Toxic leukoencephalopathy after intravenous heroin injection: a case with clinical and radiological reversibility

Partial Recovery in Toxic Leukoencephalopathy: Is It Really a Slow Improvement or a Warning Sign?

A 55-year-old African American man who was found down by a friend nine hours after being last seen at the same place was brought to the emergency department (ED) with encephalopathy, lactic acidosis, rhabdomyolysis, elevated troponin, acute kidney injury (AKI), and transaminitis. His urine drug screen (UDS) was positive for cocaine. Intravenous (IV) Narcan was given with minimal improvement in mental status. A computed tomography (CT) scan of the head and a CT scan of the cervical spine in the ED showed no acute findings. Due to hypoxia, the patient was eventually intubated. The patient also required a fasciotomy and eventually hyperbaric oxygen (HBO) therapy due to the left lower extremity wound. He was transferred to our facility for further care. Due to incomplete cognitive recovery, as the patient was oriented to self only, further neurological workup, including magnetic resonance imaging (MRI) of the brain, was obtained, which showed bilateral symmetric T2 FLAIR (Fluid attenuated inversion recovery) hyperintensity in the globus pallidus. The patient had slow and gradual deterioration with worsening encephalopathy, akinetic mutism, parkinsonian features, and seizures, which prompted further evaluation from neurology. The patient eventually underwent extensive workup, including a continuous video electroencephalogram (cvEEG), repeat MRI brain with and without contrast, lumbar puncture for cerebrospinal fluid (CSF) analysis, MRI brain with diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS). The patient was treated with multivitamin therapy and coenzyme Q10, but there was no significant benefit. We report a case of cocaine-induced leukoencephalopathy with findings like 'chasing the dragon encephalopathy' with a possible component of delayed post-hypoxic injury with underlying neuroinflammation.

Prognosis in substance abuse-related acute toxic leukoencephalopathy: A scoping review

OBJECTIVES

Abuse of opiates, cocaine, and lipophilic inhalants (e.g., toluene) can damage brain myelin and cause acute toxic leukoencephalopathy (TL), but little is known about recovery or prognosis in this condition. In light of the ongoing opiate epidemic in the United States, it is important to understand the natural history of patients who have acute neurological complications from illicit drug exposure. Our aim was to conduct a scoping review of the literature regarding prognosis in described cases of substance abuse-related TL.

METHODS

A strategic search of PubMed, Ovid, Cumulative Index to Nursing, and Allied Health Literature (CINAHL) databases yielded adult cases of acute TL from opiates, cocaine, or inhalants. Cases and case series were eligible for inclusion if they described acute leukoencephalopathy with a clear temporal association with opiate, cocaine, or inhalant abuse. Inclusion was contingent on availability of clinical descriptions until death or ≥ 4 weeks follow-up with neuroimaging consistent with TL.

RESULTS

Among 52 cases from 14 articles, 21 (40.4%) individuals died with mean time to death of 28.2 days; with mean follow-up of 12.8 months, 10 (19.2%) survived with no recovery, 17 (32.7%) had partial recovery, and 4 (7.7%) individuals had full recovery.

CONCLUSION

Substance abuse-related acute TL often has a poor prognosis, but partial or even full recovery is possible in a subgroup of individuals over months to years.

Toxic Spongiform Leukoencephalopathy After Intravenous Heroin Abuse: Unusual But Important Differential Diagnosis of Acute Impairment of Consciousness

Abuse of heroin vapour inhalation known as "chasing the dragon" is associated with toxic spongiform leukoencephalopathy. However, similar clinical and imaging findings may occur also after intravenous heroin abuse. We report on a 32-year-old male suffering from extensive toxic spongiform leukoencephalopathy after intravenous heroin abuse resulting in acute impairment of consciousness and a global state of confusion. MRI disclosed broad and nearly symmetrical diffusion restriction of the supratentorial white matter indicating cytotoxic oedema. In an emergency setting, differential diagnosis of acute impairment of consciousness and broad symmetrical white matter lesions in neuroimaging should also include toxic leukoencephalopathy due to intravenous heroin application.

Neurocognitive impairments and brain abnormalities resulting from opioid-related overdoses: A systematic review

BACKGROUND

Non-fatal opioid-related overdoses have increased significantly over the past two decades and there have been increasing reports of brain injuries and/or neurocognitive impairments following overdose events. Limited preclinical research suggests that opioid overdoses may cause brain injury; however, little is known about such injuries in humans. The purpose this systematic review is to summarize existing studies on neurocognitive impairments and/or brain abnormalities associated with an opioid-related overdose in humans.

METHODS

PubMed, Web of Science, Ovid MEDLINE and PsyINFO were searched, without year restrictions, and identified 3099 articles. An additional 24 articles were identified by reviewing references. Articles were included if they were published in English, reported study findings in humans, included individuals 18 years of age or older, and reported an objective measure of neurocognitive impairments and/or brain abnormalities resulting from an opioid-related overdose. Six domains of bias (selection, performance, attrition, detection (two dimensions) and reporting were evaluated and themes were summarized.

