Intrathecal baclofen withdrawal simulating neuroleptic malignant syndrome in a child with cerebral palsy

Catatonia and Neuroleptic Malignant Syndrome in Patients With Cerebral Palsy: Two Case Reports and a Systematic Review of the Literature

BACKGROUND

Patients with cerebral palsy, a group of movement disorders with motor, communication, and behavioral features that can mimic catatonic signs, could benefit from efforts to improve the detection and treatment of comorbid catatonia. Given that cerebral palsy frequently co-occurs with conditions associated with catatonia, such as autism spectrum disorder, epilepsy, intellectual disability, and mood and psychotic disorders, lifetime prevalence of catatonia in this population may be high.

OBJECTIVE

This study aimed to systematically review the literature on catatonia and the related condition of neuroleptic malignant syndrome (NMS) in patients with cerebral palsy while presenting 2 additional cases of catatonia.

METHODS

We used the terms "cerebral palsy" in combination with "catatoni∗," related terms for catatonia, and "neuroleptic malignant syndrome" to query Ovid MEDLINE (1948 to November 28, 2022), PsycINFO, Cumulative Index to Nursing, and Allied Health Literature, and Embase for applicable case reports. The Neuroleptic Malignant Syndrome Information Service database was also manually searched.

RESULTS

In addition to our 2 catatonia reports, we identified 10 reports of catatonia in patients with cerebral palsy, as well as 8 reports of NMS. Patients with both conditions responded well, and sometimes rapidly, to treatment. Notably, of the 5 patients with catatonia and cerebral palsy who received electroconvulsive therapy, 2 developed recurrent self-limited hyperthermia posttreatment. We also identified several cases of baclofen withdrawal, which can be life threatening because of seizure risk, presenting with NMS-like features in patients with cerebral palsy who had malfunctioning intrathecal baclofen pumps for spasticity management.

CONCLUSIONS

Given frequent comorbidity of conditions associated with catatonia in patients with cerebral palsy, as well as routine treatment with medications that can induce NMS, such as metoclopramide and anticholinergics, catatonia and NMS may be underreported in the cerebral palsy patient population, despite being highly treatable. Possible underdiagnosis of catatonia in patients with cerebral palsy may be because of misattribution of overlapping features between the 2 conditions to cerebral palsy. Clinicians should be aware of possible recurrent self-limited fever when using electroconvulsive therapy to treat patients with catatonia and cerebral palsy while also being vigilant for intrathecal baclofen withdrawal when encountering NMS-like features in patients with cerebral palsy.

In Support of Initial Parenteral Medical Management of Intrathecal Baclofen Withdrawal in Spasticity Patients

Background: Spasticity may present as a wide range of symptoms and conditions. With this protean presentation, a consensus regarding the best course of treatment does not exist. Those patients most severely affected may receive significant benefit from intrathecal baclofen delivery. However, this therapy may itself lead to patient injury in the event of withdrawal. Objective: Withdrawal from intrathecal baclofen may devolve rapidly into a situation in which the patient may incur significant morbidity and even death. A focused, prompt treatment plan would afford the patient the best possible outcome. Methods: The medical literature was reviewed for reports of plans of treatment of baclofen withdrawal and the results obtained. The nature of this problem does not lend itself to a typical study design, depending on case reports and basic pharmacological science application. The paucity of such reports severely limits categorical comparison of patient characteristics and clinical circumstances. Clinical situations, patient characteristics, and therapies were considered and compared. Outcomes of the varied treatments were evaluated for efficacy. Results: Inaccurate diagnoses, delayed correct diagnoses, and the absence of a consistent, treatment plan contributed to widely disparate outcomes. Prompt, correct diagnosis and intensive care unit-based continuous benzodiazepine infusion with titration led to a controlled clinical situation and maximized patient outcomes. Conclusions: Patients going through withdrawal from intrathecal baclofen achieved best outcomes when treated with a continuous infusion and titration of an intravenous benzodiazepine. A well-defined treatment protocol employing this management, reporting serial outcomes, would enable further refinement of the treatment of this clinical problem.

