Acute onset rhythmic hiccup-like respirations secondary to oral baclofen toxicity

Systemic and intrathecal baclofen produce bladder antinociception in rats

BACKGROUND

Baclofen, a clinically available GABAB receptor agonist, produces non-opioid analgesia in multiple models of pain but has not been tested for effects on bladder nociception.

METHODS

A series of experiments examined the effects of systemic and spinally administered baclofen on bladder nociception in female anesthetized rats. Models of bladder nociception included those which employed neonatal and adult bladder inflammation to produce bladder hypersensitivity.

RESULTS

Cumulative intraperitoneal dosing (1-8 mg/kg IP) and cumulative intrathecal dosing (10-160 ng IT) of baclofen led to dose-dependent inhibition of visceromotor responses (VMRs) to urinary bladder distension (UBD) in all tested models. There were no differences in the magnitude of the analgesic effects of baclofen as a function of inflammation versus no inflammation treatments. Hemodynamic (pressor) responses to UBD were similarly inhibited by IT baclofen as well as UBD-evoked excitatory responses of spinal dorsal horn neurons. The GABAB receptor antagonist, CGP 35,348, antagonized the antinociceptive effects of IT baclofen on VMRs in all tested models but did not affect the magnitude of the VMRs by itself suggesting no tonic GABAB activity was present in this preparation. Tolerance to a seven day continuous IT infusion of baclofen was not observed.

CONCLUSIONS

These data provide support for a clinical trial of baclofen as a non-opioid treatment of human bladder pain.

Baclofen Toxicity Mimicking Brain Death: A Case Report of a Pediatric Patient

BACKGROUND

Baclofen is commonly used in both pediatric and adult patients to treat spasticity secondary to spinal cord and cerebral pathology. A broad range of symptoms and severity of baclofen toxicity have been described. However, to our knowledge, there are no reports to date of baclofen toxicity mimicking brain death in pediatric patients.

OBJECTIVE

We reviewed the presentation, clinical course, diagnostic studies including imaging and electroencephalography, and outcome of a patient with transient coma and loss of brainstem reflexes mimicking brain death secondary to baclofen toxicity.

METHODS

During a baclofen pump refill, a 12-year-old boy with cerebral palsy had inadvertent injection of 12,000 μg of baclofen into the pocket around his pump. Within an hour, he presented with acute altered mental status that rapidly progressed to a comatose state with absent brainstem reflexes.

RESULTS

After appropriate management, the patient returned to his neurological baseline by hospital day 3.

DISCUSSION

We reviewed the literature for varying presentations of baclofen toxicity and associated electroencephalography findings, mechanism of overdose, and different management options. In this case, the mechanism of baclofen toxicity was suspected to be secondary to extravasation from the pump pocket and subsequent systemic absorption.

CONCLUSIONS

Patients with baclofen toxicity may have a dramatic presentation and an initial examination mimicking brain death. Given its rarity, this clinical entity may not be readily recognized, and there is potential for misinterpretation of diagnosis and prognosis. It is important for physicians to be familiar with this clinical scenario to avoid false declaration of brain death.

Polysomnographic Analysis of a Pediatric Case of Baclofen-Induced Central Sleep Apnea

ABSTRACT

Respiratory disorders may follow brain injury and may also occur because of comorbidities and drug use, especially central depressants or muscle relaxants. Sleep can precipitate respiratory disorders, thus polysomnography can be a powerful diagnostic tool. By revealing breathing patterns that identify specific sleep disorders, polysomnography may unmask adverse pharmacological effects, for instance connecting central depressant drugs with central sleep apneas. We describe the case of a pediatric patient in rehabilitation from brain injury who developed a central sleep apnea following a baclofen dose increase within the therapeutic range, while assuming an under-dosed benzodiazepine. Polysomnography identified a typical respiration pattern, previously observed in adults treated with baclofen and other central depressants. Baclofen tapering resolved the central sleep apnea. Polysomnography, and this specific pattern, may be proposed as diagnostic tools in patients with high dose baclofen that can be used to prevent potential respiratory disorders in children.