Death after acute withdrawal of intrathecal baclofen: case report and literature review

Intrathecal baclofen withdrawal: emergent recognition and management

Patients with severe spasticity are frequently encountered in the pediatric emergency department. Intrathecal baclofen therapy is being used increasingly to treat these patients. The purpose of this case series is to illustrate the importance of early recognition and treatment of intrathecal baclofen withdrawal, a potentially life-threatening complication of intrathecal baclofen therapy. Four cases of intrathecal baclofen withdrawal are presented.

A benefit-risk assessment of baclofen in severe spinal spasticity

Baclofen is used for treatment of the spasticity of spinal origin that is a common sequela of spinal cord injury and multiple sclerosis; spasticity occurs in about 50% of patients affected by these disorders. In open-label studies of oral baclofen, the drug improved spasticity in 70-87% of patients; additionally, improvement in spasms was reported in 75-96% of patients. In double-blind, crossover, placebo-controlled trials, baclofen was reported to be effective, producing statistically significant improvements in spasticity. Tizanidine is the antispasticity drug that has been most widely compared with oral baclofen; studies have generally found the two drugs to have equivalent efficacy. However, tizanidine has better tolerability, in particular weakness was reported to be occur less frequently with tizanidine than with baclofen. The main adverse effects of oral baclofen include: sedation or somnolence, excessive weakness, vertigo and psychological disturbances. The incidence of adverse effects is reported to range from 10% to 75%. The majority of adverse effects are not severe; most are dose related, transient and/or reversible. The main risks of oral baclofen administration are related to withdrawal: seizures, psychic symptoms and hyperthermia can occur. These symptoms improve after the reintroduction of baclofen, usually without sequelae. When not related to withdrawal; these symptoms mainly present in patients with brain damage and in the elderly. The limited data on baclofen toxicity in patients with renal disease suggest that administration of the drug in these persons may carry an unnecessarily high risk. Intrathecal baclofen is indicated for use in patients with spasticity of spinal origin unresponsive to treatment with maximum doses of oral baclofen, tizanidine and/or dantrolene. The benefits of continuous intrathecal baclofen infusion have been demonstrated: >80% and >65% of patients have improvement in tone and spasms, respectively. The main risks of intrathecal baclofen infusion are symptoms related to overdose or withdrawal; the latter is more important because of the associated severe effects on clinical status and the possibility of death, but it is responsive to rapid treatment. Overdose primarily arises from drug test doses or human error during refill and programming of the pump, and withdrawal most commonly occurs as a result of a problem with the delivery system. Since the adverse consequences do not exceed the benefits of oral and intrathecal baclofen for patients with spinal spasticity, the benefit/risk assessment is favourable.

Treatment of spasticity with intrathecal Baclofen administration: long-term follow-up, review of 40 patients

STUDY DESIGN

Case series of a consecutive sample. Retrospective audit.

OBJECTIVE

To analyze the long-term safety and efficacy of intrathecal baclofen (ITB), and technical incidents.

SETTING

Neurosurgical and Physical Medicine Departments of two university hospitals in western France.

METHODS

The medical records of 40 patients who underwent ITB pump placement for the treatment of severe chronic spasticity were reviewed. Patients were eligible independently of the origin of the spasticity (spinal cord origin 33, brain damage 8). They underwent a final assessment with clinical examination and questionnaire in 2001. Ashworth scale scores were assessed, patient satisfaction was rated on a visual analog scale (VAS), functional independence before and after treatment was classified as bed-ridden, wheelchair dependent or ambulant, and the frequency and nature of complications were noted.

RESULTS

The average follow-up period was of 4 years. The average Ashworth score at the final assessment was 1.8+/-0.6. Average patients satisfaction was 7.4/10+/-2.21 on VAS. In all, 85% would have undergone the procedure again if they had to make the decision. In 85% of the cases the ambulation status was unchanged. Technical incidents occurred at least once in 37% of the patients (due to the catheter in 58% and to the pump in 42%). They included catheter disconnections (4), migration (4), kinks (3), obstruction (3), development of fibrosis (3), disconnection of pump reservoir (2), porosity of pump membrane (2), unexplained pump dysfunction (4) leakage, and subcutaneous collection (5). Severe pharmacological side effects requiring transfer to intensive care unit occurred in 12% of cases, 80% of which were directly related to pump refill procedures.