Lamotrigine, quetiapine and aripiprazole-induced neuroleptic malignant syndrome in a patient with renal failure caused by lithium: a case report

BACKGROUND

Neuroleptic malignant syndrome (NMS) may be induced by atypical antipsychotic drugs (AAPDs) such as aripiprazole, olanzapine, risperidone and quetiapine, either as a single treatment or in combination with other drugs. A case of NMS following the administration of lamotrigine, aripiprazole and quetiapine in a patient with bipolar disorder, and with renal failure caused by toxic lithium levels has not been reported.

CASE PRESENTATION

A 51-year-old female patient with a 27-year history of bipolar disorder, being treated with lithium, fluoxetine, olanzapine, gabapentine, perazine and biperiden, was admitted to the hospital due to depressed mood and delusions. A urinary tract infection was diagnosed and antibiotic therapy was initiated. After 5 days of treatment her physical state deteriorated and she developed a fever of 38.4 °C. Her laboratory results revealed a toxic level of lithium (2.34 mmol/l). Acute renal failure was diagnosed and the lithium was withdrawn. After stabilization of her condition, and despite her antipsychotic treatment, further intensification of delusions and depressed mood were observed. All drugs being taken by the patient were withdrawn and lamotrigine and aripiprazole were initiated. Due to the insufficient effectiveness of aripiprazole treatment and because of problems with sleep, quetiapine was added, however further treatment with this drug combination and an increase of quetiapine to 400 mg/d eventually caused NMS. Amantadine, lorazepam and bromocriptine were therefore initiated and the patient's condition improved.

CONCLUSION

This case report indicates that concurrent use of multiple antipsychotic drugs in combination with mood stabilizers in patients with organic disorders confers an increased risk of NMS development.

Baclofen Withdrawal: A Cause of Prolonged Fever in the Intensive Care Unit

We report a case of baclofen withdrawal syndrome resulting from oral baclofen underdosing. A 24-year-old woman with type 1 neurofibromatosis receiving long-term baclofen therapy was admitted with presumed pneumonia which was successfully treated with antibiotics. The patient continued to have fever and autonomic instability without evidence of infection which entirely resolved within 24 hours of reinstitution of full preadmission dosing of oral baclofen. Baclofen withdrawal syndrome resulting from underdosing of oral baclofen should be considered as a potential source of prolonged fever in the intensive care unit.

Neuroleptic Malignant Syndrome Associated with Valproate in an Adolescent

Neuroleptic malignant syndrome (NMS) is a life-threatening idiosyncratic reaction that usually occurs after the administration of antipsychotic drugs. Antidepressants, benzodiazepines, and antiepileptic drugs are also suggested to be associated with NMS. It is believed to result from a dopaminergic blockade in the central nervous system. NMS is manifested by hyperthermia, muscle rigidity, autonomic dysfunction, altered mental status, leukocytosis, and elevated serum creatinine phosphokinase. Valproate is commonly used in the treatment of many psychiatric and neurologic disorders. Valproate can precipitate NMS, especially when used with antipsychotic drugs concurrently. A 17-year-old male patient, who presented with fever, muscular rigidity, confusion, sweating, and tachycardia was admitted to the emergency room. He had been taking only valproate for the last two months for bipolar disorder. His laboratory analyses revealed raised serum hepatic enzymes, creatinine phosphokinase, and myoglobin levels. Considering fever, rigidity, autonomic dysfunction, cognitive alteration, and high creatinine phosphokinase levels, the patient was diagnosed with NMS. In this paper, we aim to discuss the association between valproate and NMS.

Cardiac arrest due to baclofen withdrawal syndrome

A 41-year-old man presented with postcervical traumatic complete quadriparesis under intrathecal baclofen therapy (ITB) for refractory spasticity. Less than 24 h after having his baclofen pump substituted, he develops hyperthermia, seizures, cognitive depression, acute hypoxaemic respiratory failure and cardiovascular instability leading to mechanical ventilation and vasopressor support. He was transferred to an intensive care unit with diagnosis of community-acquired pneumonia leading to septic shock. He evolved with progressive clinical worsening and multisystem organ failure and cardiac arrest in non-shockable rhythm (pulseless electrical activity)--4 min resuscitation with return of spontaneous circulation. Considering the possible diagnosis of baclofen withdrawal syndrome and, in suspicion of ITB delivery disruption, the catheter system was surgically explored and a leaking tubule attachment was found. Despite aggressive cardiovascular, respiratory and renal support therapy, clinical improvement occurred only after restoration of intrathecal drug delivery. He was discharged from the hospital after 56 days, having returned to baseline status.

