Prevention of Urinary Tract Infections in Persons with Spinal Cord Injury in Home Health Care

Abstract

More than 250,000 persons in the United States live with spinal cord injury (SCI), and 10,000 to 12,000 new injuries occur each year. Of these spinal cord injured persons, 53% have tetraplegia, 46% have paraplegia, and less than 1% experience complete neurologic recovery. About 48% have complete injuries (i.e., full quadriplegia) and 52% have incomplete injuries (^{Consortium for Spinal Cord Medicine, 2006; National Spinal Cord Injury Statistical Center, 2008}). Almost all persons with neurologic impairment related to SCI have voiding dysfunction. Urinary tract infections (UTIs) have long been problematic for those living with SCI. Once the leading cause of death, urinary complications remain the leading cause of morbidity and the most common infection in persons with SCI (^{Rehabilitation Research and Training Center [RRTC] on Spinal Cord Injury, 2008}). This article provides a brief overview of spinal cord injuries and the effect of SCI on the urinary system. Factors that increase the risk for UTI will also be described.

What Is a Spinal Cord Injury?

Figure

SCI is damage to the spinal cord that results in a loss of function. In general, the higher in the spinal column the injury occurs, the more dysfunction a person will experience. Lesions in the cervical region generally result in paralysis of both upper and lower extremities (tetraplegia or quadriplegia). Injuries below the cervical vertebrae result in paraplegia. There are further distinctions based on whether the injury is complete (i.e., no voluntary movement or sensation below the level of the lesion) or incomplete (i.e., a portion of the cord is damaged leaving some motor function or sensation intact) (^{Nelson et al., 2001}). SCI affects every body system.

Effect of Spinal Cord Injury on the Urinary System

One of the most profound effects of SCI is on the urinary system. The vast majority of those persons with SCI and neurologic impairment also have a voiding dysfunction. Even those with incomplete injuries who are able to ambulate may still have abnormalities in bladder function (^{Consortium for Spinal Cord Medicine, 2006}). Bladder or voiding dysfunction is defined as an abnormality of the filling or emptying of the bladder (^{NYU Urology, 2009}). These voiding dysfunctions may cause upper and lower urinary tract complications (^{Consortium for Spinal Cord Medicine, 2006}). Neurogenic bladder is a term that refers to the origin of the changed bladder function: damage to the nervous system, often caused by a SCI.

A review of normal anatomy and physiology of the urinary system helps identify the changes that occur following SCI. The upper urinary tract consists of the kidneys and ureters. The bladder and urethra compose the lower urinary tract. Problems in the lower tract, such as high bladder pressures, can have a negative effect on the upper tract (^{Consortium for Spinal Cord Medicine, 2006}). The kidneys produce and concentrate the urine and move it into the collecting system where it is propelled by peristaltic waves through the ureters into the bladder. Any ureteral dilation decreases propulsion of the urine, which can delay drainage proximal to that point, resulting in further dilation and possible hydronephrosis. The bladder is divided into the detrusor and the trigone. The detrusor is composed of smooth muscle fibers. Near the neck of the bladder, the muscle fibers form a circular arrangement in three distinct layers that function as a sphincter known as the internal sphincter. This is under the control of the autonomic nervous system. Smooth muscle fibers also extend down the urethra toward the external sphincter. The external sphincter is innervated by sacral nerves, and is under voluntary control in nondisabled persons.

The innervation of the lower urinary tract is complex, as it is a combination of parasympathetic, sympathetic, and somatic nerves. SCI interrupts the usual neurologic control. The kidneys, under involuntary nerve control, continue to filter the urine from the blood and send it through the ureters to the bladder for storage until micturition takes place. The main process of urination affected by SCI is that of emptying the bladder.

The manner in which the bladder works following SCI will depend on the level of injury to the spinal cord. Following a SCI, the bladder will usually be affected in one of two ways: either spastic (reflex) bladder or atonic (flaccid) bladder (^{Lindsey & Klebine, 2008}).

