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Home > RNJ > 2006 > July/August > Intrathecal Baclofen Therapy: Challenges in Patients with Multiple Sclerosis

Intrathecal Baclofen Therapy: Challenges in Patients with Multiple Sclerosis
Barbara Ridley, MS RN FNP APRN-BC CRRN

 

Intrathecal baclofen (ITB) is a recognized therapy for severe spasticity of both spinal and cerebral origin, with documented positive clinical outcomes for many patients with multiple sclerosis (MS). This article reviews some specific considerations concerning the use of ITB in the MS population, based on the author’s 10 years of clinical experience. The unpredictable and progressive nature of the disease affects the identification of appropriate goals, the patient’s decision-making process, and the evaluation of the response to the treatment over time. Patients with MS may be more sensitive to intrathecal baclofen than patients with other diagnoses, and may need a lower dose for both the screening test and maintenance therapy. Subtle cognitive changes may affect the patient’s ability to understand the education needed for successful management of ITB. Some practical strategies are offered for the nurse involved in the care of these patients in each stage of the therapy.

Intrathecal baclofen (ITB) therapy has been approved by the Food and Drug Administration as a treatment for severe spasticity of both spinal and cerebral origin. (Albright et al., 2003; Ivanhoe, Tilton, & Francisco, 2001). Spasticity may lead to a myriad of problems and complications, including pain, contractures, or difficulties with positioning, ambulation, transfers, performance of basic hygiene measures, or the wearing of orthotic devices (Rizzo, Hadjimichael, Preiningerova, & Vollmer, 2004). Since the early 1990s ITB, or the “baclofen pump,” has been successfully used in thousands of patients throughout the nation and elsewhere, with documented positive clinical outcomes (Middel et al., 1997; Staal, Arends, & Ho, 2003; Stempien & Tsai, 2000). Many of these patients have spasticity related to multiple sclerosis (MS), in both the relapsing-remitting and progressive forms of the disease. ITB has been clearly shown to benefit these patients (Bethoux, Stough, & Sutliff, 2004; Jarrett et al., 2001; Ordia, Fischer, Adamski, Chagnon, & Spatz, 2002; Rawlins, 2004).

However, there are some unique challenges in the use of ITB therapy with the MS population. The author is an advanced practice nurse with experience in coordinating a large ITB therapy center, providing direct clinical care to ITB patients with MS and other diagnoses and participating in forums with other ITB therapy providers throughout the country. The issues addressed here emerge from this clinical experience and emphasize the nursing implications throughout the various stages of the therapy.

ITB therapy is traditionally seen as comprising four distinct stages: patient selection, screening test, surgical implantation, and on-going medical management (Laborde, Wiebel, Meythaler, & Narayan, 1999). Unlike many other neurological disorders that cause severe spasticity (e.g., cerebral palsy, traumatic spinal cord injury, brain injury, or stroke) multiple sclerosis is a progressive disease with a variable, unpredictable course. This has an effect in each stage of the therapy. In addition, clinical experience has shown that patients with MS tend to be more sensitive to the potential side effects of ITB and may need to have adjustments made in dosing decisions to take this into account. Because ITB therapy is long term and requires on-going maintenance, nurses will have opportunities to work with patients and their families as the disease progresses. Nurses need to provide effective interventions and education for each phase. This article outlines each stage of ITB therapy, and it identifies and addresses specific issues related to MS that nurses need to understand.

Patient Selection

Patients are considered candidates for ITB therapy if they have severe spasticity that is causing significant impairment and has proven to be unresponsive to more conservative therapies such as oral medications, physical therapy, and local injection therapy (Zahavi, Geertzen, Middel, Stahl, & Rietman, 2004). Every patient requires a realistic on-going management plan and identification of individualized, realistic goals for the therapy. During this stage, the nurse’s role is to spend time educating the patient and family members to avoid pitfalls and disappointment later on.