Major surgical procedures in children with cerebral palsy

There are 3 surgical procedures that patients with cerebral palsy (CP) undergo that may be considered major procedures: femoral osteotomies combined with pelvic osteotomies, spine fusion, and intrathecal baclofen pump implant for the treatment of spasticity. Many complications are known to occur at a higher rate in this population, and some may be avoided with prior awareness of the preoperative pathophysiology of the patient with CP.

Neuroleptic malignant syndrome induced by lamotrigine

This case report describes a 54-year-old man with bipolar I disorder who was treated with aripiprazole (ARP) and lithium. The patient was admitted to our hospital because of aggravation of depressive symptoms, and treatment with lamotrigine (LTG) was initiated. Two weeks after admission, we discontinued administration of ARP after the appearance of a tremor. Three weeks after discontinuing ARP, the patient developed a high fever, rigidity of the arms, diarrhea, dysphagia, and diaphoresis. We suspected these symptoms were consistent with neuroleptic malignant syndrome and therefore removed the application of LTG. After 2 days, most of the patient's symptoms and blood results had improved, leading us to conclude that the LTG treatment had induced neuroleptic malignant syndrome. Thus, the purpose of this case report was to warn psychiatrists against therapy with LTG, as it may be conducive to neuroleptic malignant syndrome.

Surgical management of spasticity

Intractable and severe spasticity in childhood has the ability to impact on the quality of life, function and care of the child. Where medical and physical measures have proved insufficient, a surgical approach may be pursued. Irrespective of the underlying pathology, intrathecal baclofen will reduce spasticity in a controllable and reversible fashion, whereas selective dorsal rhizotomy is reserved for the management of bilateral cerebral palsy due to early birth. Owing to the potential for complications of intrathecal baclofen and the permanence of selective dorsal rhizotomy, careful selection and preparation are required to produce satisfactory results.

Intrathecal baclofen therapy: benefits and complications

BACKGROUND

Spasticity and dystonia in children with cerebral palsy has been treated with intrathecal baclofen therapy (ITB) at the Royal Children's Hospital, Melbourne, Australia (RCH) since 1999.

METHODS

The records of children having received or still receiving ITB during the period September 1999 until August 2005 were studied to evaluate complications and side effects. Parents answered a questionnaire focused on the health and functional impact in the children.

RESULTS

There were 18 first insertions of pumps, 6 removals, and 4 reinsertions. The longest treatment was 5 years and 11 months and was still ongoing. Seventeen complications occurred in 14 out of 18 children. Despite the high complication rate and the lack of significant functional improvement, 11 out of 12 parents agreed that ITB was beneficial.

CONCLUSION

ITB treatment at RCH over the years has resulted in some complications, mostly occurring shortly after pump insertion. For the majority of children there are substantial benefits.

Acute intrathecal baclofen withdrawal: a brief review of treatment options

BACKGROUND

Acute baclofen toxicity and withdrawal can present with a constellation of symptoms making differentiation between these two entities and other potential diagnoses challenging. Baclofen withdrawal is associated with numerous complications which may require neurocritical care expertise such as respiratory failure, refractory seizures, delirium, and blood pressure lability.

METHODS

Case report and literature review.

RESULTS

This case report discusses a case of intrathecal baclofen (ITB) withdrawal, focusing on the differential diagnosis for acute baclofen withdrawal and reviews the various options that exist to treat the symptoms of acute baclofen withdrawal such as benzodiazepines, propofol, skeletal muscle relaxants, and tizanidine.

CONCLUSIONS

Critical care practitioners should be prepared to treat this potentially devastating and often refractory complication of ITB therapy.

