Reversible coma in children after improper baclofen pump insertion

Potentially Life-Threatening Interaction between Opioids and Intrathecal Baclofen in Individuals with a Childhood-Onset Neurological Disorder: A Case Series and Review of the Literature

BACKGROUND

 Spasticity and dystonia are movement impairments that can occur in childhood-onset neurological disorders. Severely affected individuals can be treated with intrathecal baclofen (ITB). Concomitant use of ITB and opioids has been associated with central nervous system (CNS) depression. This study aims to describe the clinical management of this interaction, based on a case series and review of literature.

METHODS

 Four individuals with childhood-onset CNS disorders (age 8-24) and CNS-depressant overdose symptoms after the concomitant use of ITB and opioids are described. The Drug Interaction Probability Scale (DIPS) was calculated to assess the cause-relationship (doubtful <2, possible 2-4, probable 5-8, and highly probable >8) of the potential drug-drug interaction. A literature review of similar previously reported cases and the possible pharmacological mechanisms of opioid-baclofen interaction is provided.

RESULTS

 After ITB and opioid co-administration, three out of four patients had decreased consciousness, and three developed respiratory depression. DIPS scores indicated a possible cause-relationship in one patient (DIPS: 4) and a probable cause-relationship in the others (DIPS: 6, 6, and 8). Discontinuation or adjusting ITB or opioid dosages resulted in clinical recovery. All patients recovered completely. In the literature, two articles describing nine unique cases were found.

CONCLUSION

 Although the opioid-ITB interaction is incompletely understood, concomitant use may enhance the risk of symptoms of CNS-depressant overdose, which are potentially life-threatening. If concomitant use is desirable, we strongly recommend to closely monitor these patients to detect interaction symptoms early. Awareness and monitoring of the potential opioid-ITB interaction is essential to reduce the risk of severe complications.

The use of opioids in children receiving intrathecal baclofen therapy

PURPOSE

We hypothesized that children on chronic intrathecal baclofen therapy (ITB) may require less analgesics for postoperative pain control and are at higher risk of developing opioid-induced respiratory depression postoperatively. The aims of this study are to review children on chronic intrathecal baclofen therapy receiving opioids after major surgery and to determine the incidence complications in this population.

METHOD

We conducted a retrospective cohort study comparing 13 children on ITB, who underwent posterior spinal fusion surgery, to 17 children with spina bifida that received the same surgery.

RESULTS

On postoperative day 0 (POD 0), four children (40%) had respiratory depression in the baclofen group compared to none in the control group. Desaturation was significantly more frequent in children in the ITB group compared to those of the control group on POD 0; oversedation was recorded in 8 (80%) children in the baclofen group vs. 3 (17.6%) in the control group. Desaturation, respiratory depression, and oversedation were significantly more frequent on POD 0 in children in the baclofen group compared with children in the control group.

CONCLUSIONS

The findings of the current study suggest that children on chronic intrathecal baclofen therapy require lesser amounts of opioids for postoperative pain control and are at a greater risk of developing postoperative respiratory depression and excessive sedation compared to patients without baclofen therapy.

Intrathecal baclofen therapy in children with acquired brain injuries after drowning: A case series

Objective: To investigate clinical efficacy as well as the incidence and extent of complications regarding intrathecal baclofen (ITB) therapy in children.

METHODS

This is a retrospective medical chart review of three paediatric patients with acquired brain injuries (ABI) resulting from drowning who underwent ITB pump implantation for treatment of severe spasticity.

RESULTS

Compared to the pre-operative state, ITB therapy reduced spasticity with a corresponding decrease of modified Ashworth scale in upper (3.2 ± 1.4 to 1.3 ± 0.6) and lower extremities (3.5 ± 0.9 to 2.0 ± 1.0). Overall, six complications, five device-related and one accidental, were found in two out of three patients.

CONCLUSION

Intrathecal baclofen is an effective therapy option for paediatric patients with ABI after drowning to significantly reduce spasticity of upper and lower extremities. A word of caution must be addressed to the incidence and extent of complications related to ITB therapy.

Intrathecal administration of GABA agonists in the vegetative state

Gamma aminobutyric acid (GABA) is an inhibitor neurotransmitter that plays many important roles in the central nervous system. Because the half-life time of GABA is very short in vivo, GABA itself is not used for clinical practice. An analogue of GABA, baclofen, is an agonist of GABA-B receptor, and has very strong antispastic effect by acting to the posterior horn of the spinal cord. However, baclofen poorly crosses through the blood brain barrier, and the antispastic effect is modest when administered orally. Therefore, direct continuous infusion of small doses of baclofen into the cerebrospinal fluid (intrathecal baclofen therapy, ITB) has become an established treatment for control of otherwise intractable severe spasticity. Spasticity is clinically defined as hypertonic state of the muscles with increased tendon reflexes, muscles spasm, spasm pain, abnormal posture, and limitation of involuntary movements. Spasticity is a common symptom after damage mainly to the pyramidal tract system in the brain or the spinal cord. Such damage is caused by traumatic brain injury, stroke, spinal cord injury, multiple sclerosis, and so on. Patients in persistent vegetative state (PVS) usually have diffuse and widespread damage to the brain, spasticity is generally seen in such patients. Control of spasticity may become important in the management of PVS patients in terms of nursing care, pain relief, and hygiene, and ITB may be indicated. Among PVS patients who had ITB to control spasticity, sporadic cases of dramatic recovery from PVS after ITB have been reported worldwide. The mechanism of such recovery of consciousness is poorly understood, and it may simply be a coincidence. On the other hand, electrical spinal cord stimulation (SCS) has been tried for many years in many patients in PVS, and some positive effects on recovery of consciousness have been reported. SCS is usually indicated for control of neuropathic pain, but it has also antispastic effect. The mechanism of SCS on pain is known to be mediated through the spinal GABA neuronal system. Thus, ITB and SCS have a common background, spinal GABA neuronal mechanism. The effect of GABA agonists on recovery of consciousness is not yet established, but review of such case studies becomes a clue to solve problems in PVS, and there may be hidden serendipity.

[Transition from childhood to adulthood and management of spasticity]

The authors report specific concerns on the transition to adulthood in cerebral palsy patients, with particular attention devoted to spasticity treatment follow-up.

Magnetic resonance spectroscopy and electroencephalography in baclofen coma

This report describes a 14-year-old female who presented with coma and seizures. Continuous electroencephalographic monitoring revealed suppression and semiperiodic sharp waves. Magnetic resonance spectroscopy performed 1 day after admission suggested a good outcome despite her clinical examination and electroencephalogram. She was subsequently found to have elevated serum baclofen levels after an intentional overdose. At the time of her discharge from the pediatric intensive care unit, she manifested no neurologic deficits, and on telephone follow-up 2 years after the ingestion the patient had no complaints of any cognitive problems or neurologic dysfunction.