Delayed spongiform leukoencephalopathy after heroin abuse

A case report of long-term effects of Delayed post-hypoxic leukoencephalopathy (DPHL) following benzodiazepine overdose

Objective: We report a neuropsychological evaluation for a 39-year-old, right-handed, white female who 8 years ago developed delayed post-hypoxic leukoencephalopathy (DPHL), a rare demyelinating syndrome, two-weeks following an anoxic brain injury due to an overdose from benzodiazepines. Methods: An extensive record review documenting her medical timeline and treatment over the last 8 years was conducted using the available EMR system, which also included both EEG and neuroimaging data. Eight years post injury, a comprehensive neuropsychological battery was administered with corrected normative data for age, race, education, and other demographic factors when available. Collected data was compared with other case reports of DPHL. Results: The neuropsychological profile indicated difficulties across multiple cognitive domains that appeared driven by executive dysfunction, likely related to fronto-subcorto-striatal dysfunction. Conclusion: As a rare disease, the process by which DPHL occurs is not fully understood. Our results revealed similar findings in the literature for learning and memory, attention, processing speed, and executive functions. This is discussed in the context of available neuroimaging while highlighting the value of comprehensive neuropsychological assessment in DPHL even years post-injury.

Delayed Post-Hypoxic Leukoencephalopathy Following Nitrite Poisoning: A Case Report and Review of the Literature

Background

Delayed post-hypoxic leukoencephalopathy (DPHL) is a demyelinating syndrome that occurs days to weeks after the brain has recovered from a coma. It is caused by the period of hypoxia and is characterized by mental disorders, extrapyramidal system symptoms, and motor changes. Common causes include cardiogenic shock, severe anemia, massive blood loss, and poisoning. Poisoning, mostly resulting from intoxication with carbon monoxide and several narcotic drugs, has been reported to be a cause of DPHL. There are only a few reports of DPHL due to nitrite poisoning in literature. We report DPHL in a patient following nitrite poisoning and a review of the literature in this context.

Case Presentation

A 64-year-old man presented with dizziness and nausea without vomiting. He later went into a coma after consuming a spare rib soup. After blood gas analysis, we suspected nitrite poisoning combined with metabolic acidosis, hypoxemia, and electrolyte imbalance. He gradually showed neurologic recovery to premorbid baseline after intravenous administration of methylene blue (40 mg) and symptomatic treatment. Two months later, the patient's cerebral magnetic resonance imaging (MRI) showed signs that are compatible with injury, with the patient in late stages of mental decline.

Conclusion

Nitrite poisoning can cause DPHL. There is a period of intermittent recovery between the time of poisoning and the development of DPHL, but the specific pathogenesis and treatment are still unclear.

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.

Endogenous and exogenous opioid effects on oligodendrocyte biology and developmental brain myelination

The elevated presence of opioid receptors and their ligands throughout the developing brain points to the existence of maturational functions of the endogenous opioid system that still remain poorly understood. The alarmingly increasing rates of opioid use and abuse underscore the urgent need for clear identification of those functions and the cellular bases and molecular mechanisms underlying their physiological roles under normal and pathological conditions. This review is focused on current knowledge on the direct and indirect regulatory roles that opioids may have on oligodendrocyte development and their generation of myelin, a complex insulating membrane that not only facilitates rapid impulse conduction but also participates in mechanisms of brain plasticity and adaptation. Information is examined in relation to the importance of endogenous opioid function, as well as direct and indirect effects of opioid analogues, which like methadone and buprenorphine are used in medication-assisted therapies for opioid addiction during pregnancy and pharmacotherapy in neonatal abstinence syndrome. Potential opioid effects are also discussed regarding late myelination of the brain prefrontal cortex in adolescents and young adults. Such knowledge is fundamental for the design of safer pharmacological interventions for opioid abuse, minimizing deleterious effects in the developing nervous system.

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.

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.

Rare anoxic brain injury sequela of delayed posthypoxic leukoencephalopathy due to recreational drug overdose with benzodiazepines

A growth in recreational drug use will lead to a rise in delayed posthypoxic leukoencephalopathy cases. Physicians may inadvertently misdiagnose this rare condition as a primary psychiatric disorder by not maintaining a broad differential diagnosis.

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.