Rhabdomyolysis as a postoperative complication of multilevel soft-tissue surgery in a child with cerebral palsy

Rhabdomyolysis is a potentially life-threatening syndrome if unrecognized. The most common causes are trauma, excessive muscle activity, alcohol abuse, and toxic substances. Rhabdomyolysis as a postoperative complication in children with cerebral palsy who have received multilevel soft-tissue surgery has not been reported in the literature. The purposes of this study are to present the case of a 12-year-old boy with spastic quadriplegic cerebral palsy who developed rhabdomyolysis after soft-tissue release and to review the literature. The patient was treated with adequate sedation and hydration, and discharged in a stable condition 11 days after surgery. His serum creatine kinase level had returned to within the normal range by the 17th postoperative day. At the 6-month follow-up, there were no systemic sequelae. The prompt recognition of rhabdomyolysis depends on a high level of suspicion. Routine checks of urine color after surgery is mandatory. For patients with high muscle tone, monitoring of muscle enzymes is recommended. Adequate sedation, pain control and hydration may prevent the progression of this life-threatening condition.

Status dystonicus resembling the intrathecal baclofen withdrawal syndrome: a case report and review of the literature

Introduction

Status dystonicus is a rare but life-threatening disorder characterized by increasingly frequent and severe episodes of generalized dystonia that may occur in patients with primary or secondary dystonia. Painful and repetitive spasms interfere with respiration and may cause metabolic disturbances such as hyperpyrexia, dehydration, respiratory insufficiency, and acute renal failure secondary to rhabdomyolysis. Intrathecally administered baclofen, delivered by an implantable pump system, is widely used for the treatment of refractory spasticity. Abrupt cessation of intrathecal baclofen infusion has been associated with a severe withdrawal syndrome comprised of dystonia, autonomic dysfunction, hyperthermia, end-organ failure and sometimes death. The aetiology of this syndrome is not well understood. Status dystonicus describes the episodes of acute and life-threatening generalized dystonia, which occasionally manifest themselves in patients with dystonic syndromes.

Case presentation

We present the case of a nine-year-old Caucasian boy who experienced a severe episode of status dystonicus with no known cause and clinical features resembling those described in intrathecal baclofen withdrawal. Our patient subsequently underwent the placement of an intrathecal baclofen pump without incident.

Conclusion

The similarity between the clinical features of the case we present and those reported in connection to abrupt withdrawal of intrathecal baclofen is emphasized. Several drugs, although not intrathecal baclofen withdrawal, have previously been associated with status dystonicus. The similarity between the life-threatening dystonic episode experienced by our patient, and those reported in intrathecal baclofen withdrawal, highlights the possibility that, rather than representing a true physiological withdrawal syndrome, abrupt withdrawal of intrathecal baclofen may simply precipitate an episode of status dystonicus in susceptible individuals. The clinical similarities between the intrathecal baclofen withdrawal syndrome and status dystonicus have not previously been highlighted.

Consensus on the appropriate use of intrathecal baclofen (ITB) therapy in paediatric spasticity

Among features of motor disorders in children, spasticity is associated with considerable morbidity and problems in care, particularly in severely affected patients. Intrathecal baclofen (ITB) has been increasingly used as a relatively specific treatment modality for spasticity. To date, most of the evidence for its use in paediatric patients has come from retrospective and uncontrolled studies, although randomised, controlled trials of screening ITB and ITB therapy itself have recently been published. This consensus statement on the use of ITB in paediatric patients with spasticity was developed on the basis of currently available evidence, with the aim of providing information for clinicians, promoting an expert opinion and a consistent approach to the management of these patients and emphasising the need for further prospective, large-scale studies.