Reflex Bladder

Voluntary control of voiding requires nerve impulses to be sent to and from the brain via the spinal cord. When these pathways are damaged, such as with SCI, voluntary control of the sphincter and contraction of the detrusor muscle of the bladder are absent. Injuries above the level of T12 that damage the spinal cord upper motor neurons but leave the sacral segment intact will result in a reflex bladder. Voiding can occur as the stretch receptors in the bladder wall are triggered from a full or filling bladder, sending impulses via nerves entering the spinal cord near the sacral level. There, these impulses stimulate the motor nerves causing the detrusor to contract. At the same time, other nerve cells in the spinal cord innervate the sphincter muscle to relax. This is called the micturition reflex—the reflex that allows the storage and release of urine. It is an automatic involuntary action, and the person has no control over when the bladder will empty.

With SCI, the action of coordinating the relaxation of the sphincter muscle and contracting the detrusor muscle may be adversely affected, resulting in detrusor–sphincter dyssynergia (DSD). The urethral sphincter muscles may not relax properly when the bladder contracts, causing the flow to be interrupted and the bladder pressure to rise. As the pressures rise, urine may reflux back through the ureters to the kidneys causing hydronephrosis (^{Samson & Cardenas, 2007}). With SCI, in addition to difficulty passing urine, the sense of a full bladder may also be lost because sensory signals from the bladder will not be able to travel to the brain through the damaged spinal cord.

Flaccid bladder

The flaccid bladder occurs when the injury is below the conus medullaris and damages the cauda equina and the micturition reflex is not intact. Nerve impulses from the stretch receptors in the bladder wall do not result in reflex voiding when the bladder is full. This can lead to the bladder being overdistended, and in extreme cases ruptured. If a flaccid bladder is not emptied regularly, and is left to constantly overfill, pressure within the bladder can reach dangerous levels and damage to the kidneys may result from reflux (^{Samson & Cardenas, 2007}).

Bladder Management in the Patient at Home With Spinal Cord Injury

Because of neurologic changes affecting normal urinary function, bladder management to assist emptying will be needed. A bladder management program allows those with SCI to empty their bladder in a way acceptable to them. Three important goals when deciding on a bladder management program are (1) to preserve the function of the upper urinary tract, (2) to minimize lower urinary tract complications such as high pressures, overdistension, and infection, and (3) to be compatible with the person's lifestyle (^{Consortium for Spinal Cord Medicine, 2006}). By following a bladder management program, complications involving the bladder can be reduced, and an increased quality of life achieved by reducing the risk of bladder infections, kidney damage, and bladder accidents.

Because no two spinal cord injuries are alike, there are a number of factors to consider when choosing a bladder management program. Some of those considerations include:

• Type of post-SCI bladder (i.e., reflex or flaccid, DSD)
• Level and completeness of SCI
• Gender of the patient
• Physical barriers (i.e., weight, manual dexterity)
• Availability of family/caregivers and/or home health services to assist in carrying out the method chosen
• Patient's preferences.

Types of Bladder Management

For patients with reflex bladder, it may be possible for the bladder to empty sufficiently just through this reflex mechanism. In this case, male patients can use an external condom-type catheter attached to a drainage bag. There are external urinary pouches for female use (^{Newman, 2008}), although there is little documentation about the efficacy of these in women using a wheelchair.

Several measures are taken to allow better outflow of urine, such as a urethral stent, botulinum toxin injections into the urinary sphincter, or sphincterotomy, a surgical procedure in which small incisions are made in the internal sphincter at the bladder neck (^{Consortium for Spinal Cord Medicine, 2006}). With these methods, there is a risk of UTI related to the stagnation of urine if the bladder does not completely empty. More often, some form of internal catheterization will be needed.

Intermittent Catheterization

Intermittent catheterization (IC) is preferred because it provides a method of emptying the neurogenic bladder without leaving in an indwelling catheter. A straight catheter is inserted into the bladder to drain the urine, and the catheter is removed. This should be done on a regular basis, either based on a timed interval (usually every 4–6 hours) or based on bladder volume to keep the amount of urine less than 500 ml (^{Consortium for Spinal Cord Medicine, 2006}). IC lessens the frequency of complications, such as hydronephrosis, urinary calculi, UTI, and autonomic dysreflexia (Consortium for Spinal Cord Medicine), and most closely simulates normal voiding patterns. The drawbacks are that the person must have good manual dexterity to be able to perform the procedure independently, or must have a caregiver willing and available to do it.