Neurotoxicology and drug-related disorders

Neuropsychiatric disorders caused by toxic substances pose a great diagnostic challenge due to the large variety of changes caused in the central and peripheral nervous system. The pathogenetic mechanisms at work are multifaceted and partly not solved. In human drug abusers (cannabis, opiates, cocaine, amphetamines, methamphetamine and "designer drugs"), a broad spectrum of central nervous system alterations are observed including infarction, intracerebral and subarachnoidal hemorrhage, hypoxic-ischemic leukoencephalopathy, infections, neuronal loss, specific astroglial and microglial reaction patterns, and vascular changes, including the endothelial cell as well as the basal lamina.

Toxic leucoencephalopathy after 'chasing the dragon'

Toxic leucoencephalopathy (TLE) is a rare neurological complication of heroin abuse. 'Chasing the dragon' is an inhalational mode of heroin abuse that originated in Southeast Asia. Intriguingly, no cases of TLE have been reported from this region, although the inhalational mode of heroin abuse is common. We herein report the case of a middle-aged man with a history of polysubstance abuse who presented with progressive neurological symptoms and progressed to an uncommunicative state. While the initial impression was that of iatrogenic parkinsonism, diffuse leucoencephalopathy with sparing of the cerebellum was noted on magnetic resonance imaging. In view of his history of inhalational heroin abuse close to the onset of the neurological symptoms, a diagnosis of TLE was made. No clinical improvement was noted with administration of a dopaminergic agent. This is the first known case of delayed TLE following heroin inhalation from Southeast Asia with the unusual feature of cerebellar sparing.

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.

Acute fatal posthypoxic leukoencephalopathy following benzodiazepine overdose: a case report and review of the literature

BACKGROUND

Among the rare neurological complications of substances of abuse is the selective cerebral white matter injury (leukoencephalopathy). Of which, the syndrome of delayed post hypoxic encephalopathy (DPHL) that follows an acute drug overdose, in addition to "chasing the dragon" toxicity which results from chronic heroin vapor inhalation remain the most commonly described syndromes of toxic leukoencephalopathy. These syndromes are reported in association with opioid use. There are very few cases in the literature that described leukoencephalopathy following benzodiazepines, especially with an acute and progressive course. In this paper, we present a patient who developed an acute severe fatal leukoencephalopathy following hypoxic coma and systemic shock induced by benzodiazepine overdose.

CASE PRESENTATION

A 19-year-old male was found comatose at home and brought to hospital in a deep coma, shock, hypoxia, and acidosis. Brain magnetic resonant imaging (MRI) revealed a strikingly selective white matter injury early in the course of the disease. The patient remained in a comatose state with no signs of neurologic recovery until he died few weeks later following an increase in the brain edema and herniation.

CONCLUSION

Toxic leukoencephalopathy can occur acutely following an overdose of benzodiazepine and respiratory failure. This is unlike the usual cases of toxic leukoencephalopathy where there is a period of lucidity between the overdose and the development of white matter disease. Unfortunately, this syndrome remains of an unclear pathophysiology and with no successful treatment.

Pyrolysis of drugs of abuse: a comprehensive review

This review summarizes the literature to date relating to pyrolysis and heated vapour ingestion of drugs of abuse. In this context, heating is referred to as smoking or pyrolysis, but these are generic descriptors that encompass numerous methods of vapour generation and inhalation. Depending on the amount of drug used, diluents and contaminants present, heating conditions, and the oxidative/reductive environment, many thermal decomposition products can be formed. In addition to the recognized hazard of rapid onset of pharmacological effects of the parent drug, thermal decomposition products may be pharmacologically active as well as acutely/chronically toxic. For example, several published reports have linked heroin smoking to a form of brain encephalopathy and to the development of movement disorders. Early qualitative studies focusing on the thermal decomposition of drugs have evolved into more complex investigations employing mass spectral identification, confirmation, and elucidation of formation mechanism. In most cases, thermal decomposition begins with cleavage of the weakest bond (often C-N) to generate free radicals that then form the most stable sterically favoured products. Several reports of rearrangements at higher temperatures have been identified and hint at an underlying complexity that arises from the variety of smoking methods and conditions. Given that many designer drugs such as synthetic cannabinoids are ingested primarily through smoking, this issue has taken on new importance.