Patients and family members will often question why ITB is being considered when the patient has failed on oral baclofen in the past. Oral form failures are due to intolerable side effects or ineffective spasticity relief. The nurse will explain that with the baclofen pump the medication is delivered through a small catheter directly into the cerebrospinal fluid and can act on the gamma-aminobutyric acid receptor sites in the spinal cord. This method achieves a response with a much lower dose than with the oral route and minimizes side effects. A typical intrathecal dose is one-hundredth or less of the oral dose and is much more effective in controlling spasticity.

In the author’s experience, patients with MS will also have concerns about whether their spasticity or their underlying disease is really “bad” enough for something as invasive as intrathecal baclofen. The patient will not be considered a candidate unless more conservative measures have failed, and yet there is often a psychological hurdle to overcome that entails a degree of acceptance of the diagnosis of MS that may have been denied on some level. ITB can be an effective treatment for patients in any stage of MS, and can greatly improve the lives of those with advanced progressive disease. However, it may often be a mistake to wait until that stage to initiate therapy; the patient may lose function or develop secondary complications that could have been avoided if the spasticity had been effectively controlled earlier. Assisting the patient and appropriate family members to understand and accept this may require extensive education and counseling over time, best performed within the context of a therapeutic clinical relationship.

Identifying and agreeing on realistic, achievable goals for ITB therapy for each patient is an important element of the patient selection stage. Goals can vary, depending on the underlying neurological condition and the impact of the spasticity and can range from improving ambulation to easing care-giving tasks in totally disabled patients (see Table 1). Providers must be clear about what is feasible as a goal for each individual and make sure that both the patient and family members understand that the baclofen pump is not going to be a cure for MS, and it is not going to address other neurological or motor problems such as weakness, paralysis, and tremor. In appropriately selected patients, ITB therapy can be fairly reliably predicted to reduce spasms, tone, rigidity, clonus, and spasticity-related pain. It can also greatly reduce or eliminate the need for oral antispasmodic agents, thereby relieving troublesome side effects (Ordia et al., 2002). Other goals, such as better quality of gait, improved bladder function, or increased control of upper extremities, may be achievable yet difficult to predict in individual patients. Although some patients achieve dramatic improvements in function and quality of life with ITB therapy, it is prudent to be cautious about encouraging unrealistic expectations.

In the patient-selection stage, it may be beneficial to invite the patient or relevant family members to talk to someone who already has the pump in place, who can speak from personal experience, and answer questions and concerns. Large centers can find an appropriate peer match from their own caseloads, but for smaller facilities the pump manufacturer (Medtronic) offers an ambassador program to link potential patients with someone of a similar age and diagnosis. Care must be taken however, not to unwittingly encourage unrealistic hopes, for example, in a non-ambulatory patient with MS who talks to someone whose pump has made it possible for him to walk without an assistive device. On the other hand, exposure to someone with much more advanced disease may generate the fear that the baclofen pump has caused the increasing disability. Careful selection of an appropriate match can make this a beneficial experience for all concerned.

Screening Test

Patients who are selected as appropriate candidates for ITB therapy and who wish to proceed are scheduled for a screening test. This is when a one-time bolus injection of ITB (usually 50 mcg in 1 cc) is administered by lumbar puncture and the patient’s response is observed over an 8-hour period. If the patient has a drop in the Ashworth scale scores in the affected extremities, this is considered a positive response and indication that he or she will benefit from implantation of the pump (Francisco, 2001). The Ashworth scale measures tone or resistence to passive stretch in the extremities, using a 5-point scale (Ashworth, 1964). Many patients experience dramatic relief of spasticity about 3 or 4 hrs after the baclofen injection, and some notice significant improvement in functional tasks such as transferring to a wheelchair, ability to tolerate a seated position, or improved comfort wearing an orthotic device such as an ankle-foot orthosis.