There is a lack of agreement as to performing clean intermittent catheterization (CIC) versus sterile single-use systems. Traditionally, patients have been taught to perform CIC, with directions on how to sanitize and store the catheter for multiple uses. This is acceptable practice according to most sources. However, the Food and Drug Administration considers urinary catheters to be single-use devices. Manufacturers do not recommend cleaning and reuse of products that have not been tested to see how various cleaning products may affect them (^{Smith, 2003}). The Veterans Health Administration, in an informational letter signed by the Under Secretary for Health in December 2007, stated that "VA clinicians should follow the manufacturer's instructions for catheter use. Catheters identified as single-use devices should not be re-used in any setting" (^{Kussman, 2007}). Medicare guidelines have also allowed for adequate number of catheters to use a sterile one for each catheterization (^{Infectious Diseases Society of America, 2008}) up to a maximum of 200 catheters per month (^{Newman, 2008}).

Indwelling Catheters

An indwelling catheter may be required for some patients. There are two main types of indwelling catheters: urethral (foley) catheter and suprapubic catheter. Persons with SCI who require the use of an indwelling catheter typically require them on a long-term or chronic basis.

The most common type of indwelling catheter is the urethral or Foley catheter. The advantage is that it doesn't require the dexterity or caregiver services and time investment of IC. The drawbacks are the increased risk for infection, stone formation, and bladder cancer with long-term use (^{Samson & Cardenas, 2007}). Also, urethral erosion can occur with long-term use of Foley catheter (^{Newman, 2008}).

A suprapubic catheter is a standard Foley catheter that is placed via a small surgical incision through the skin into the bladder just above the pubic bone. The advantages of the suprapubic catheter are that it is easier to change, particularly for female patients. It can be more hygienic, especially if bowel control is a problem, and it provides less interference with intimacy or sexual activity. Drawbacks include the potential for urine leakage via the urethra, and the risks for infection, stone formation, and bladder cancer as seen in urethral Foley use. A study from Long Beach Veterans Administration Hospital Spinal Cord Injury Unit found no significant difference between the two catheter groups, with similar complication rates of UTIs, recurrent bladder or renal calculi, and cancer (^{Katsumi et al., 2009}).

Signs and Symptoms of Urinary Tract Infection in the Spinal Cord Injured Patient

It's common for individuals with SCI to have bacteria in their bladder related to urine stasis or chronic catheterization. This means an increased risk for UTI. Normally urine is sterile. In UTI, bacteria travel to the urethra and then to the bladder, resulting in urethritis and cystitis. A severe infection that is not treated may then travel further up the ureters and infect the kidneys. Most persons with an SCI (80%) have bacteria in the urine that are identified by a urine culture (bacteriuria). This is not considered serious unless it leads to signs or symptoms of infection (^{RRTC on Spinal Cord Injury, 2008}). Asymptomatic bacteriuria represents colonization of the urinary tract without symptoms or signs, and should not be treated with antibiotics. Clinical trials in spinal cord injury patients, and others with indwelling urethral catheters, have consistently found no benefits with treatment of asymptomatic bacteriuria (^{Nicolle, 2006}).

One definition of UTI from the National Institute on Disability and Rehabilitation Research Consensus Statement, "Prevention and Management of Urinary Tract Infection among People with SCI" (1992), as used in the Clinical Practice Guideline for Healthcare Providers (^{Consortium for Spinal Cord Medicine, 2006}), states that three criteria must be met for an individual with SCI to be considered as having a UTI: (1) significant bacteriuria, (2) pyuria (increased white blood cells in the urine), and (3) signs and symptoms. The signs and symptoms of UTI include:

• discomfort or pain over the kidney or bladder (although this may be absent in insensate patients)
• cloudy, dark, and/or malodorous urine
• onset of urinary incontinence or leaking around the catheter
• increased spasticity
• malaise and lethargy
• anorexia
• autonomic dysreflexia
• fever (defined as temperature 2.4° F greater than the patient's baseline temperature [^{Centers for Disease Control and Prevention and the Association for Professionals in Infection Control and Epidemiology, 2008}]) or chills may develop when the infection has reached the upper urinary tract.