Neuropathology of substance use disorders

Addictions to licit and illicit drugs are chronic relapsing brain disorders that affect circuits that regulate reward, motivation, memory, and decision-making. Drug-induced pathological changes in these brain regions are associated with characteristic enduring behaviors that continue despite adverse biopsychosocial consequences. Repeated exposure to these substances leads to egocentric behaviors that focus on obtaining the drug by any means and on taking the drug under adverse psychosocial and medical conditions. Addiction also includes craving for the substances and, in some cases, involvement in risky behaviors that can cause death. These patterns of behaviors are associated with specific cognitive disturbances and neuroimaging evidence for brain dysfunctions in a diverse population of drug addicts. Postmortem studies have also revealed significant biochemical and/or structural abnormalities in some addicted individuals. The present review provides a summary of the evidence that has accumulated over the past few years to implicate brain dysfunctions in the varied manifestations of drug addiction. We thus review data on cerebrovascular alterations, brain structural abnormalities, and postmortem studies of patients who abuse cannabis, cocaine, amphetamines, heroin, and "bath salts". We also discuss potential molecular, biochemical, and cellular bases for the varied clinical presentations of these patients. Elucidation of the biological bases of addiction will help to develop better therapeutic approaches to these patient populations.

[Delayed posthypoxic leukoencephalopathy: case reports]

Delayed posthypoxic leukoencephalopathy (DPL) is a rare and less well known complication of hypoxic brain injury. Although it is well known that anoxic or hypoxic injury produces acute neurologic deficits, DPL typically manifests days to weeks after apparent recovery from an obtunded state, and patients with DPL demonstrate cognitive impairment, high brain dysfunction, parkinsonism, or psychosis. MRI findings of the brain demonstrate deep white matter abnormalities. We report 2 cases of DPL after hypoxia due to benzodiazepine overdose. Both of our patients had normal arylsulfatase A activity. Although DPL is seen in carbon monoxide poisoning, pseudodeficiency of arylsulfatase A activity, or drug overdose with heroin or morphine, there are only some previous studies of DPL caused by an overdose with benzodiazepine. It is unclear whether neurotoxicity from the drug in addition to hypoxia alone is involved, however, it is important to note that overdose of common drugs as sleeping medicine can cause DPL. Since DPL may often be misdiagnosed and be subjected to unnecessary treatments, it is also important to understand its unique clinical course and MRI findings. With prompt recognition of DPL, we expect that more cases of DPL caused by overdose with benzodiazepine will be diagnosed, because benzodiazepine overdoses are common.

Opiate drug use and the pathophysiology of neuroAIDS

Opiate abuse and HIV-1 have been described as interrelated epidemics, and even in the advent of combined anti-retroviral therapy, the additional abuse of opiates appears to result in greater neurologic and cognitive deficits. The central nervous system (CNS) is particularly vulnerable to interactive opiate-HIV-1 effects, in part because of the unique responses of microglia and astroglia. Although neurons are principally responsible for behavior and cognition, HIV-1 infection and replication in the brain is largely limited to microglia, while astroglia and perhaps glial progenitors can be latently infected. Thus, neuronal dysfunction and injury result from cellular and viral toxins originating from HIV-1 infected/exposed glia. Importantly, subsets of glial cells including oligodendrocytes, as well as neurons, express µ-opioid receptors and therefore can be direct targets for heroin and morphine (the major metabolite of heroin in the CNS), which preferentially activate µ-opioid receptors. This review highlights findings that neuroAIDS is a glially driven disease, and that opiate abuse may act at multiple glial-cell types to further compromise neuron function and survival. The ongoing, reactive cross-talk between opiate drug and HIV-1 co-exposed microglia and astroglia appears to exacerbate critical proinflammatory and excitotoxic events leading to neuron dysfunction, injury, and potentially death. Opiates enhance synaptodendritic damage and a loss of synaptic connectivity, which is viewed as the substrate of cognitive deficits. We especially emphasize that opioid signaling and interactions with HIV-1 are contextual, differing among cell types, and even within subsets of the same cell type. For example, astroglia even within a single brain region are heterogeneous in their expression of µ-, δ-, and κ-opioid receptors, as well as CXCR4 and CCR5, and Toll-like receptors. Thus, defining the distinct targets engaged by opiates in each cell type, and among brain regions, is critical to an understanding of how opiate abuse exacerbates neuroAIDS.