CONCLUSION

ITB remained effective in the long term and patients were satisfied. Nevertheless, complications were frequent, involving mainly the catheters, which would require further technical improvements.

Intrathecal baclofen withdrawal syndrome- a life-threatening complication of baclofen pump: a case report

Background

Intrathecal baclofen pump has been used effectively with increasing frequency in patients with severe spasticity, particularly for those patients who are unresponsive to conservative pharmacotherapy or develop intolerable side effects at therapeutic doses of oral baclofen. Drowsiness, nausea, headache, muscle weakness, light-headedness and return of pretreatment spasticity can be caused by intrathecal pump delivering an incorrect dose of baclofen. Intrathecal baclofen withdrawal syndrome is a very rare, potentially life-threatening complication of baclofen pump caused by an abrupt cessation of intrathecal baclofen.

Case presentation

A 24-year-old man with a past medical history of cerebral palsy and spastic quadriparesis developed hyperthermia, disseminated intravascular coagulation, rhabdomyolysis, acute renal failure and multisystem organ failure leading to a full-blown intrathecal baclofen withdrawal syndrome. Intrathecal baclofen pump analysis revealed that it was stopped due to some programming error. He was treated effectively with supportive care, high-dose benzodiazepines and reinstitution of baclofen pump.

Conclusion

The episodes of intrathecal baclofen withdrawal syndrome are mostly caused by preventable human errors or pump malfunction. Educating patients and their caregivers about the syndrome, and regular check-up of baclofen pump may decrease the incidence of intrathecal baclofen withdrawal syndrome. Oral baclofen replacement may not be an effective method to treat or prevent intrathecal baclofen withdrawal syndrome. Management includes an early recognition of syndrome, proper intensive care management, high-dose benzodiazepines and prompt analysis of intrathecal pump with reinstitution of baclofen.

Correlation between Withdrawal Symptoms and Medication Pump Residual Volume in Patients with Implantable SynchroMed Pumps

OBJECTIVE:

To investigate whether patients with implantable SynchroMed pumps (Medtronic, Inc., Minneapolis, MN) develop symptoms of drug withdrawal at residual medication volumes that exceed 2 ml (the alarm residual volume recommended by the manufacturer).

METHODS:

The data sheets of 88 patients with implantable SynchroMed pumps were retrospectively reviewed. The following parameters were analyzed: development of symptoms of drug withdrawal; drugs used in the pump; disease state; drug residual volume in the pump; intake of orally administered medications; time of development of withdrawal symptoms; drug flow volume through the pump; daily intrathecally administered drug dose; and drug concentration in the pump.

RESULTS:

Of 88 patients, 21 (24%) consistently developed symptoms of drug withdrawal 1 to 7 days before the drug residual volume reached a mean of 2.7 ml (range, 2.1–3.8 ml; median, 2.6 ml). Symptoms first developed 1 to 18 months after surgery. In all patients, symptoms of drug withdrawal subsided after pump refill and did not recur after the alarm volume was increased to 4 ml. Symptom development did not correlate with intake of orally administered medication, drug flow volume through the pump, intrathecally administered drug dose, drug concentration in the pump, drugs used in the pump, or disease state.

CONCLUSION:

Some patients develop symptoms of drug withdrawal at residual volumes that exceed 2 ml. We could not identify factors that predict this occurrence. Withdrawal symptoms did not recur when the alarm volume was increased to 4 ml.

Respiratory Distress After Intrathecal Baclofen Withdrawal

We present the case of a 19-yr-old woman with a history of generalized dystonia who developed sudden onset of adductor spasms of the vocal cords and increased dystonia after the interruption or intrathecal baclofen therapy. Her symptoms resolved after intrathecal baclofen was restored. In patients with dystonia receiving intrathecal baclofen therapy, the onset of dyspnea associated with increased muscle tone should prompt the investigation of baclofen withdrawal.