Autonomic dysreflexia is a life-threatening condition that occurs in people with an SCI of T6 and above. It occurs as a result of any noxious stimuli, and is marked by a sudden severe elevation in blood pressure, pounding headache, sweating, flushing, goose bumps, chills, feelings of anxiety, and bradycardia (^{Consortium for Spinal Cord Medicine, 2006}). Autonomic dysreflexia can result from a variety of causes, but the most common are urinary problems, such as a full bladder (the need to perform IC, a clogged indwelling catheter) or UTI. For more information on autonomic dysreflexia, readers are referred to http://www.pva.org where a copy of the guideline may be downloaded free of charge.

Prevention of Urinary Tract Infections

Although it is very difficult to prevent all UTIs, a large number could be avoided by good preventive measures. The key is to prevent the spread of bacteria into the urinary system. The prevention strategies described below are applicable to any type of neurogenic bladder dysfunction.

• Hand hygiene remains the first and the most important preventive measure. Patients and caregivers alike should be taught to clean their hands with antibacterial soap or alcohol-based hand cleaners before and after catheter insertion, changing drainage systems, or manipulating the catheter (^{Gould et al., 2009}).
• Proper cleaning of urinary care supplies can help prevent infection. Urinary drainage bags, both bedside drainage bags and leg bags used under clothing when out of bed, should be cleaned daily when they are being used alternately. The best practice for cleansing urinary drainage bags in a hospital setting can be translated for use by clients for self-care within the home setting. Common household bleach diluted in a 1:10 ratio with tap water is a safe and effective method to reduce bacteria when consistently used. Ascending bacteria from the urinary drainage bag may also decrease, resulting in fewer UTIs (^{Nash, 2003}). A commercial cleaning solution marketed for urinary appliances may also be used.
• Urinary drainage bags should be emptied frequently enough to maintain urine flow and prevent reflux, at least when two-thirds full. Bags should always be positioned below the level of the bladder and should not be touching the floor, with the tubing above the level of the collection bag. Care must be taken to prevent kinking of the catheter or the drainage tubing, as this hinders drainage and causes reflux of urine (^{Rhinehart & McGoldrick, 2006}).
• The catheter chosen should be the smallest diameter consistent with good drainage of the bladder to minimize irritation to the urethra and bladder (^{Gould et al., 2009}). A 5 ml balloon should be used and filled according to manufacturer's directions (usually to 10 ml). Larger balloon sizes exert pressure on the bladder neck and may result in bladder spasms and leakage (^{Smith, 2003}).
• Catheters should be secured to minimize trauma to the meatus, urethral erosion, bladder spasms, or dislodging of the catheter (^{Smith, 2003}).
• Daily catheter hygiene should be performed: gentle cleansing of the genital region and proximal catheter with soap and water and thorough rinsing, cleaning from front to back (^{Gould et al., 2009}). In uncircumcised males, the foreskin should be retracted, washed, and dried and then replaced. If leakage of urine or bowel movement occurs, prompt cleansing of the skin and changing of clothing and/or bed linens is important.
• There is some controversy concerning changing indwelling catheters. Some sources recommend catheter changes at a regular frequency varying from every 6 weeks to as often as weekly for patients who tend to form encrustations and stones (^{Consortium for Spinal Cord Medicine, 2006; Willson 2009}), and Medicare guidelines allow for reimbursement for monthly home health visits for catheter change (^{Newman, 2008}). Most sources, however, advocate changing indwelling catheters only when necessary for problems such as obstruction with encrustation or mucus, or leakage of urine (^{Gould et al., 2009; Greene, 2008}). Catheters should be changed in accordance with the patient's plan of care.
• Fluid intake, particularly water, is of prime importance with the use of indwelling catheters. Unless contraindicated because of other medical problems, fluid intake should be 2 to 3 L/day (^{Consortium for Spinal Cord Medicine, 2006}). Drinks containing sugar, caffeine, or alcohol, and carbonated drinks should be used in moderation. Water should be the beverage of choice, as this not only helps to remove bacteria but also lessens the risk of forming urinary stones (^{Lindsey & Klebine, 2008}).