However, patients must be warned that the screening test is not an accurate demonstration of the functional benefit that is likely to be achieved after the pump is implanted. The author describes the screening test to patients as a “one-size-fits-all” dose of ITB, whereas the pump can be programmed to release an individually determined dose of the medication. In many patients, the relief of spasticity unmasks underlying muscle weakness. This may respond to strengthening and new motor learning over time, but may initially lead to increased difficulty with some tasks. The dose at the screening test may turn out to be too high for a particular patient, leaving him too hypotonic or “floppy,” causing knees to buckle with weakness when he tries to stand or transfer. Patients with MS, particularly if they are ambulatory, appear to be especially susceptible to this effect. They may be particularly frightened by this response because of their fear of disease progression. It can be difficult to persuade these patients that ITB therapy will benefit them, even if they were instructed about this in advance. With these considerations in mind, some providers lower the standard 50 mcg screening test dose to 25 mcg for ambulatory MS patients.

Patients with MS may also be susceptible to a prolonged response to the effect of the medication. The patient usually returns to baseline within about 8 hrs of receiving the one-time bolus of intrathecal baclofen. However, patients should be carefully monitored and evaluated for readiness for discharge at that time, especially if they have become hypotonic and if they need some spasticity to perform essential functions such as transfers. Some individuals with MS have been known to retain effect for up to 24 hrs or even longer. These patients are very sensitive to ITB, and will likely do well on extremely low doses after the pump is implanted.

Surgical Implantation

If the patient has a positive response to the screening test and wishes to proceed, arrangements are made for the surgical implantation of the pump and spinal catheter. This may be done as an in-patient or out-patient procedure, with general or modified anesthesia. Although there are always risks associated with any surgical intervention, pump implantation is considered to be a minor procedure with few complications in an experienced practitioner’s hands. Patients with MS may need reassurance about this and reassurance that there is no known risk of exacerbating the disease with this procedure (Bethoux et al., 2004). In patients with more advanced MS, it is important to make sure that there is no urinary tract infection (UTI), skin breakdown, depleted nutritional state, or other significant comorbidity that may affect recovery after surgery.

After the implantation of the device, the patient will require detailed instruction about the pump model, reservoir size, drug dose and concentration, follow-up appointments, and precautions to observe, in addition to the routine post-op wound instructions. There is usually a titration period when ITB therapy is initiated, with the dose being gradually increased as the patient’s response is evaluated. The patient may need to continue on some oral antispasmodic agents during this time. Discharge instructions need to cover the signs and symptoms of overdose and acute withdrawal from ITB. Although these are rare occurrences, they may be potentially life-threatening (Coffey et al., 2002; Ivanhoe et al., 2001). The nurse will need to ensure that the patient has a clear understanding of what to look for and whom to call.

One concern that arises with MS patients is the possibility of cognitive changes that may affect their ability to comprehend and retain the discharge instructions. Cognitive dysfunction is a common problem in MS (Halper et al., 2003), yet it may be subtle and partially masked by compensatory strategies utilized by patients in an effort to appear as normal as possible. Nurses need to be vigilant in their assessment of the patient’s ability to learn and retain information from one session to the next. It is important to identify the most appropriate family members or other support people to include in the discharge teaching, while continuing to allow the patient to be fully involved and in as much control as possible.

Post-implant Titration Period

The titration period, during which the ITB dose is gradually adjusted to optimize response to the treatment, may be started during a brief in-patient stay, but will usually take from weeks to months to complete. This is done in an out-patient setting (Francisco, 2001). Patients are monitored for reduction in tone and spasticity and the occurrence of any adverse drug effects such as weakness, somnolence, nausea, or bowel or bladder dysfunction. Most patients will benefit from rehabilitation therapy during this period (Barry, Albright, & Shultz, 2000). With the spasticity reduced, physical therapy can increase muscle strength, facilitate new motor learning, or modify orthotic devices. Occupational therapy may be helpful with wheelchair seating and positioning, adaptive devices, and the potential for new daily living activities with improved upper extremity control. Some patients may need speech therapy if the spasticity has been affecting vocal cord or oral motor control (Bjornson et al., 2003). Patients with MS are particularly likely to benefit from an interdisciplinary approach, where there is good coordination between the therapists and open communication with the provider responsible for making adjustments in the ITB dosing. Nurses may be in a position to ensure that this coordination is effective.

