Lesson of the month: Oxycodone-induced leukoencephalopathy: a rare diagnosis

Strong opioids-induced cardiac, neurologic, and respiratory disorders: a real-world study from 2004 to 2023 based on FAERS

Opioids are mainly used as adjuncts to the induction and maintenance of general anesthesia, postoperative analgesia, and treating moderate to severe cancer pain and chronic pain. However, the hazards of these drugs to various organ organs still need to be further explored. This study used the US FDA Adverse Event Reporting System (FAERS) database to determine whether commonly receiving opioids was higher than the baseline risk for all other medications. FAERS was asked about adverse events (AEs) for the opioids "morphine," "fentanyl," "oxycodone," "hydromorphone," "sufentanil," and "remifentanil" from the first quarter of 2004 (2004Q1) through the second quarter of 2023 (2023Q2). Disproportionality signaling analysis was performed by calculating reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and Empirical Bayesian Geometric Mean (EBGM). AEs with system organ classes (SOCs) of "cardiac disease," "neurologic disease," and "respiratory, thoracic, and mediastinal disease" were then screened. The statistical analysis included 12,819,518 reports in the FAERS database from 2004Q1 to 2023Q2, of which 236,619 AEs were reported as "primary suspect" for the six drugs mentioned above, which were selected as "cardiac disorders," "nervous system disorders," and "respiratory, thoracic and mediastinal disorders." Some AEs identified in this study are consistent with the drug labeling, such as bradycardia, respiratory depression, and somnolence. In addition, some unexpected and significant acute adverse drug reactions (ADRs), such as toxic leukoencephalopathy and coma, may occur. This study identified potential new and unexpected ADRs for opioids, providing valuable evidence for safety studies of opioids.

Toxic leukoencephalopathy versus delayed post-hypoxic leukoencephalopathy after oral morphine sulphate overdose

Toxic leukoencephalopathy (TLE) is a rare pathology caused by various substances including opioids (notably heroin), immunosuppressants, chemotherapy agents, cocaine, alcohol and carbon monoxide. However, although heroin is metabolised by the body into morphine, there is a striking paucity in cases of primary oral morphine-induced TLE, especially in the adult population. We present the case of a man in his 40s admitted to hospital in respiratory depression with a Glasgow Coma Scale (GCS) score of 6 after taking an overdose of oral morphine sulphate. Following a complete recovery to baseline, he was then readmitted with an acute deterioration in his neurobehavioural condition. Initial investigations returned normal but MRI showed changes characteristic for TLE.In cases of opioid toxicity such as ours, TLE is difficult to differentiate from delayed post-hypoxic leukoencephalopathy, due to their similar clinical presentation, disease progression and radiological manifestation. We explore how clinicians can approach this diagnostic uncertainty.

Toxic Leukoencephalopathy After "Chasing the Dragon" With a Non-Heroin Opioid

In the United States, the rate of opioid use increases each year. With this, users are engaging in more non-traditional methods of usage. "Chasing the dragon" is a term used to describe opioid inhalation, where the user heats the opioid and then inhales the smoke. While this method of usage is typically associated with a quicker high and fewer adverse effects, it can also lead to toxic leukoencephalopathy (TLE). TLE is defined as a structural alteration of the brain's white matter due to toxic exposure, such as heroin. A 57-year-old woman with a history of polysubstance abuse was admitted to the hospital after weeks of erratic behavior. At presentation, her urine drug screen was found to be positive for oxycodone (which was prescribed to her) and fentanyl. A brain MRI was eventually done, which showed a periventricular leukoencephalopathy characteristic of opioid inhalation. Traditionally, opioid-related TLE is due to heroin, and patients are found to have very dramatic motor issues. As this patient did not report a history of heroin use and did not present with significant motor deficits, this report highlights the need to maintain a level of suspicion for TLE. As levels of opioid use continue to rise, it is likely that many presentations like that of the patient outlined in this report will be seen.

Substance Use and the Nervous System

OBJECTIVE

This article informs and updates the practicing neurologist on the current landscape of known neurologic injuries linked to the use of illicit drugs, focusing on emerging agents.