Troubleshooting Catheter Problems

Catheter leakage can occur due to infection, fecal impaction or constipation, luminal occlusion, catheter encrustation, or bladder spasms. Spasms of the bladder create a force that overwhelms the drainage capacity of the catheter, resulting in leakage either around the catheter or via the urethra with suprapubic catheters. Where the likely cause is a blockage, the catheter may be irrigated if ordered by the physician, but if it does not flush easily, the catheter should be changed. If there is encrustation clogging the catheter, and it is forced back into the bladder via irrigation, the risk for a UTI is increased. Acidifying solutions (i.e., Renacidin, Guardian Laboratories, Hauppauge, NY) are sometimes ordered for those who have frequent catheter obstructions, but further research is needed as to the benefit of this treatment (^{Gould et al., 2009}).

If leaking is related to bladder spasms, the cause should be explored and, if possible, eliminated. If indicated, the patient's doctor should be informed for follow-up of the cause of the bladder spasms, or possible use of antispasmodics, such as oxybutynin, to alleviate spasm. Catheter leakage should not be corrected by using a larger diameter catheter because the increased size can further irritate the bladder trigone resulting in an increase in spasms (^{Smith, 2003}).

Nutritional Remedies for Prevention of Urinary Tract Infection

There is some controversy in the literature in regard to use of cranberry to prevent urinary infection (^{Hess et al., 2008; Linsenmeyer et al., 2004; Waites et al., 2004}). The theory that cranberry acidifies the urine, thus inhibiting bacteria replication, has been largely discredited. It is thought that proanthocyanidins unique to cranberry inhibit the ability of bacteria to adhere to the surface membrane of host cells in the urinary tract. Also, cranberry has anti-inflammatory and antioxidant activity (^{National Center for Complementary and Alternative Medicine, 2009}).

Blueberry contains similar constituents as cranberry, and might also prevent bacteria from attaching to the lining of the urinary bladder; however, data and studies are lacking.

Another nutritional supplement that is widely recommended to prevent UTI is Vitamin C, usually 500 mg two to four times daily, although higher doses have been tried. It is thought to increase the acidity level of urine, which, in turn, helps decrease bacteria in the urinary tract system. Earlier studies have not shown significant acidification, but there is currently a proposed study recruiting participants to determine the efficacy of Vitamin C in preventing UTI in persons with SCI (^{Sunnaas Rehabilitation Hospital, 2009}).

There are other nutritional and herbal remedies that some believe may help prevent UTI, such as D-mannose, uva ursi, marshmallow root, goldenseal, and many others. There is a lack of research to verify the effectiveness of any of these.

Medications

Methenamine hippurate or methenamine mandelate are urinary antiseptics often prescribed for preventing UTIs. In urine below pH 5.5, methenamine releases formaldehyde, which is antibacterial. Methenamine mandelate, 1 g four times daily, or methenamine hippurate, 1 g twice daily by mouth, is used as a urinary antiseptic to suppress UTI. Acidifying agents may be given to lower urinary pH (^{Katzung, 2007}). Because methenamine is not an antibiotic, bacterial resistance is not an issue. Earlier studies, such as the one done by Banovac and colleagues, showed methenamine therapy to be effective in prevention of UTI in patients with SCI and neurogenic bladder dysfunction (^{Banovac, 1991}). However, more recent studies have not showed significant effectiveness of methenamine in preventing UTIs (^{Lee et al., 2007}). More research is recommended to determine if methenamine could decrease encrustations in long-term catheterized patients who have frequent obstructions (^{Gould et al., 2009}).

Bacterial Interference

There have been some trials of using bacterial interference (bladder inoculation with a nonpathogenic bacterial strain) for prevention of UTI. In one study, a nonpathogenic strain of Escherichia coli (83972) significantly impeded catheter colonization by bacterial pathogens (^{Trautner et al., 2003}). The Centers for Disease Control and Prevention recommend further research in regard to the ability of this procedure to prevent UTI in patients requiring chronic urinary catheterization (^{Gould et al., 2009}).

