Opioid overdose in a child: case report and discussion with emphasis on neurosurgical implications

Neuroimaging features of accidental fentanyl overdose in a toddler

The opioid epidemic has become a significant public health crisis worldwide. With the rise in popularity of fentanyl, opioid overdoses continue to rise at unprecedented rates. Unfortunately, young children have become collateral damage in the face of the opioid epidemic. Accidental exposures and ingestions are the leading cause of opioid overdose in this age group and can result in significant acute complications, long-term sequelae and even death. We present the case of a toddler with accidental fentanyl ingestion who experienced seizures and required intubation for respiratory distress. He was found to have notable diffusion restriction cerebellar changes on MRI and ultimately discharged with normal neurological function. Our case adds to the growing literature of the clinical presentation and neuroimaging features associated with opioid toxicity in young children.

A Case of Opiate-Induced Toxic Leukoencephalopathy in a Middle-Aged Woman

Toxic leukoencephalopathy is a disorder characterized by the alteration of myelin in white matter tracts secondary to exposure to neurotoxic substances. Here we describe a case of a middle-aged woman who presented to the emergency department with a history of bizarre behaviour, speech abnormalities and generalised muscle stiffness caused due to recent opioid overdose. Further investigations and extensive neurological tests, including magnetic resonance imaging (MRI) scan of the brain, demonstrated features consistent with toxic leukoencephalopathy (TLE). The patient was managed conservatively with the care of a multidisciplinary team involving a dietician, physiotherapist and speech and language therapist. She showed gradual and slow but significant recovery following a period of neurorehabilitation. The clinical presentation of TLE varies but MRI typically shows diffuse bi-lateral white matter lesions. History of neurotoxin exposure, presenting clinical signs and symptoms and radiological findings are significant in making the diagnosis. Early recognition is crucial and can help optimize patient's recovery and prevent severe complications.

Fatal fentanyl-associated cerebellitis in a young man

A 22-year-old man was brought in by EMS for coma and respiratory failure. The initial diagnosis was an opioid overdose but the patient did not respond to naloxone. A head CT revealed findings consistent with cerebellitis. The patient developed obstructive hydrocephalus and herniation. Despite neurosurgical and ICU care, the patient did not recover. Cerebellitis is a seldom-discussed complication of opioid use which may become more common as the opioid and fentanyl epidemic evolves.

Acute Cytotoxic Cerebellar Edema Subsequent to Fentanyl Patch Intoxication in an Infant

The opioid epidemic continues to have devastating consequences for children and families across the United States with rising prevalence of opioid use and abuse. Given the ease of access to these medications, accidental ingestion and overdose by children are becoming increasingly more common. The recognition of opioid-induced neurotoxicity and the associated life-threatening complication of acute cerebellar cytotoxic edema are crucial, as are the high morbidity and mortality without timely intervention. We discuss an infant with acute cytotoxic cerebellar edema following mucosal exposure to a transdermal fentanyl patch.

The molecular neurobiology and neuropathology of opioid use disorder

The number of people diagnosed with opioid use disorder has skyrocketed as a consequence of the opioid epidemic and the increased prescribing of opioid drugs for chronic pain relief. Opioid use disorder is characterized by loss of control of drug taking, continued drug use in the presence of adverse consequences, and repeated relapses to drug taking even after long periods of abstinence. Patients who suffer from opioid use disorder often present with cognitive deficits that are potentially secondary to structural brain abnormalities that vary according to the chemical composition of the abused opioid. This review details the neurobiological effects of oxycodone, morphine, heroin, methadone, and fentanyl on brain neurocircuitries by presenting the acute and chronic effects of these drugs on the human brain. In addition, we review results of neuroimaging in opioid use disorder patients and/or histological studies from brains of patients who had expired after acute intoxication following long-term use of these drugs. Moreover, we include relevant discussions of the neurobiological mechanisms involved in promoting abnormalities in the brains of opioid-exposed patients. Finally, we discuss how novel strategies could be used to provide pharmacological treatment against opioid use disorder.

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Brain abnormalities caused by opioid intoxication.

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Intoxication of opioids leads to defects in brain neurocircuitries.

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Insight into the molecular mechanisms associated with craving in heroin addicts.

