Urinary Tract Infections in Spinal Cord Injury

The rate risk of urinary tract infection (UTI) in patients with a spinal cord injury (SCI) is proportionate to the extent of both neurologic and urologic damage.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 has decreased to fewer than 2 cases per 1000 catheter days. Once a urethral catheter is in place, the daily incidence of bacteriuria is 3% to 10%. Because most patients become bacteriuric by 30 days, this number serves as a convenient dividing line between short- and long-term. Pathogenetic factors include bladder overdistention, vesicoureteral reflux, high-pressure voiding, large postvoiding residual volume, stones in the urinary tract, and outlet obstruction. ^[2]

Patients typically develop UTIs with organisms that form biofilms on the bladder wall. A biofilm represents a community in which cells adhere to one another and usually to a variety of body surfaces. ^[3]  Such infections are difficult to eradicate. Causative pathogens include Proteus, Pseudomonas, Klebsiella, Serratia, and Providencia species, along with enterococci, candida species, and staphylococci. Approximately 70% of infections are polymicrobial.

The marked increase in use of anticrobial agents during COVID-19 has promoted the proliferation of resistant bacterial and fungal infections. ^[4]  C auris ^[5]  is a newly recognized fungus with unique properties that enable it to spread rapidly through a healthcare institution and pass widespread resistance to the usual antifungals.

There is a significant correlation between UTI in patients undergoing rehabilitation for traumatic SCI and decreased gains in functional independence measures. ^[6]

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.

Please see Urinary Tract Infection (UTI) and Cystitis (Bladder Infection) in Females.

Urinary tract infection (UTI) in patients 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). ^[7]

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 ^[8]

• Voiding cystourethrography

• Abdominal computed tomography (CT)

• Intravenous pyelography (IVP)

• Cystoscopy

Antibiotics should be reserved for patients with spinal cord injury (SCI) who have clear signs and symptoms of urinary tract infection (UTI). ^{[7, 9, 10]}

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

If a patient fails to respond, a repeat 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 seldom is justified. ^[11]

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. The 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). ^{[12, 13]} 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. ^[14]

The role of prophylactic antibiotics is quite minimal. Too often, the importance of maintaining renal function in these patients is overlooked. Such can be acheived by increasing bladder capacity, decreasing bladder pressure, or promoting detrusor contractility. Urinary diversion also may be considered. ^[15] In summary, high quality care of these patients requires a team approach of medical physicians, physiatrists, urologists, and ID specialists. 

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.

Currently, no evidenced-based measures for prophylaxis of UTI in patients with neurogenic bladder exist. However, the most promising unproven methods include the use of bacteriophages and probiotics. ^[16]

It is important to pay attention to the non-UTI complications of SCI pressure sores, pulmonary infections, and venous thromboembolism. ^[17]