Neuroleptic malignant syndrome from central nervous system insult: 4 cases and a novel treatment strategy. Clinical article

Neuroleptic malignant syndrome (NMS) is a potentially life-threatening entity characterized by hyperthermia, autonomic deregulation, decreased mental status, increased muscle tone, and, frequently, by renal failure due to rhabdomyolysis. Classically, it follows administration of antipsychotic medication. The authors report on 4 patients (2 children and 2 adults) in whom NMS was diagnosed after a CNS insult. No patient was receiving antipsychotic medication. The patients' hospital and clinic charts, radiographic data, and follow-up telephone conversations were reviewed retrospectively. All 4 patients met diagnostic criteria for NMS. Three patients presented with shunt failure, and 1 patient had undergone a functional hemispherectomy 2 days earlier. One patient with shunt failure received the diagnosis retrospectively. An endoscopic third ventriculostomy alleviated his shunt failure and he remains free of NMS. The other 2 patients underwent treatment for shunt failure, but NMS remained. These 2 patients and the one who had undergone hemispherectomy underwent a trial of intrathecal baclofen, and the NMS resolved. Subsequently, an intrathecal baclofen infusion device was placed in all 3 patients, and the NMS resolved. The 2 patients in shunt failure had a lumbar intrathecal baclofen infusion device. The patient who had undergone hemispherectomy had an intracranial baclofen catheter. Neuroleptic malignant syndrome is a rare, life-threatening disorder that can occur without the administration of neuroleptic medications. Alleviation of any CNS insult is the first order of treatment. Some patients with persistent symptoms of NMS may benefit from intrathecal delivery of baclofen.

Intrathecal baclofen withdrawal resembling serotonin syndrome in an adolescent boy with cerebral palsy

Intrathecal baclofen (ITB) is increasingly being used to reduce spasticity among children with cerebral palsy, dystonia, and spinal cord injuries. However, complications such as withdrawal, which is a potentially life-threatening condition, can occur. Intrathecal baclofen withdrawal should be differentiated with autonomic dysreflexia, malignant hyperthermia, neuroleptic malignant syndrome, and serotonin syndrome. We report a case of ITB withdrawal secondary to low residual volume in the pump reservoir and resembling serotonin syndrome in an adolescent with cerebral palsy. He presented with agitation, diaphoresis, increasing spasticity, rigidity, jitteriness, hyperreflexia, clonus, tachycardia, hypertension, and rhabdomyolysis. Treatment consisted of emergent refilling of the pump, intravenous diazepam, and oral cyproheptadine. We also emphasize the importance of prompt recognition of ITB withdrawal among high-risk patients.

[Continuous infusion of baclofen and an antibiotic for treating meningitis related to refilling of an intrathecal infusion pump reservoir]

Baclofen via intrathecal infusion pump is a widely used treatment severe spasticity. Complications are rare and usually mild, though they can also be serious. The sudden discontinuation of intrathecal baclofen may have significant adverse effects. We report the case of a 59-year-old man with chronic spasticity and torsion dystonia who developed meningitis due to Staphylococcus epidermidis due to contamination of the intrathecal, infusion pump reservoir during refilling. It was decided to treat the patient by administering vancomycin through the pump, together with the baclofen. We believe that changing the intrathecal perfusion pump is not necessary as the first measure to take in these cases. Combined infusion of baclofen and an antibiotic through the pump makes it possible to maintain antispastic treatment, sterilize the pump reservoir and tubes, and effectively treat infections that develop during use of these systems.

Conduite à tenir devant une recrudescence de spasticité chez un patient porteur d'une pompe à baclofène

INTRODUCTION

The incidence of complications after baclofen pump implantation is relatively high. Diagnosis of these complications can be difficult. A diagnostic tree would be a useful tool in cases of suspected malfunctioning of the intrathecal bacolfen infusion system and would standardise the diagnostic procedure.

METHOD

From results in the literature and the experience of our department, we designed a diagnostic tree to aid in finding the cause of a recrudescence of spasticity in patients with implanted baclofen pumps.

RESULTS

The potential causes of recrudescence of spasticity are described and a diagnostic pathway is proposed.

DISCUSSION

The aim of a standardised hierarchical method of diagnosis of the cause of increased spasticity in patients with intrathecal baclofen pumps is to gain time in the diagnosis and treatment. Such diagnosis should improve patient care by permitting rapid restoration of an adequate level of baclofen infusion as well as decreasing the length of hospital stay and, as a consequence, the cost relating to malfunctioning pumps.