LATEST DEVELOPMENTS

Synthetic opioids such as fentanyl and similar derivatives have exploded in prevalence, becoming the leading cause of overdose fatalities. The higher potency of synthetic opioids compared with semisynthetic and nonsynthetic opiates poses an increased risk for unintentional overdose when found as an adulterant in other illicit drug supplies such as heroin. Conversely, misinformation about the risk of symptomatic exposure to fentanyl through casual contact with the skin and ambient air has led to misdirected fear and stigma that threatens to impede valid harm-reduction measures for fentanyl users at risk of actual overdose. Finally, during the COVID-19 pandemic, overdose rates and deaths continued to climb, especially among those who use opioids and methamphetamine.

ESSENTIAL POINTS

A variety of potential neurologic effects and injuries can occur with illicit drug use owing to the diverse properties and mechanisms of action of the various classes. Many high-risk agents are not detected on standard drug screens, including so-called designer drugs, and the practicing neurologist is best served by recognizing the clinical features of the traditional toxidrome and other potential idiosyncratic effects of various illicit agents.

Opioid use disorder and the brain: a clinical perspective

Opioid use disorder (OUD) has gained increasing publicity and interest during recent years, with many countries describing problems of epidemic proportions with regard to opioid use and deaths related to opioids. While opioids are not themselves acutely neurotoxic, the chronic relapsing and remitting nature of this disorder means that individuals are often exposed to exogenous opioids for lengthy periods of time (either illicit or prescribed as treatment). We are increasingly characterizing the effect of such long-term opioid exposure on the brain. This narrative review aims to summarize the literature regarding OUD and the brain from a clinical perspective. Alterations of brain structure and function are discussed, as well as neurological and psychiatric disorders in OUD. Finally, we review current and new directions for assessment and treatment.

Apoptotic inducement of neuronal cells by codeine: possible role of disrupted redox state and caspase 3 signaling

Background

Codeine, a common drug of abuse, has been reported to induce organ damage; however, there are scanty available data on the effects of codeine on the brain.

Objective

Thus, we tested the hypothesis that redox dysregulation and inflammation of the brain induced by codeine exposure is 8-OHdG and/or caspase 3-dependent.

Methods

New Zealand White rabbits (Oryctolagus cuniculus) received vehicle (control; n = 7), low-dose codeine (4 mg/kg/day p.o; n = 6), or high-dose codeine (10 mg/kg/day p.o; n = 6) for six weeks. Body weight was checked before and after the study.

Results

Findings showed that codeine exposure resulted in redox dysregulation (evident by elevated MDA and H₂O₂ accompanied by reduced enzymatic antioxidant activities), elevated MPO activity, and distorted cytoarchitecture of the brain tissue. The observed codeine-induced redox imbalance and brain inflammation was accompanied by depletion of neuronal and purkinje cells, reduced AchE activity, and elevated 8-OHdG levels and caspase 3 activity.

Conclusions

The current study demonstrates that chronic codeine use induces oxido-inflammatory response and apoptosis of the brain tissue that is associated with neuronal and purkinje cells injury, and impaired AchE activity through 8-OHdG and/or caspase 3-dependent pathway.

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Codeine led to redox dysregulation and inflammation of the brain.

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This was accompanied by distorted cytoarchitecture of the brain.

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Codeine also caused depletion of neuronal and purkinje cells with reduced acetylcholinesterase activity.

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Codeine-induced brain injury was mediated by upregulation of 8-OHdG/caspase 3 signaling.

Bilateral cerebellar hemorrhagic infarcts as an early presentation following opioid-induced toxic encephalopathy in an adult patient

In the midst of the national opioid crisis, it is necessary for emergency physicians and radiologists to be familiar with presentations of opioid-related complications. We describe a case report of a 51-year-old female who developed bilateral cerebellar hemorrhages following opioid and benzodiazepine overdose. Malignant cerebellar edema is a rare but recognized complication following opiate overdose in children or chronic heroin toxicity. However, acute cerebellar involvement is rarely reported in adults. We feel that clinicians and radiologists should keep in mind the possibility of opioid toxic encephalopathy in their differential for adults with acute bilateral cerebellar infarcts and/or hemorrhages.