White matter abnormalities correlating with memory and depression in heroin users under methadone maintenance treatment

Methadone maintenance treatment (MMT) has elevated rates of co-morbid memory deficit and depression that are associated with higher relapse rates for substance abuse. White matter (WM) disruption in MMT patients have been reported but their impact on these co-morbidities is unknown. This study aimed to investigate changes in WM integrity of MMT subjects using diffusion tensor image (DTI), and their relationship with history of heroin and methadone use in treated opiate-dependent individuals. The association between WM integrity changes from direct group comparisons and the severity of memory deficit and depression was also investigated. Differences in WM integrity between 35 MMT patients and 23 healthy controls were evaluated using DTI with tract-based spatial statistical analysis. Differences in DTI indices correlated with diminished memory function, Beck Depression Inventory, duration of heroin use and MMT, and dose of heroin and methadone administration. Changes in WM integrity were found in several WM regions, including the temporal and frontal lobes, pons, cerebellum, and cingulum bundles. The duration of MMT was associated with declining DTI indices in the superior longitudinal fasciculus and para-hippocampus. MMT patients had more memory and emotional deficits than healthy subjects. Worse scores in both depression and memory functions were associated with altered WM integrity in the superior longitudinal fasciculus, para-hippocampus, and middle cerebellar peduncle in MMT. Patients on MMT also had significant WM differences in the reward circuit and in depression- and memory-associated regions. Correlations among decreased DTI indices, disease severity, and accumulation effects of methadone suggest that WM alterations may be involved in the psychopathology and pathophysiology of co-morbidities in MMT.

Hypoxic Brain Injury Following Heroin Overdose

Hypoxic brain injury is an under-recognised consequence of heroin overdose. This article documents the disability experienced by 10 people with hypoxic brain injuries following heroin overdose who presented in the 2-year period July 1997 to June 1999 at the Royal Talbot Rehabilitation Centre, a brain injury rehabilitation facility in Melbourne, Australia. Medical histories of these clients were reviewed and follow-up interviews were conducted between 2 and 4 years postinjury. Measures included the Functional Independence Measure (FIM) and the Community Integration Questionnaire (CIQ). The results showed that there were significant and enduring consequences for most of the 10 participants. At follow-up two participants had died from subsequent overdose, three required support to live in the community and one lived in an aged care facility. Only one participant was able to return to work. Cognitive problems were present in most of the group and problem solving and social interaction difficulties were the most commonly recorded problems. Three cases are described in detail to highlight some of the significant issues identified in this sample. Implications for the rehabilitation of people with brain injury following heroin overdose are discussed.

Delayed hypoxic-ischemic leukoencephalopathy

A 55-year-old female was found unconscious in a ventilated room. She recovered consciousness on the way to the emergency room. Her vital signs were stable. She presented with negativism and poor communication. Physical examination, routine tests, brain CT and electroencephalogram were normal. Urine toxicology was positive for benzodiazepines. Twelve days after, she presented with catatonia and immobility. Additional examinations, including cerebrospinal fluid (CSF) testing and brain CT, were again normal. Risperidone was administered, and psychotherapy intensified. In the third week, the condition worsened, with intense pyramidal signs and decerebration that led to a vegetative state. Brain MRI revealed diffuse leukoencephalopathy. Extensive metabolic and CSF studies were persistently negative. Brain biopsy was compatible with chronic cerebral hypoxia/anoxia. A diagnosis of delayed hypoxic-ischemic leukoencephalopathy was made. Supportive measures were intensified. She was discharged from the hospital after 4 months in a minimally conscious state and was capable of elementary communication and recognising faces.

[Toxic leucoencephalopathy after use of sniffed heroin, an unrecognized form of beneficial evolution]

INTRODUCTION

Serious leukoencephalopathy can be related to heroin injection or inhalation.

OBSERVATION

We report the first case of leukoencephalopathy observed three weeks after a 46-year-old man sniffed heroin. The clinical presentation included cognitive and behaviour disorders, pyramidal irritation and slight gait instability. Blood and cerebrospinal fluid analyse were normal. Brain magnetic resonance imaging showed diffuse, symmetrical supratentorial white matter lesions producing high intense signals on FLAIR and b1000-weighted sequences. Proton spectroscopy revealed an increased rate of cholin, in favour of active demyelinated lesions. Brain biopsy showed intramyelinic oedema with reactive gliosis. After two and a half years, moderate attentional fluctuations and difficulties in initiating activities persisted. Repeated MRI showed a reduction of the leukoencephalopathy.

