Heroin spongiform leukoencephalopathy (HSLE)

Opioid-Associated Nervous System Injuries

With the rise of the opioid epidemic, the practicing neurologist must recognize the patterns of a growing number of opioid-associated neurological injuries. This is in addition to the classic toxidrome of miosis, altered mental status, and respiratory depression, which must never be overlooked, as it is reversible and potentially lifesaving. Several other idiosyncratic syndromes due to opioid-related nervous system insults are defined by their characteristic imaging findings and portend variable functional recovery. Opioid toxicity can not only lead to brain injury, but also spinal cord and, rarely, peripheral nerve injury. As several newer synthetic opioids are undetectable by most assays, a low threshold to suspect opioid exposure must be maintained.

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.

Spongiform leukoencephalopathy: A unique case of biopsy confirmed leukoencephalopathy secondary to toxic, non-inflammatory exposure

Toxin-induced leukoencephalopathy is a rare neurological condition that has been previously associated with intracranial radiation, chemotherapy, drugs of abuse, and environmental exposures. Herein, we present a patient with brain-biopsy proven toxin-induced leukoencephalopathy, likely secondary to multiple environmental offenders including insecticides and non-Food and Drug Administration approved anabolic steroids, opioids, and benzodiazepines. A 60-year-old man presented to our service as a direct transfer from an outside facility for evaluation of a rapidly progressive neuropsychiatric decline. Extensive workup with blood work, cerebrospinal fluid analysis, paraneoplastic panel, serial magnetic resonance imaging brain with and without contrast, and electroencephalograms were unrevealing. Magnetic resonance imaging brain showed diffuse confluent white matter disease, which was non-specific. The patient was treated with high-dose methylprednisolone and trials of intravenous immunoglobulin without any significant improvement. Finally, a brain biopsy was performed, and pathology confirmed a spongiform leukoencephalopathy, favoring a toxin-related etiology. The diagnosis of toxin-induced leukoencephalopathy should be considered in patients with steep neuropsychiatric decline and associated diffuse white matter disease. Diagnosis relies heavily on history of exposure, clinical presentation, imaging findings, and ultimately, histopathology from brain biopsy. The recognition of the clinical presentation is important to pursue the appropriate diagnostic workup and treatment.

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.

Single-Cell RNA-Seq Uncovers a Robust Transcriptional Response to Morphine by Glia

Molecular and behavioral responses to opioids are thought to be primarily mediated by neurons, although there is accumulating evidence that other cell types play a prominent role in drug addiction. To investigate cell-type-specific opioid responses, we performed single-cell RNA sequencing (scRNA-seq) of the nucleus accumbens of mice following acute morphine treatment. Differential expression analysis uncovered unique morphine-dependent transcriptional responses by oligodendrocytes and astrocytes. We examined the expression of selected genes, including Cdkn1a and Sgk1, by FISH, confirming their induction by morphine in oligodendrocytes. Further analysis using RNA-seq of FACS-purified oligodendrocytes revealed a large cohort of morphine-regulated genes. The affected genes are enriched for roles in cellular pathways intimately linked to oligodendrocyte maturation and myelination, including the unfolded protein response. Altogether, our data illuminate the morphine-dependent transcriptional response by oligodendrocytes and offer mechanistic insights into myelination defects associated with opioid abuse.

The Emerging Role of Inhaled Heroin in the Opioid Epidemic: A Review

Importance

Opioid addiction affects approximately 2.4 million Americans. Nearly 1 million individuals, including a growing subset of 21 000 minors, abuse heroin. Its annual cost within the United States amounts to $51 billion. Inhaled heroin use represents a global phenomenon and is approaching epidemic levels east of the Mississippi River as well as among urban youth. Chasing the dragon (CTD) by heating heroin and inhaling its fumes is particularly concerning, because this method of heroin usage has greater availability, greater ease of administration, and impressive intensity of subjective experience (high) compared with sniffing or snorting, although it also has a safer infectious profile compared with heroin injection. This is relevant owing to peculiar and often catastrophic brain complications. Following the American Medical Association Opioid Task Force mandate, we contribute a description of the pharmacology, pathophysiology, clinical spectrum, neuroimaging, and neuropathology of CTD leukoencephalopathy, as distinct from other heroin abuse modalities.

Observations

The unique spectrum of CTD-associated health outcomes includes an aggressive toxic leukoencephalopathy with pathognomonic neuropathologic features, along with sporadic instances of movement disorders and hydrocephalus. Clinical CTD severity is predominantly moderate at admission, frequently unmodified at discharge, and largely improved in the long term. Mild cases survive with minor sequelae, while moderate to severe presentations might deteriorate and progress to death. Other methods of heroin use may complicate with stroke, seizure, obstructive hydrocephalus, and (uncharacteristically) leukoencephalopathy.