When ITB treatment is first initiated, it is common practice to program the pump to administer a simple continuous infusion of the medication, with a small dose given at a consistent rate over a 24-hour period. The patient’s response to the screening test dose will guide providers as they choose the starting dose. If the patient had a good response to the 50 mcg screening bolus injection, the pump may typically be started at a continuous infusion of 100 mcg a day. However, if the patient became hypotonic with a 50 mcg bolus, the initial ITB dose selected should be much lower, perhaps as low as 50 mcg a day. Patients with MS are particularly likely to benefit from a “start low, go slow” approach. With other diagnoses, it is possible to increase the ITB dose over the first few days or weeks by 10%–20% increments in order to bring the spasticity under control. Patients with MS may be sensitive to dose increases, with some responding to much smaller dose changes, perhaps as little as 5% or less. There is a great range in the ITB dose at which patients eventually stabilize, from as low as 40 mcg a day to 1500 mcg or even higher, but most patients with MS respond well at the lower end of this range (Rawlins, 2004).

Some MS patients may need a certain amount of tone to maintain trunk balance while seated or leg stability during transfers and walking. This can be handled by making gradual increases, and allowing time for the patient to build up muscle strength in physical therapy. However, many MS patients benefit from the pump’s ability to be programmed to give a lower dose during the day when some degree of spasticity can provide functional advantage, but then increase the dose during the night to provide more comfort in bed. This is the complex continuous or flex dosing mode. The newest model of the pump allows for this dosing to reflect different bed times and rising times on the weekends. The patient and family, together with the treating therapists, nurses and physicians, have to learn how to monitor the response to these dose modifications and determine the best regimen for the patient using an empirical approach and an interdisciplinary partnership.

During the early titration period, the nurse needs to be alert for any adverse effects with bowel or bladder function. Although intrathecal baclofen primarily affects striated muscle and will have minimal effect on smooth muscle function in many patients, changes in smooth muscle function have been noted (Laborde et al., 1999; Meythaler, Guin-Renfroe, Brunner, & Hadley, 2001; Stempien & Tsai, 2000). For many patients with MS, there will be a positive effect on the bladder, with a decrease in urgency and increase in bladder capacity. Patients need to be monitored, however, for the development of urinary retention. The effect of ITB may be to increase post-void residuals to the point where they need intermittent catheterization. Sometimes this can be avoided by decreasing the ITB dose and then increasing it gradually later (Meythaler et al.). Patients with advanced progressive disease may be susceptible to an increase in constipation with ITB, that can usually be managed by more rigorous bowel training.

On-going Management

After patients have stabilized their ITB dose, follow-up will occur less frequently, and will occur mainly for refill of the pump medication reservoir. Refills will be required every 1–6 months, depending on dose and pump size. Patients and family members need to understand the importance of keeping track of when the refill is due because allowing the reservoir to run dry may precipitate serious symptoms of baclofen withdrawal (Coffey et al., 2002). Refills are usually scheduled when the reservoir volume gets to just over 2 cc. The pump may not function as accurately if the volume drops lower than this, although the newer model is reported to be accurate with the volume down to 1 cc (Medtronic Inc., 2004). However, patients with MS may notice reduced efficacy of the treatment at higher volumes; they may be sensitive to the feeling of running low when the volume gets to 3 cc, and may need to have their refills scheduled accordingly.

Patients develop a long-term relationship with the clinic or office where these refills are performed, and the nurse in this type of setting becomes an important clinical resource for the patient. With MS this may mean following the patient through disease progression and increasing disability and modifying the ITB treatment accordingly. Patients with MS may experience more fluctuations in their level of spasticity than those with other, more stable etiologies, and may require more frequent adjustments even after the initial titration period has been completed. Their spasticity may be sensitive to changes in weather and level of stress in their lives, in addition to more tangible irritating factors such as infections or skin breakdown. UTIs are common in this population and are known to increase spasticity. In fact, increased spasticity may be the presenting symptom of a UTI in a patient with MS. This should always be ruled out before any adjustments are made to the ITB dose.