CONCLUSION

Heroin could be a cause more common than thought of leukoencephalopathy. The clinical and radiological expression and prognosis could be related to the mode of consummation (inhalation, intravenous injection, sniffing). This parameter may modulate severity and localization of brain lesions. More systematic use of MRI for patients with psychiatric symptoms after heroin intoxications could lead to a better evaluation of heroin-related neurotoxicity and potentially improve prevention.

Chasing the dragon - characterizing cases of leukoencephalopathy associated with heroin inhalation in British Columbia

An association between leukoencephalopathy, a disease of the white matter of the brain, and smoking heroin is well recognized. This paper describes 27 cases of leukoencephalopathy identified in two cities in British Columbia, Canada 2001-2006; the largest number of geographically and temporally defined reported cases in North America.

Twenty cases of leukoencephalopathy were identified in and around Vancouver with onset dates December 2001 to July 2003; seven further cases were identified in Victoria September 2005-August 2006. Twenty (74%) of all cases were male, two couples were reported and eleven cases (55%) had Asian ethnicity. One case reported smoking heroin on a single occasion and developed mild symptoms; all other cases were hospitalized. Thirteen (48%) cases died; all had smoked heroin for a minimum of 3 years. Testing of one available heroin sample identified no substance other than common cutting agents.

Although a specific etiology was not identified our study supports the theory of an intermittent exposure to a toxic agent added to the heroin or a combustion by-product. It also suggests a dose response effect rather than genetic predisposition. Collaboration with public health, health professionals, law enforcement and persons who use illegal drugs, will facilitate the early identification of cases to enable timely and complete follow-up including obtaining samples. Testing of implicated heroin samples may allow identification of the contaminant and therefore prevent further cases. It is therefore important to ensure key stakeholders are aware of our findings.

Severe leukoencephalopathy following acute oxycodone intoxication

BACKGROUND

Post-opioid toxic encephalopathy is described associated with the synthetic opioid, methadone, and after heroin intoxication, (inhaled, injected or ingested).

METHODS

We describe the clinical and radiologic findings of a 46-year-old man with oxycodone and oxycontin overdose who developed multifocal encephalopathy and severe cerebellitis causing acute obstructive hydrocephalus, and discuss the possible mechanisms involved.

RESULTS

Brain MRI showed a non-vascular distribution of diffusion positive lesions in both cerebellar hemispheres and globi pallidi with preserved cerebral perfusion, suggesting an inflammatory process. Management required ventilatory support and intraventricular catheter placement.

CONCLUSIONS

To our knowledge, this is the first report of this condition associated with oxycodone and oxycontin ingestion. The occurrence of this rare toxic encephalopathy may be related to distribution patterns of opioid receptor subtypes, genetic susceptibility, sensitization, and other specific comorbidities.

Rhabdomyolysis and brain ischemic stroke in a heroin-dependent male under methadone maintenance therapy

OBJECTIVE

There are several complications associated with heroin abuse, some of which are life-threatening. Methadone may aggravate this problem.

METHOD

A clinical case description.

RESULTS

A 33-year-old man presented with rhabdomyolysis and cerebral ischemic stroke after intravenous heroin. He had used heroin since age 20, and had used 150 mg methadone daily for 6 months. He was found unconsciousness at home and was sent to our hospital. In the ER, his opiate level was 4497 ng/ml. In the ICU, we found rhabdomyolysis, acute renal failure and acute respiratory failure. After transfer to an internal ward, we noted aphasia and weakness of his left limbs. After MRI, we found cerebral ischemic infarction.

CONCLUSION

Those using methadone and heroin simultaneously may increase risk of rhabdomyolysis and ischemic stroke. Patients under methadone maintenance therapy should be warned regarding these serious adverse events. Hypotheses of heroin-related rhabdomyolysis and stroke in heroin abusers are discussed.

An unsuccessful trial of immunomodulatory therapy in delayed posthypoxic demyelination

INTRODUCTION

Delayed posthypoxic demyelination may rarely complicate an episode of severe hypoxia, with or without exposure to carbon monoxide. Following recovery from initial coma, progressive neurologic deterioration ensues with outcomes ranging from death to full recovery. Delayed posthypoxic demyelination is hypothesized to be immunemediated, with support coming from recent animal experiments.

METHODS

We report a 46-year-old man who developed progressive cognitive deficits with abulia approximately 3 weeks after recovering from coma related to alcohol and morphine intoxication.

