable development of multidrug resistance, long-term antibiotic prophylaxis is seldom justified. [7]

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Preventive Measures

For patients with spinal cord injury (SCI), the efficacy of short-term prophylaxis with trimethoprim-sulfamethoxazole or nitrofurantoin has been demonstrated. The possibility that microbial resistance will develop is a major concern, especially in an institutional setting.Risk can be decreased by the use of intermittent catheterization. The guidelines on catheter-associated urinary tract infection (UTI) developed by the Centers for Disease Control and Prevention (CDC) in 2009 state that catheter use and duration should be minimized in all patients, especially those at higher risk for catheter-associated UTI (eg, women, elderly persons, and patients with impaired immunity). [8, 9] According to the guidelines developed by the Infectious Diseases Society of America (IDSA) in 2009, strategies to reduce the use of catheterization are proved to be effective and may have more impact on the incidence of catheter-associated UTI and asymptomatic bacteriuria than other approaches addressed in the guidelines. [10]

See Urethral Catheterization in Women.

Reflex bladder pressures higher than 50 cm H2 O should be avoided through the use of alpha-blockers, anticholinergics, transurethral sphincterotomy, or electrical stimulation.

Using a 6% bleach solution to clean reusable leg bags and seat covers reduces the rates of infection and asymptomatic bacteriuria.

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