Another issue that may arise is the patient’s need to exert control within the context of an unpredictable, uncontrollable disease by making unreasonable demands for frequent ITB dose adjustments to chase fluctuations in symptoms. The nurse can provide support that allows the patient to feel in as much control as possible while setting some reasonable limits on dose changes.

An increase in spasticity over time may be a manifestation of disease exacerbation or progression in a patient with MS. However, there may be other factors involved. Antidepressant medications, especially the selective serotonin reuptake inhibitors, have been shown to increase spasticity in patients with MS and other neurological conditions (Stolp-Smith & Wainberg, 1999). They are commonly prescribed by providers unaware of this effect. Spasticity may also increase with the addition of interferons as disease-modifying therapy in MS (Calabresi, 2002). On the other hand, some medications prescribed for neuropathic pain, another common symptom in MS, may have some antispasmodic action, so may require a reduced ITB dose to avoid hypotonia. Bladder function may change over the years or may be affected by changes in the ITB dose. Addressing these issues requires a comprehensive approach—consideration of the underlying disease as well as drug interactions and the presence of unrelated comorbidities. Communication between all providers involved in the patient’s care is essential to maintain the most effective use of ITB therapy.

Patients must be taught to report any sudden marked increase in spasticity, as this may signal failure of the pump or the catheter system. Providers need to identify the source of the problem and provide coverage with oral medications to prevent a withdrawal syndrome. Providers must also be aware of the fact that more gradual or subtle increases in spasticity can turn out to be small catheter leaks, displacements or position-dependent occlusions (Turner, 2004; Vaidyanathan et al., 2003). With patients with complex and unstable conditions such as MS, clinicians must be careful not to assume that changes in the disease or related symptoms are always responsible for changes in spasticity, when there could be a catheter problem.

The pump has a battery with a life of approximately 7 years. As this time approaches, patients must plan for how the battery will be replaced and what to do in the event of a low-battery signal from the pump. Patients with advanced progressive MS may have a fragile health status, and the nurse may need to discuss whether an elective pump replacement should be planned shortly prior to the expected end of battery life. After the alarm goes off, the pump must be replaced within 1–2 weeks, and some patients may have complicating factors such as acute infections present at that time. The alarm on the older model pumps is barely audible for many patients, especially if there is equipment such as a low air-loss mattress in the home. This needs to be taken into account when planning pump replacement.

Patients and family members must be involved as educated partners in the on-going management of ITB, and the healthcare providers managing the pump have to be flexible and respond to changes in the patient’s living situation, family dynamics, insurance coverage, and overall disability and health status. Nurses involved in the long-term management of MS patients with ITB must be alert to the possibility of cognitive function deteriorating over time, and the effect this may have on the patient’s ability to remember refill appointments, what they were told about pump management, or to accurately report significant changes in symptoms. Family members or other caretakers may need to become more involved as time progresses.

Conclusions

ITB therapy can be of tremendous benefit to patients with MS, allowing their spasticity to be effectively controlled with minimal side effects and maximizing function and preventing complications for as long as possible. It has been shown to improve overall quality of life for these patients, controlling painful spasms, improving transfers, positioning, sleep, and the ability to perform activities of daily living (Gianino, York, Paice, & Shott, 1998; Jarrett et al., 2001; Rizzo et al., 2004). Patients with MS express high satisfaction with ITB treatment (Bethoux et al., 2004). However, the nurse needs to be aware of some of the unique challenges associated with the use of this therapy in the MS population, in order to contribute to its successful management (see Table 2). Patients need to be carefully selected for this therapy, with individualized goals appropriately identified. Modifications in the screening test dose and the initial starting dose of ITB therapy may need to be made, because patients with MS are sensitive to this medication. Pump management requires a long-term commitment on the part of both the patient and the provider and an on-going evaluation of the patient’s response while managing their complex health needs.

Barbara Ridley, MS RN FNP APRN-BC CRRN, is a nurse practitioner at the Spasticity Management Clinic, Alta Bates Summit Medical Center in Berkeley, CA. Address correspondence to her at 2001 Dwight Way, Suite 2350, Berkeley, CA, 96704; ridleyb@sutterhealth.org.

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