RESULTS

Despite treatment with high-dose steroids and plasmapheresis, he continued to deteriorate and remained in a vegetative state until his death under hospice care more than 2 months after his initial hypoxic insult. Serial brain imaging and postmortem examination showed bilateral necrosis of the globi pallidi and extensive demyelination in the centrum semiovale and corona radiata.

CONCLUSIONS

Based on an immune-mediated model of disease and given a lack of effective treatments, future use of immunomodulatory therapy may still be worth considering early in the course of this rare and potentially devastating condition.

Widespread axonal damage in the brain of drug abusers as evidenced by accumulation of beta-amyloid precursor protein (beta-APP): an immunohistochemical investigation

BACKGROUND

In drug abusers, white matter changes have been described by neuroimaging analyses in different brain regions. A specific pattern of involvement or a predominance of a specific brain region could not be drawn.

AIMS

To examine alterations of the white matter as a possible morphological substrate of the neuroimaging findings.

METHODS

Brain specimens of 30 polydrug abusers and 20 controls were obtained at autopsy. The white matter from 11 different brain regions was analysed by means of immunohistochemistry for beta-amyloid precursor protein (beta-APP), a marker of axonal damage.

FINDINGS

In the white matter of polydrug abusers, beta-APP-immunopositive accumulations were increased significantly compared to controls. They were more prominent in the brains of younger drug abusers than in those of the elderly. With the exception of five cases (four polydrug abusers and one control case), there were no significant white matter changes seen on myelin-stained sections, but there was a concomitant microglial activation.

CONCLUSIONS

Our results show a significant axonal damage in the brains of polydrug abusers, which might represent the morphological substrate of a chronic-progressive drug-induced toxic-metabolic process. It is yet to be established if the observed changes are responsible for the alterations seen in different neuroimaging analyses and which drugs of abuse might be of major pathogenetic significance.

Development of pharmaceutical heroin preparations for medical co-prescription to opioid dependent patients

Presently, there is a considerable interest in heroin-assisted treatment: co-prescription of heroin to certain subgroups of chronic, treatment-resistant, opioid dependent patients. In 2002, nine countries had planned (Australia, Belgium, Canada, France, Spain) or ongoing (Germany, The Netherlands, Switzerland, United Kingdom) clinical trials on this subject. These trials (and the routine heroin-assisted treatment programs that might result) will need pharmaceutical heroin (diacetylmorphine) to prescribe to the patients. Research into the development of pharmaceutical forms of heroin for prescription to addicts can benefit from the large amount of knowledge that already exists regarding this substance. Therefore, in this paper we review the physicochemical and pharmaceutical properties of diacetylmorphine and the clinically investigated routes of administration, as well as routes of administration utilised on the street in the context of developing pharmaceutical heroin formulations for prescription to addicts. Patient acceptability of the formulation is essential, because heroin-assisted treatment is aimed at treatment-resistant addicts, who often have to be encouraged to participate (or to maintain participation) in a treatment program. This means that the most suitable products would have pharmacokinetic profiles mimicking that of diacetylmorphine for injection, with rapid peak concentrations of diacetylmorphine and 6-acetylmorphine, ensuring the 'rush effect' and the sustained presence of morphine(-6-glucuronide) creating the prolonged euphoria. Diacetylmorphine for inhalation after volatilisation (via 'chasing the dragon') seems to be a suitable candidate, while intranasal and oral diacetylmorphine are currently thought to be unsuitable. However, oral and intranasal delivery systems might be improved and become suitable for use by heroin dependent patients.

[Delayed post-anoxic leukoencephalopathy]

INTRODUCTION

The onset of post-anoxic encephalopathies can be delayed after the acute hypoxic injury.

CASE REPORT

We present the case of a 45-year-old woman who achieved complete recovery from an episode of hypoxia related to a suicide attempt (ingestion of benzodiazepine). Three weeks later she developed a confusional state with akinetic mutism and parkinsonism. Brain CT-scan showed bilateral hemispheric white matter hypodensities. MRI showed extensive bilateral hyperintensities on T2-weighted and Flair sequences within the hemispheric white matter and the globus pallidus. EEG showed diffuse slow activity. All investigations for leukodystrophies were negative. Brain biopsy showed normal cortex and widespread demyelination with axonal sparing in the underlying white matter. The patient experienced a partial clinical recovery.