RESULTS

Seventy-nine journal articles, published between 1973-2020, were included in the review. More than half of the articles were case reports (n = 44) and there were 11 cohort studies, 18 case series, and 6 case-control studies. All of the studies were categorized as at-risk of bias, few controlled for confounding factors, and methodological differences made direct comparisons difficult. Less than half of the studies reported toxicology results confirming an opioid-related overdose; 64.6 % reported brain MRI results and 27.8 % reported results of neuropsychological testing. Only two studies had within subject comparative data to document changes in the brain possibly associated with an overdose. Despite these limitations, existing publications suggest that brain injuries and neurocognitive impairments are associated with opioid overdose. Additional research is needed to establish the incidence of overdose-related brain injuries and the potential impact on functioning, as well as engagement in treatment of substance use disorders.

CONCLUSIONS

Respiratory depression is a defining characteristic of opioid overdose and prolonged cerebral hypoxia may cause brain injuries and/or neurocognitive impairments. The onset, characteristics, and duration of such injuries is variable and additional research is needed to understand their clinical implications.

Toxic Leukoencephalopathy due to Inhalational Heroin Abuse

Heroin-induced spongiform leukoencephalopathy (HSLE) is a rare condition that is strongly associated with heroin vapor inhalation which has become a popular method among heroin addicts because it poses a less immediate danger to the user and makes the drug much easier to use. We present a case of a 22-year-old male who presented with dysarthria and cerebellar symptoms starting, after 3 months of heroin inhalation. Diagnosis was confirmed to be HSLE after extensive diagnostic testing. HSLE is a rare complication of which the pathogenesis is poorly understood. Clinical history and characteristic findings on magnetic resonance imaging (diffuse, symmetric T2-hyperintensity, and diffusion restriction in frontal, parietal, occipital lobs, basal ganglia, and superior cerebellum) are diagnostic; however, care should be taken to exclude other etiologies. Treatment is primarily supportive; however, there is anecdotal evidence that coenzyme Q10 may be of benefit. The growing number of victims of the opioid crisis requires that physicians be aware of and counsel patients on the devastating neurological complications that can occur with abuse of these drugs.

Neuroprotection or Neurotoxicity of Illicit Drugs on Parkinson's Disease

Parkinson's Disease (PD) is currently the most rapid growing neurodegenerative disease and over the past generation, its global burden has more than doubled. The onset of PD can arise due to environmental, sporadic or genetic factors. Nevertheless, most PD cases have an unknown etiology. Chemicals, such as the anthropogenic pollutant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amphetamine-type stimulants, have been associated with the onset of PD. Conversely, cannabinoids have been associated with the treatment of the symptoms'. PD and medical cannabis is currently under the spotlight, and research to find its benefits on PD is on-going worldwide. However, the described clinical applications and safety of pharmacotherapy with cannabis products are yet to be fully supported by scientific evidence. Furthermore, the novel psychoactive substances are currently a popular alternative to classical drugs of abuse, representing an unknown health hazard for young adults who may develop PD later in their lifetime. This review addresses the neurotoxic and neuroprotective impact of illicit substance consumption in PD, presenting clinical evidence and molecular and cellular mechanisms of this association. This research area is utterly important for contemporary society since illicit drugs' legalization is under discussion which may have consequences both for the onset of PD and for the treatment of its symptoms.

Different routes of heroin intake cause various heroin-induced leukoencephalopathies

OBJECTIVE

Toxic leukoencephalopathy is a rare but critical neurological disorder in heroin abusers. Our aim is to compare the clinical manifestations, brain MRIs and prognoses of heroin-induced leukoencephalopathy by different intake routes.

METHODS

We present two patients with toxic leukoencephalopathy caused by intravenous (IV) injection of heroin and 48 additional cases from systematic reviews of the literature published between 1994 and 2018.

RESULTS

Among the 50 heroin abusers who developed leukoencephalopathy, inhalation was the most popular route (60%), followed by IV injection (30%) and snorting (10%). Mental changes, mutism and urine/fecal incontinence were the major symptoms in patients who IV injected heroin, while cerebellar ataxia and dysarthria were more common among those who inhaled heroin. Delayed-onset encephalopathy uniquely occurred in those who IV injected heroin, whereas progressive encephalopathy was more commonly observed in those who inhaled heroin. Clinical improvement was observed in 60% of patients, the overall mortality rate was 12%, and higher mortality was observed in patients who used the inhalation route (16.7%). The hallmarks on the MRIs of those who inhaled heroin were posterior to anterior involvement of the cerebral white matter and lesions in the posterior limbs of the internal capsules, cerebellum and brainstem. In contrast, those who IV injected heroin had more frequent lesions in the subcortical U fibers and the genu of the internal capsules.

CONCLUSION

These data could help physicians make an early diagnosis and predict prognosis and suggest that prompt antioxidative or symptomatic treatments might reduce the long-term consequences and mortality of heroin-induced leukoencephalopathy.

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.