Diagnosing and Treating Urinary Tract Infection

Despite best efforts to avoid infection, people with SCI and neurogenic bladder often develop UTIs. When symptoms of a UTI develop in a person who is catheterized, a urinalysis and/or urine culture and sensitivity are usually done to confirm that the symptoms are from urinary infection rather than some other cause. When obtaining specimens for laboratory testing, it is important to change the indwelling catheter before collecting the specimens. Changing the catheter before collecting urine improves the accuracy of urine culture results (^{Trautner, 2004}). Formation of biofilms by urinary pathogens on the surface of the catheter and drainage system occurs universally with prolonged duration of catheterization (^{Gould et al., 2009}). The longer the catheter remains in place, the greater the tendency of these organisms to develop biofilms. These microorganisms are highly resistant and are tenaciously bound to the inner or outer surfaces, and result in UTIs. Microorganisms can migrate to the bladder on biofilm, either along the outside of the catheter or along the inside of the catheter if the drainage bag or tubing has become contaminated (^{Rhinehart & McGoldrick, 2006}). Urine bags should be changed regularly, but there is no official recommendation for how often a urinary drainage bag should be changed (^{Talsma, 2007}). The indwelling urinary catheter should be replaced before collecting urine specimens for laboratory testing. This may improve the response to antibiotic therapy by removing the biofilm that probably contains the infecting organisms, which can result in reinfection (^{Trautner, 2004}). The biofilm provides a reservoir for microorganisms, and the protective properties of it hinder the effectiveness of antibiotics (^{Talsma, 2007}). Specimens should never be collected from urine that has been sitting in a drainage bag.

Laboratory isolation of more than one bacterial species in the general population is usually considered to indicate contamination, but such a finding in patients with SCI may not be true. Almost half of positive urine cultures in patients with SCI yield multiple microorganisms, and this finding is particularly prevalent in patients who have chronic indwelling catheters (^{Darouiche, 2003}).

The healthcare provider should be notified when the patient develops fever, or if symptoms of infection are causing problems, for a possible order of antibiotic therapy. The type of drug used and the duration of treatment depend on the type of bacteria and severity of infection. Ideally, antibiotic treatment should be based on the culture and sensitivity report, but empiric treatment with a broad-spectrum antibiotic such as sulfamethoxazole/trimethoprim or ciprofloxacin is often initiated. For patients with high fever (102–104° F or 38.9–40° C [^{Zieve, 2009}]), dehydration, or autonomic dysreflexia, more aggressive therapy may need to be instituted, such as intravenous antibiotics and fluids. Although studies in nondisabled individuals indicate that short courses of oral antibiotics are effective in eradicating uncomplicated lower UTI, these results may not hold true for the SCI population (^{Darouiche, 2003}). Antibiotic therapy is often prescribed for a 10- to 14-day course. Patients or caregivers should be instructed in the importance of completing the full course of antibiotics prescribed, to reduce the growth of resistant organisms.

Conclusion

Many factors contribute to the altered functioning of the urinary system following SCI. These all play a part in increasing the risk of UTI among patients with SCI. The home healthcare nurse can assist in the prevention of infection by performing careful hand hygiene, by observing aseptic technique in catheter changes, and by educating patients and their family or caregivers in ways they can minimize the risk for UTI. Although SCI patients, in particular, are described, much of the material covered is applicable to any type of neurogenic bladder dysfunction.

Considerations include:

Type of post SCI bladder (i.e. reflex or flaccid, DSD)

Level and completeness of SCI

Gender of the patient

Physical barriers (i.e. weight, manual dexterity)

Availability of family/caregivers and/or home health services to assist in carrying out the method chosen

Patient's preferences

Signs and symptoms of UTI

Discomfort or pain over the kidney or bladder (though this may be absent in insensate patients)

Cloudy, dark, and/or malodorous urine

Onset of urinary incontinence or leaking around the catheter

Increased spasticity;

Malaise and lethargy

Anorexia

Autonomic dysreflexia;

Fever/chills may develop when the infection has reached the upper urinary tract