Conclusions and Relevance

The distinct pharmacology of CTD correlates with its specific clinical and radiological features and prompts grave concern for potential morbidity and long-term disability costs. Proposed diagnostic criteria and standardized reporting would ameliorate the limitations of CTD literature and facilitate patient selection for a coenzyme Q10 therapeutic trial.

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.

Chasing the wrong dragon: A new presentation of heroin-induced toxic leukoencephalopathy mimicking anoxic brain injury

Toxic leukoencephalopathy associated with heroin inhalation has been extensively described in the literature. This syndrome is characterized by progressive motor symptoms and dysautonomia that develop over weeks to months. We present three cases of abrupt-onset inhaled heroin-associated toxic leukoencephalopathy, a previously undescribed entity. These likely represent a subset of "found down" patients with acute neurologic changes not attributable to hypoxemic encephalopathy. All three had magnetic resonance imaging findings characteristic of toxic leukoencephalopathy, which has a relatively favorable prognosis. Prolonged unresponsiveness in patients "found down" after heroin overdose is often attributed to hypoxic brain injury. Brain magnetic resonance imaging is not generally included as part of routine workup. It should, however, be considered in patients with suspected inhaled heroin use due to the relatively favorable prognosis of toxic leukoencephalopathy. This is especially relevant in the setting of the current opioid epidemic and related increase in overdose-related intensive care unit admissions. The result may have significant impact on decisions about therapeutic options or continuation of care.

Methamphetamine-induced toxic leukoencephalopathy: clinical, radiological and autopsy findings

Toxic leukoencephalopathy represents a process of structural alteration of the white matter. It is caused by substance abuse including drugs such as heroin, cocaine, toluene and ethanol. We reported the clinical, radiological and autopsy findings of a rare case of toxic leukoencephalopathy following chronic methamphetamine (MA) usage. A 34-year-old man with a 3-year history of MA abuse experienced progressive sluggish state, limb weakness, inability to stand and eating disorders, followed by rapid progression to coma and death. Imaging revealed hypodense CT and long T1 and T2 signals in MRI in the white matter of the bilateral periventricular and centrum semiovale regions. Histologically, white matter rarefaction, loss of myelin and axonal injury were observed. This pattern of clinical presentation, radiological manifestations and histological findings show a certain degree of particularity in toxic leukoencephalopathy. Clinically, the condition may be easily misdiagnosed as withdrawal symptoms. In suspected cases, MRI is recommended for diagnosis. The case reported here reminds clinicians and forensic pathologist of the possibility of toxic leukoencephalopathy related to MA abuse.

Acute brain injury following illicit drug abuse in adolescent and young adult patients: spectrum of neuroimaging findings

The use of illicit drugs is currently a major medical problem among adolescents. Several illicit drugs have a high abuse potential and can be neurotoxic causing high morbidity and mortality. The clinical manifestation of adolescents with acute drug-induced neurotoxicity is often characterized by non-specific symptoms and findings. Early diagnosis is important to prevent death and permanent long-term neurological impairments. We report on clinical and neuroimaging findings in five adolescents with acute brain imaging following illicit drug intoxication to highlight the role of neuroimaging findings in the diagnostic work-up of pediatric acute drug-induced neurotoxicity. Our patients reveal two main neuroimaging patterns of brain injury: diffuse symmetric subcortical white matter injury with preferential cerebellar involvement (leukoencephalopathy pattern) or multiple foci of ischemic infarctions in a non-arterial territory distribution (ischemic pattern). Familiarity with these two neuroimaging patterns of findings in the evaluation of magnetic resonance imaging studies in adolescents with acutely altered mental status may suggest the correct diagnosis, narrow the differential diagnosis, and consequently allow early initiation of targeted laboratory investigations and treatment, potentially improving outcome.

Emerging and Underrecognized Complications of Illicit Drug Use

Illicit drug use can result in a wide range of medical complications. As the availability, synthesis, and popularity of illicit drugs evolve over time, new syndromes associated with their use may mimic infections. Some of these symptoms are anticipated drug effects, and others are complications of adulterants mixed with drugs or complications from the method of using drugs. Some illicit drugs are associated with rare infections, which are difficult to diagnosis with standard microbiological techniques. The goal of this review is to orient a wide range of clinicians-including general practitioners, emergency medicine providers, and infectious diseases specialists-to complications of illicit drug use that may be underrecognized. Improving awareness of infectious and noninfectious complications of illicit drug can expedite diagnosis and medical treatment of persons who use drugs and facilitate targeted harm reduction counseling to prevent future complications.