Approach to the rehabilitation of spasticity and neuromuscular disorders in children

The management of children and adults with upper motor neuron disorder is complex and multifaceted. This article reviews new information and potential treatment. As part of the upper motor neuron syndrome (UMNS), spasticity may occur in cerebral palsy, congenital brain malformation, head injury, or other etiologies. Within the UMNS the most recognizable clinical concern is the frequent abnormality of tone, which may have a significant functional impact. Tone reduction is not itself a goal, but is performed for the functional benefits it may allow. New approaches to treatment and management of hypertonia recently have become available. There are many other associated features of the UMNS that affect patient functioning. Ones that frequently occur are abnormalities of speech and other areas of oral motor control. A new area of intervention combines the use of botulinum toxin and ultrasonography to address the common problem of slalorrhea, which is a potential medical issue and a substantial social barrier in affected patients. This article also reviews new information and potential treatment for neuromuscular disorders.

Cyproheptadine for intrathecal baclofen withdrawal

OBJECTIVE

To evaluate the efficacy of cyproheptadine in the management of acute intrathecal baclofen (ITB) withdrawal.

DESIGN

Descriptive case series.

SETTING

University hospital with a comprehensive in- and outpatient rehabilitation center.

PARTICIPANTS

Four patients (3 with spinal cord injury, 1 with cerebral palsy) with implanted ITB infusion pumps for treatment of severe spasticity, who had ITB withdrawal syndrome because of interruption of ITB infusion.

INTERVENTIONS

Patients were treated with 4 to 8mg of cyproheptadine by mouth every 6 to 8 hours, 5 to 10mg of diazepam by mouth every 6 to 12 hours, 10 to 20mg of baclofen by mouth every 6 hours, and ITB boluses in some cases.

MAIN OUTCOME MEASURES

Clinical signs and symptoms of ITB withdrawal of varying severity were assessed by vital signs (temperature, heart rate), physical examination (reflexes, tone, clonus), and patient report of symptoms (itching, nausea, headache, malaise).

RESULTS

The patients in our series improved significantly when the serotonin antagonist cyproheptadine was added to their regimens. Fever dropped at least 1.5 degrees C, and heart rate dropped from rates of 120 to 140 to less than 100bpm. Reflexes, tone, and myoclonus also decreased. Patients reported dramatic reduction in itching after cyproheptadine. These changes were associated temporally with cyproheptadine dosing.

DISCUSSION

Acute ITB withdrawal syndrome occurs frequently in cases of malfunctioning intrathecal infusion pumps or catheters. The syndrome commonly presents with pruritus and increased muscle tone. It can progress rapidly to high fever, altered mental status, seizures, profound muscle rigidity, rhabdomyolysis, brain injury, and death. Current therapy with oral baclofen and benzodiazepines is useful but has variable success, particularly in severe cases. We note that ITB withdrawal is similar to serotonergic syndromes, such as in overdoses of selective serotonin reuptake inhibitors or the popular drug of abuse 3,4-methylenedioxymethamphetamine (Ecstasy). We postulate that ITB withdrawal may be a form of serotonergic syndrome that occurs from loss of gamma-aminobutyric acid B receptor-mediated presynaptic inhibition of serotonin.

CONCLUSION

Cyproheptadine may be a useful adjunct to baclofen and benzodiazepines in the management of acute ITB withdrawal syndrome.

Intrathecal baclofen withdrawal mimicking sepsis

Baclofen (Lioresal) is a drug of choice to treat spasticity and is increasingly being administered intrathecally via an implantable pump in cases refractory to oral therapy. Emergency physicians will likely treat patients with baclofen withdrawal or overdose as this treatment becomes more widespread. The syndrome of baclofen withdrawal presents with altered mental status, fever, tachycardia, hypertension or hypotension, seizures, and rebound spasticity, and may be fatal if not treated appropriately. Baclofen withdrawal may mimic other diseases including sepsis, meningitis, autonomic dysreflexia, malignant hyperthermia, or neuroleptic malignant syndrome. Treatment consists of supportive care, reinstitution of baclofen, benzodiazepines, and diagnosis and eventual repair of intrathecal pump and catheter malfunction.