Delirium Associated With Baclofen Withdrawal: A Review of Common Presentations and Management Strategies

The authors reviewed 23 published cases of psychiatric symptoms in association with baclofen withdrawal. Delirium, and not other functional psychiatric conditions, arose secondarily from abrupt baclofen cessation. Vulnerability to baclofen-withdrawal delirium appeared to be greater in individuals who received chronic baclofen therapy. Baclofen-withdrawal delirium can be difficult to distinguish from delirium of other etiologies, and unrecognized and inadequately treated baclofen-withdrawal delirium is associated with significant morbidity and mortality. Complete resolution of delirium symptoms was possible with reinstatement of baclofen. The clinical management of patients experiencing baclofen-withdrawal delirium includes supportive interventions to reduce complications of delirium until symptoms resolve.

Intrathecal baclofen overdose followed by withdrawal: clinical and EEG features

Intrathecal baclofen therapy is increasingly used to alleviate medically intractable spasticity in children with cerebral palsy, spinal cord injuries, and generalized dystonia. Complications like overdose or withdrawal can occur and could be the result of pump malfunction (device-related) or refilling and programming mistakes (human errors). This report describes a case, with emphasis on electroencephalographic changes, of a 12-year old male on long-term intrathecal baclofen therapy who had sequential occurrence of both acute inadvertent baclofen overdose followed by withdrawal symptoms. During baclofen intoxication, electroencephalography documented periodic generalized epileptiform discharges, occasionally followed by intermittent electro-decremental responses on a background of diffuse delta slowing (1-2 Hz). During withdrawal, mild generalized slowing during wakefulness was observed along with the appearance of high-amplitude, sharply contoured delta activity resembling frontal intermittent rhythmic delta activity in sleep. To our knowledge, this temporal profile of electroencephalographic features during baclofen intoxication followed by withdrawal has not been described before in pediatric patients. It is important for treating physicians to recognize the evolution of this electroencephalographic pattern in order to avoid misinterpretation of diagnosis and prognosis.

Prolonged intrathecal baclofen withdrawal syndrome. Case report and discussion of current therapeutic management

The authors describe a patient who experienced a prolonged course of intrathecal baclofen withdrawal syndrome after removal of an implantable baclofen pump for treatment of pump infection and meningitis. The current literature outlines management options for the acute management of this syndrome. In this report the authors discuss the long-term presentation of this syndrome and suggest a treatment strategy for management of the syndrome. A 37-year-old man who presented with a baclofen pump infection and meningitis experienced acute onset of intrathecal baclofen withdrawal syndrome 12 hours after the pump had been surgically removed. The patient's symptoms evolved into a severe, treatment-refractory withdrawal syndrome lasting longer than 1 month. Oral baclofen replacement with adjunctive administration of parenteral gamma-aminobutyric acid agonists only served to stabilize the patient's critical condition throughout his hospital course. Replacement of the baclofen pump and restoration of intrathecal delivery of the medication was necessary to trigger the patient's dramatic recovery and complete reversal of the withdrawal syndrome within approximately 48 hours. These findings indicate that a more direct method of treating infected baclofen pumps than immediate surgical removal is necessary to prevent the onset of intrathecal baclofen withdrawal syndrome. Various options for preventing the onset of the syndrome while simultaneously treating the infection are discussed.

Pruritus after intrathecal baclofen withdrawal: A retrospective study

OBJECTIVES

To determine the frequency of pruritus after intrathecal baclofen (ITB) withdrawal and to study the pathophysiology of this symptom.

DESIGN

Retrospective cohort study.

SETTING

Rehabilitation department of a general hospital.

PARTICIPANTS

Patients (N=102) implanted with an ITB pump who had been followed up since 1988.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Incidence of pruritus after withdrawal. We studied the relation between pruritus and daily dose, concentration and mode of infusion of baclofen, and cause of the central nervous system lesion inducing spasticity.

RESULTS

Pruritus was observed in 10 of 23 cases of ITB withdrawal. It never occurred during the first 3 months after pump implantation. It seems likely that the segmental spinal action of baclofen is responsible for pruritus. There was no statistically significant difference between patients with ITB deprivation who did and did not experience pruritus in their daily infused dosage or in concentration and mode of infusion. Surprisingly, no pruritus was observed in patients with multiple sclerosis.