Acute Cerebellitis and Atypical Posterior Reversible Encephalopathy Syndrome Associated with Methadone Intoxication

We report a case of a 9-year-old boy who presented with altered mental status and ataxia following 3 days of vomiting. Shortly after arrival to our emergency department, he declined and required intubation. The following day, he recovered and was successfully extubated. He was found to be positive for methadone on his urine drug screen. Brain imaging demonstrated a pattern of acute cerebellitis. Following extubation, the patient returned to his normal mental status; however, he began to have consistently elevated blood pressure and bradycardia and subsequent brain imaging showed supratentorial changes that were related to atypical posterior reversible encephalopathy syndrome. Through medical management including high-dose steroids and antihypertensive medications, the patient's blood pressure normalized, and he was eventually discharged home without further complications.

Cerebellar Hippocampal and Basal Nuclei Transient Edema with Restricted diffusion (CHANTER) Syndrome

Background

Abnormal restricted diffusion on magnetic resonance imaging is often associated with ischemic stroke or anoxic injury, but other conditions can present similarly. We present six cases of an unusual but consistent pattern of restricted diffusion in bilateral hippocampi and cerebellar cortices. This pattern of injury is distinct from typical imaging findings in ischemic, anoxic, or toxic injury, suggesting it may represent an under-recognized clinicoradiographic syndrome. Despite initial presentation with stupor or coma in the context of obstructive hydrocephalus, patients may have acceptable outcomes if offered early intervention.

Methods

We identified an ad hoc series of patients at our two institutions between years 2014 and 2017 who presented to the neurocritical care unit with severe, otherwise unexplained cerebellar edema and retrospectively identified several commonalities in history, presentation, and imaging.

Results

Between two institutions, we identified six patients—ages 33–59 years, four male—with similar presentations of decreased level of consciousness in the context of intoxicant exposure, with acute cytotoxic edema of the cerebellar cortex, hippocampi, and aspects of the basal nuclei. All patients presented with severe cerebellar edema which led to obstructive hydrocephalus requiring aggressive medical and/or surgical management. The five patients who survived to discharge demonstrated variable degrees of physical and memory impairment on discharge and at follow-up.

Conclusions

We present findings of a potentially novel syndrome involving a distinct pattern of cerebellar and hippocampal restricted diffusion, with imaging and clinical characteristics distinct from ischemic stroke, hypoxic injury, and known toxidromes and leukoencephalopathies. Given the potential for favorable outcome despite early obstructive hydrocephalus, early identification and treatment of this syndrome are critical.

Opioid-induced toxic leukoencephalopathy: A case report and review of the literature

Importance

Reports of toxic leukoencephalopathy (TLE) due to opioids have been extensively documented within the adult literature. There is a paucity of literature with respect to the incidence, complications, and outcomes of TLE in the pediatric population.

Objective

To describe a rare complication of opioid ingestion in the pediatric population and serve as the first large review of published cases of opioid-induced leukoencephalopathy. Thirteen case reports with varying treatments are herein reviewed in addition to our own case. The range of treatment modalities, morbidity and mortality are broad and outcomes secondary to supportive care versus neurosurgical intervention is explored.

Evidence review

All cases of pediatric opioid-induced toxic leukoencephalopathy published on pubmed and google scholar were included in this review.

Findings

We report the case of a 4-year old male surgically treated for acute oxycodone-induced TLE who initially presented with Glascow Coma Scale of 4 and a comatose state for weeks. Over the next several months he recovered with spasticity of all extremities, oral aversion, substantial vision loss, and the ability to speak in short sentences. In addition, we found thirteen other reported cases of opioid-induced leukoencephalopathy reported in the literature. The treatment approaches described range from supportive care alone, to invasive neurosurgical interventions including placement of extraventricular drains, removal of hemorrhagic tissue, and craniectomy. The outcomes of patients with opioid-induced leukoencephalopathy is also variable. Reports demonstrate a range of outcomes that include patients who died to those with no residual neurologic deficits.

Conclusions

This review of reported pediatric cases of opioid-induced leukoencephalopathy highlights the importance of early neurosurgical intervention for prevention of devastating outcomes.