CONCLUSION

The clinical course and the results of paraclinic investigations were consistent with the diagnosis of delayed post-anoxic leukoencephalopathy.

Reversible parkinsonism following heroin pyrolysate inhalation is associated with tetrahydrobiopterin deficiency

A patient who inhaled heroin vapour (chasing the dragon), resulting in temporary parkinsonism, is described. A reversible deficiency of tetrahydrobiopterin, causing altered dopamine metabolism, is demonstrated as the metabolic basis of this aspect of the encephalopathy.

Preferential vulnerability of astroglia and glial precursors to combined opioid and HIV-1 Tat exposure in vitro

Human immunodeficiency virus (HIV)-1 infection can cause characteristic neural defects such as progressive motor dysfunction, striatal pathology and gliosis. Recent evidence suggests that HIV-induced pathogenesis is exacerbated by heroin abuse and that the synergistic neurotoxicity is a direct effect of heroin on the CNS, an alarming observation considering the high incidence of HIV infection with injection drug abuse. Although HIV infection results in neurodegeneration, neurons themselves are not directly infected. Instead, HIV affects microglia and astroglia, which subsequently contributes to the neurodegenerative changes. Opioid receptors are widely expressed by macroglia and macroglial precursors, and the activation of mu-opioid receptors can modulate programmed cell death, as well as the response of neural cells to cytotoxic insults. For this reason, we questioned whether opioid drugs might modify the vulnerability of macroglia and macroglial precursors to HIV-1 Tat protein. To address this problem, the effects of morphine and/or HIV Tat(1-72) on the viability of macroglia and macroglial precursors were assessed in mixed-glial cultures derived from mouse striatum. Our findings indicate that sustained exposure to morphine and Tat(1-72) viral protein induces the preferential death of glial precursors and some astrocytes. Moreover, the increased cell death is mediated by mu-opioid receptors and accompanied by the activation of caspase-3. Our results imply that opiates can enhance the cytotoxicity of HIV-1 Tat through direct actions on glial precursors and/or astroglia, suggesting novel cellular targets for HIV-opiate interactions.

Spongiform leucoencephalopathy following intravenous heroin abuse: radiological and histopathological findings

A case of spongiform leucoencephalopathy in a known intravenous heroin abuser is presented. To our knowledge, this is the only case of heroin-related spongiform leucoencephalopathy reported in Australia. The relationship to intravenous rather than inhaled heroin is particularly unusual with only one other possible case documented in the literature. The imaging and histopathological findings are described.

Reversible delayed leukoencephalopathy following intravenous heroin overdose

We present serial neuropsychological, magnetic resonance (MR) imaging and EEG changes in a case of widespread CNS myelinopathy due to intravenous heroin overdose complicated by a period of prolonged unconsciousness. Following recovery from the acute overdose, the subject had the delayed onset of akinetic mutism with urinary incontinence. Sequential formal neuro-psychological assessments over 9 months showed evolution from severe global cerebral dysfunction to moderate disturbance of frontal lobe function. Almost complete resolution of diffuse white matter signal changes, accompanied by the development of a degree of volume loss, was evident on serial MR imaging over the same period, and generalized arrhythmic delta-range slowing on the EEG evolved int o a near normal pattern.

The neuropathology of heroin abuse

A broad spectrum of neuropathologic changes are encountered in the brains of heroin abusers. The main findings are due to infections, either due to bacterial spread from bacterial endocarditis, mycoses, or from HIV-1 infection. Other complications include hypoxic-ischemic changes with cerebral edema, ischemic neuronal damage and neuronal loss, which are assumed to occur under conditions of prolonged heroin-induced respiratory depression, stroke due to, for example, thromboembolism, vasculitis, septic emboli, hypotension, and positional vascular compression. Myelopathy is believed to be the result of an isolated vascular accident within the spinal cord due to an as yet unknown mechanism. A distinct entity, spongiform leukoencephalopathy, has been described mainly after inhalation of pre-heated heroin. A lipophilic toxin-induced process was considered to be due to contaminants and to be induced or enhanced by cerebral hypoxia, but a definite toxin could not be identified. At the cellular level, abnormalities in signal transduction systems and changes of various receptor densities have been reported. The exact etiology of the different neuropathological alterations associated with heroin abuse is still unclear, but may also be related to additional substances used as adulterants.