Chronic oxycodone induces axonal degeneration in rat brain

BACKGROUND

Chronic opioid therapy for non-malignant pain conditions has significantly increased over the last 15 years. Recently, the correlation between opioid analgesics and alternations in brain structure, such as leukoencephalopathy, axon demyelination, and white matter lesions, has been demonstrated in patients with a history of long-term use of prescription opioids. The exact mechanisms underlying the neurotoxic effect of opioids on the central nervous system are still not fully understood. We investigated the effect of chronic opioids using an animal model in which female rats were orally gavaged with 15 mg/kg of oxycodone every 24 h for 30 days. In addition we tested oxycodone, morphine and DAMGO in breast adenocarcinoma MCF7 cells, which are known to express the μ-opioid receptor.

RESULTS

We observed several changes in the white matter of animals treated with oxycodone: deformation of axonal tracks, reduction in size of axonal fascicles, loss of myelin basic protein and accumulation of amyloid precursor protein beta (β-APP), suggesting axonal damages by chronic oxycodone. Moreover, we demonstrated activation of pro-apoptotic machinery amid suppression of anti-apoptotic signaling in axonal tracks that correlated with activation of biomarkers of the integrated stress response (ISR) in these structures after oxycodone exposure. Using MCF7 cells, we observed induction of the ISR and pro-apoptotic signaling after opioid treatment. We showed that the ISR inhibitor, ISRIB, suppresses opioid-induced Bax and CHOP expression in MCF7 cells.

CONCLUSIONS

Altogether, our data suggest that chronic opioid administration may cause neuronal degeneration by activation of the integrated stress response leading to induction of apoptotic signaling in neurons and also by promoting demyelination in CNS.

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

In environments in which opioids are increasingly abused for recreation, children are becoming more at risk for both accidental and nonaccidental intoxication. In toxic doses, opioids can cause potentially lethal acute leukoencephalopathy, which has a predilection for the cerebellum in young children. The authors present the case of a 2-year-old girl who suffered an accidental opioid overdose, presenting with altered mental status requiring cardiorespiratory support. She required emergency posterior fossa decompression, partial cerebellectomy, and CSF drainage due to cerebellar edema compressing the fourth ventricle. To the authors' knowledge, this is the first report of surgical decompression used to treat cerebellar edema associated with opioid overdose in a child.

Losses and gains: chronic pain and altered brain morphology

As in many fields of neuroscience, alterations in brain morphology, and specifically gray matter volume and cortical thickness, have been repeatedly linked to chronic pain disorders. Numerous studies have shown changes in cortical and subcortical brain regions suggesting a dynamic process that may be a result of chronic pain or contributing to a more generalized phenomenon in chronic pain including comorbid anxiety and depression. In this review, we provide a perspective of pain as an innate state of pain based on alterations in structure and by inference, brain function. A better neurobiological understanding of gray matter changes will contribute to our understanding of how structural changes contribute to chronic pain (disease driver) and how these changes may be reversed (disease modification or treatment).

Heroin spongiform leukoencephalopathy (HSLE)

PURPOSE

An increasing number of heroin addicts-especially young and first-time users-prefer inhaling the drug to intravenous injection. A rare complication of inhaling heroin is the development of a spongiform leukoencephalopathy (HSLE).

METHODS

Pathological background, symptoms, imaging, and therapeutical options are discussed on the basis of an example case.

RESULTS

Pathophysiologically, a dysfunction of the oligodendrocyte mitochondria is suspected. Three distinct stages based on key symptoms are defined. Patients may remain in one stage, or pass through two, or all three stages. Magnetic resonance imaging (MRI) is necessary for diagnosis. There are few therapeutical options. Antioxidants and coenzyme Q may be beneficial. The disorder is self-limiting in the majority of cases. Complications such as hydrocephalus and diffuse cerebellar swelling may, however, require neurosurgical intervention.

CONCLUSIONS

HSLE is a rare occurrence in patients with heroin abuse. The number of undetected cases in drug-related deaths may be high. Clinical appearance may be easily mistaken for withdrawal symptoms.

Chasing the Dragon: A Review of Toxic Leukoencephalopathy

The report begins with the case of an 18-year-old male who presented to a community hospital with difficulty walking and speaking. His illicit drug use history included smoking heroin. After admission to the hospital, a thorough workup was consistent with toxic heroin related leukoencephalopathy. The young man continued to decline and died approximately 2 months after his initial presentation and diagnosis. An autopsy and a thorough neuropathology examination were completed. Sections through the cerebral hemispheres and the cerebellum revealed diffuse and profound softening and discoloration of the white matter, most prominently in the occipital lobes. Microscopically, there was vacuolization and spongiosis of the white matter. The pathologic findings were consistent with the diagnosis of toxic or heroin related leukoencephalopathy. Toxic leukoencephalopathy is a rare disorder of unknown etiology linked to the smoking of heroin, known as “chasing the dragon.” The exact mechanism of the disorder is unknown, but it is thought that impurities cut into the heroin may become toxic substances upon sublimation, as the disorder is not seen with injected heroin. Currently, therapy is supportive with no effective cures available. The natural history of the disorder is variable, with an approximately 25% mortality rate. The popularity of smoking heroin is growing in the United States, and it is particularly seen with increasing frequency in new heroin users. Thus, this is an important, and likely increasingly common, effect of illicit drug use that should be recognized by forensic pathologists.