CONCLUSIONS

Pruritus is a frequent symptom after ITB withdrawal. Its occurrence is probably subsequent to chronic blocking of the liberation of substance P by baclofen at the spinal level. This symptom is a good clinical predictor of baclofen withdrawal, in contrast to an isolated increase of spasticity that may be due to drug tolerance or irritant factors. Pruritus requires investigation of a possible dysfunction of the infusion system.

Intrathecal baclofen withdrawal syndrome caused by low residual volume in the pump reservoir: A report of 2 cases

Intrathecal baclofen (ITB) is an effective treatment for spasticity caused by spinal or cerebral pathologies. Severe withdrawal symptoms can result, however, if ITB is abruptly withdrawn as a result of equipment malfunctions or human error. We describe 2 cases of severe ITB withdrawal syndrome. In the first case, the symptoms appeared 5 months after pump placement, when residual volume was 2.0 mL; in the second case, symptoms appeared 2 months after the replacement of a new pump, when residual volume was 0.9 mL. In both cases, there was no evidence of system malfunction or human error. The syndrome occurred from up to 72 hours before the scheduled refilling procedure, and the residual volume in the Medtronic SynchroMed EL pump reservoir was either at, or significantly lower than, the recommended 2 mL. These cases suggest that the SynchroMed EL pump reservoir should be refilled, to avoid potentially serious consequences, when the residual volume is not lower than 3 mL by programming the alarm to sound at a volume larger than the recommended 2 mL.

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.

Neuroleptic malignant syndrome: risk factors, pathophysiology, and treatment

Neuroleptic malignant syndrome (NMS) is associated with the administration of antipsychotic agents and other drugs such as l-dopa, antidepressants, and antihistaminic agents. Unexpected changes in mental status, new-onset catatonia, episodic tachycardia, tachypnea, hypertension, dysarthria, dysphagia, diaphoresis, sialorrhea, incontinence, low-grade temperature elevations, and rigidity should arouse suspicion. Several lines of evidence provide support for the involvement of dopamine. Most of the drugs implicated in NMS are D2 dopamine receptor antagonists. Central noradrenergic activity is also possibly related to the disorder, as sympathetic hyperactivity is associated with the active phase of NMS. Currently, the definitive role of GABA deficiency in NMS is yet to be established. Differential diagnosis should include malignant hyperthermia, lethal catatonia, lithium toxicity, serotonin syndrome, and heat stroke. A high degree of suspicion and the discontinuation of antipsychotic agents even if the diagnosis is not established are essential for the safety of the patient. Treatment of NMS should be individualized and be based empirically on the character, duration, and severity of the clinical signs and symptoms noted. The initial step in the treatment of NMS is the removal of the offending agent. Full-blown NMS is a serious condition and requires immediate supportive, nutritive, and electrolyte therapies. The administration of drugs that can improve NMS, such as IV dantrolene and/or oral bromocriptine, may also be taken into consideration, based on the severity and nature of the NMS.

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.

Drug-induced rhabdomyolysis

PURPOSE OF REVIEW

Drug-induced rhabdomyolysis is a common syndrome that is complex and potentially life threatening. This article reviews the pathophysiology, clinical presentations, and common compounds that cause drug-induced rhabdomyolysis.

RECENT FINDINGS

The list of drugs and inciting agents that cause rhabdomyolysis is quite extensive. Rhabdomyolysis is defined as skeletal muscle injury that leads to the lysis of muscle cells and the leakage of myocyte contents into the extracellular compartments. The presenting clinical features are myalgias, myoglobinuria, and an elevated serum creatine kinase. There have been several case reports in the literature involving some common pediatric drugs that are associated with rhabdomyolysis. Diphenhydramine, Ecstasy, and baclofen have recently been implicated as the etiology of drug-induced rhabdomyolysis in several pediatric patients. Alkalinization of the urine is a controversial treatment of drug-induced rhabdomyolysis and has proven to be beneficial in some patients.

SUMMARY

A high index of suspicion, early recognition, and adequate treatment will result in an excellent prognosis of drug-induced rhabdomyolysis.

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.