Malignant cerebellar edema in three-year-old girl following accidental opioid ingestion and fentanyl administration

A three-year-old girl was found altered with an unknown timeline. Gas chromatography mass spectrometry was positive for hydromorphone, dihydrocodeine, and hydrocodone. Initial computed tomography and magnetic resonance imaging suggested a malignant cerebellar edema not confined to a vascular distribution. She received fentanyl boluses on hospital days 0 and 1 before receiving a continuous infusion on day 1. On day 3, she had an episode of acute hypertension and bradycardia. Emergent computed tomography showed an evolving hydrocephalus and similar diffuse edema throughout both cerebellar hemispheres. External ventricular drain was placed to relieve the increased intracranial pressure. Following drain placement and fentanyl discontinuation, the patient recovered, though not without fine- and gross-motor deficits at the four-month follow-up. Our case adds to a handful of case reports of opioid toxicity in pediatric patients that present as toxic leukoencephalopathy. Though the mechanism is poorly understood, it has been suggested to be a consequence of the neurotoxic effects of the drug, which has particular affinity for µ opioid receptors-the primary opioid receptor found in the cerebellum. Clinicians would do well to recognize that this syndrome is primarily caused by direct toxicity rather than ischemia. This case adds insight by suggesting that lipophilic opioid analgesics may worsen this neurotoxicity. When intervening with mechanical ventilation, clinicians should consider avoiding lipophilic opioid drugs for analgesia until the pathogenesis of cerebellar edema is better understood.

Acute Cerebellitis in Children: A Variable Clinical Entity

Acute cerebellar ataxia is the most common cause of acute ataxia in children and it usually runs a self-limiting and ultimately benign clinical course. A small proportion of children have evidence of inflammatory swelling in the cerebellum. Many of these children suffer more severe and potentially life-threatening forms of cerebellar ataxia and may need more intensive treatments including urgent neurosurgical treatments. This more severe form of acute cerebellar ataxia is often termed acute cerebellitis. Many children with acute cerebellitis have long-term neurological sequela and evidence of structural cerebellar changes on follow-up imaging. Several patterns of cerebellar inflammation have been described. The authors describe the variabilities in the clinical and radiological patterns of disease in the cases that have been described in the literature.

Toxic-Metabolic Neurologic Disorders in Children: A Neuroimaging Review

There are multiple causes of neurotoxicity in children including medications, extrinsic toxins and insults, illicit drugs, built up of toxic metabolites due to genetic or acquired disorders, and metabolic abnormalities. The review is centered on causes of neurotoxicity affecting the pediatric brain and producing typical and easily recognized imaging manifestations. Early identification of common and less common imaging findings may point toward the correct direction, and may facilitate early diagnosis and institution of appropriate treatment to reverse or at least limit the injury to the developing brain. Two common imaging patterns of neurotoxicity in children are the posterior reversible encephalopathy syndrome and acute toxic leukoencephalopathy that are usually related to chemotherapy and immunosuppression for common pediatric malignancies. Another well-described imaging pattern of injury in children involves reversible splenial lesions with or without associated white matter abnormalities. Multiple additional extrinsic causes of neurotoxicity are presented including radiation and chemoradiation, various medications and treatment regimens, poisoning, illicit drug use or accidental exposure, and the respective characteristic neuroimaging findings are highlighted. Intrinsic neurotoxicity may occur in the setting of inborn errors of metabolism or acquired progressive organ failure leading to build up of toxic metabolites. Additional intrinsic causes of neurotoxicity include metabolic derangements and characteristic imaging findings in all instances are reviewed. The goal of the article is to enhance familiarity of neurologists and neuroradiologists with the imaging appearance of common and less common toxic insults to the pediatric brain.

Malignant Cerebellar Edema Subsequent to Accidental Prescription Opioid Intoxication in Children

We present two recent cases of toddlers who developed malignant cerebellar edema subsequent to accidental ingestion of prescription opioids. Both children presented acute neurological decline, hydrocephalus, and tonsillar herniation requiring emergent ventricular drain placement, suboccipital craniectomy, and partial cerebellectomy. Together with several other reports, these cases suggest the existence of an uncommon yet severe syndrome of acute opioid-induced malignant cerebellar edema. We hypothesize that the condition results from a combination of primary opioid receptor-mediated changes in neuronal metabolism that are exacerbated by secondary hypoxic insult. If recognized promptly, this syndrome can be treated with emergent neurosurgical intervention with good clinical outcomes. These cases also illustrate the unintended consequences and innocent victims of the spiraling prescription opioid epidemic, which will likely increase in prevalence. Recognition of this syndrome by clinicians is thus critical.