Intrathecal baclofen therapy in children with cerebral palsy: efficacy and complications

OBJECTIVES

To describe the efficacy of intrathecal baclofen (ITB) therapy in the management of spasticity in young children with cerebral palsy (CP) and to identify risk factors for complications.

DESIGN

Consecutive case series of 25 implanted ITB delivery systems during a 48-month period.

SETTING

Pediatric specialty hospital and outpatient department.

PARTICIPANTS

Twenty-three children (age range, 4.5-17.4y) with CP (spastic diplegia in 22%; spastic quadriplegia in 61%; mixed-type diplegia in 4%; mixed-type quadriplegia in 13%).

INTERVENTION

Intrathecal baclofen therapy in children with cerebral palsy.

MAIN OUTCOME MEASURES

Ashworth Scale scores before treatment and at 6 and 12 months after ITB therapy; frequency and nature of complications; and relation between patient characteristics and outcomes.

RESULTS

Average Ashworth scores +/- standard deviation decreased from 3.26+/-.73 to 2.34+/-.83 (P<or=.01) in the lower extremities and from 2.69+/-.79 to 2.00+/-.55 (P<or=.05) in the upper extremities 6 months after ITB therapy and remained comparably decreased at 12 months. Explantation was required in 44% (11/25), with wound complications as the leading cause in 73% (8/11). Complications were associated with the diagnosis of mixed-type CP, as compared with pure spastic types (P<or=.01). Trends suggest that children of smaller size and younger age, as well as those with gastrostomy tubes and nonambulatory status, were more likely to encounter complications necessitating explantation.

CONCLUSION

ITB therapy effectively reduced spasticity in children with CP. However, complications necessitating explantation can occur. Further research is needed to identify criteria describing the ideal pediatric candidate for ITB.

Abrupt withdrawal from intrathecal baclofen: recognition and management of a potentially life-threatening syndrome

OBJECTIVE

To suggest guidelines for the prevention, recognition, and management of a life-threatening syndrome (high fever, altered mental status, profound muscular rigidity that sometimes progressed to fatal rhabdomyolysis) in patients who experience the abrupt withdrawal of intrathecal baclofen (ITB) therapy.

DESIGN

Retrospective literature and safety-file review.

SETTING

Expert panel drawn from physiatry, neurology, and neurosurgery.

PARTICIPANTS

Experienced users of ITB therapy in the pediatric and adult populations in the United States.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We reviewed literature reports, MedWatch reports to the US Food and Drug Administration, and our own experiences. We critically analyzed patient management and drug therapy in the context of the pharmacology of baclofen and other antispastic agents.

RESULTS

An abrupt reduction in gamma-aminobutyric acid(B) (GABA) agonist activity in the central nervous system can cause the ITB withdrawal syndrome, which is clinically and pathophysiologically distinct from autonomic dysreflexia, malignant hyperthermia, and neuroleptic-malignant syndrome. ITB withdrawal evolves over 1 to 3 days, but may become fulminant if not recognized and treated early. The syndrome can be interrupted by the restoration of ITB therapy. However, supportive measures and high-dose benzodiazepine infusion may be life saving in the interval before ITB therapy is resumed. Dantrolene infusion may relieve muscle rigidity but does not reverse the other manifestations of GABAergic agonist withdrawal.

CONCLUSIONS

Most episodes of severe ITB withdrawal were preventable. Patients at risk can be identified and educated prospectively and given medication for emergency use. Treatment with GABAergic agonist drugs may prevent potentially fatal sequelae.

Spasticity management: an overview

Recent developments in therapeutic interventions for children with spasticity have complicated managerial decision making. A simplified paradigm for the pathophysiology of spasticity is presented, which emphasizes the ways in which treatment modalities disrupt hyperexcitable segmental spinal reflex arcs. Various techniques for the management of spasticity are reviewed, along with factors relevant to proper patient selection for therapeutic intervention. Potential goals for spasticity management are considered as are outcome measures for assessing the efficacy of these technologies.