An Autopsy Case of Dextromethorphan Poisoning.

A woman in her 30s who was being treated for a mental illness with several psychotropic drugs was admitted to the hospital after being found in a state of unconsciousness and respiratory arrest at home. She was pronounced dead 12 hours after she was discovered. Her autopsy revealed symmetrical hemorrhagic necrosis in the putamen on both sides of her cerebrum. Although many drugs were detected in her blood, all of those other than dextromethorphan (DXM) were within or below the therapeutic range. Her blood DXM was 1.73 µg/ml at admission and 1.61 µg/ml at autopsy, which were within the toxic range or coma-to-death range. The cause of death was diagnosed as DXM poisoning. DXM can cause hallucinations and euphoria if taken in excess, but since it is available as an over-the-counter drug at general pharmacies, an increasing number of young people are overdosing on it, mistakenly believing it to be a safe drug with few side effects. We believe that further social measures against DXM are necessary in Japan, such as disseminating correct knowledge in society and regulating over-the-counter sales.

The characteristics and prevalence of patent foramen ovale in Japanese people: a study using material from forensic autopsies.

Racial and ethnic differences in the prevalence of patent foramen ovale have been suggested, but there are insufficient data to confirm the situation. Studies have also not investigated detailed morphological changes in the fossa ovalis by age. This study therefore aimed to clarify the characteristics of the fossa ovalis and determine the frequency of patent foramen ovale in Japanese people, using materials from forensic autopsies. A total of 359 hearts were obtained during forensic autopsies (from 223 males and 136 females, aged from 0 to 94 years). Overall, prevalence of patent foramen ovale was 12.5%, but it was significantly higher among those under 20 years old (66.7% in males, 38.5% in females). The area of the fossa ovalis linearly increased with age in both sexes. The prevalence of patent foramen ovale was lower in Japanese adults than previously found in either White or Black people. The ratio of the area of the fossa ovalis to the heart weight was nearly constant.

Postmortem imaging reveals patterns of medial temporal lobe vulnerability to tau pathology in Alzheimer's disease.

Our current understanding of the spread and neurodegenerative effects of tau neurofibrillary tangles (NFTs) within the medial temporal lobe (MTL) during the early stages of Alzheimer's Disease (AD) is limited by the presence of confounding non-AD pathologies and the two-dimensional (2-D) nature of conventional histology studies. Here, we combine ex vivo MRI and serial histological imaging from 25 human MTL specimens to present a detailed, 3-D characterization of quantitative NFT burden measures in the space of a high-resolution, ex vivo atlas with cytoarchitecturally-defined subregion labels, that can be used to inform future in vivo neuroimaging studies. Average maps show a clear anterior to poster gradient in NFT distribution and a precise, spatial pattern with highest levels of NFTs found not just within the transentorhinal region but also the cornu ammonis (CA1) subfield. Additionally, we identify granular MTL regions where measures of neurodegeneration are likely to be linked to NFTs specifically, and thus potentially more sensitive as early AD biomarkers.

Cytomegalovirus pneumonia with intermittent pulmonary hemorrhage leading to asphyxia death: a case report and literature review.

Neonatal pulmonary hemorrhage is a late manifestation of various diseases. Premature delivery and low body weight are frequently observed as high-risk factors, characterized by acute onset, rapid progression, and high mortality rates. Pulmonary hemorrhage caused by cytomegalovirus infection in newborns with normal immune function is a rare occurrence. This case report focuses on a term neonate with normal birth weight who presented solely with nasal obstruction shortly after birth. However, 4 days after birth, the newborn experienced a sudden onset of blood gushing from both the mouth and nasal cavity. The patient was diagnosed with gastrointestinal bleeding, neonatal pneumonia and neonatal lung consolidation. And he was discharged after ten days of symptomatic treatment. However, upon returning home, the patient experienced a sudden onset of bleeding from the mouth and nose, leading to his untimely demise. Subsequent autopsy revealed the presence of pulmonary hemorrhage in newborn, which presented as interstitial pneumonia. The cause of pulmonary hemorrhage is cytomegalovirus infection. This case emphasizes the importance of pediatricians enhancing their skills in differentiating pulmonary hemorrhage, especially from cytomegalovirus pneumonia.

Identification of post-mortem product of zolpidem degradation by hemoglobin via the Fenton reaction.

Zolpidem, N,N-dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide, is a hypnotic agent widely used in clinical practice but is detected in many clinical cases of fatal intoxication and suicide. In forensic toxicology, the precise determination of zolpidem concentration in blood is a must to provide concrete evidence of death by zolpidem poisoning. However, the concentrations of zolpidem in blood at autopsy often differ from those at the estimated time of death. In the present study, we found that zolpidem was degraded by hemoglobin (Hb) via the Fenton reaction at various temperatures. The mechanism underlying zolpidem degradation involved the oxidation of its linker moiety. The MS and MS/MS spectra obtained by liquid chromatography quadrupole-Orbitrap mass spectrometry (LC-Q-Orbitrap-MS) showed the formation of 2-hydroxy-N,N-dimethyl-2-(6-methyl-2-(p-tolyl)imidazo[1,2-a]pyridin-3-yl)acetamide (2-OH ZOL) in Hb/H2O2 solution incubated with zolpidem and in the blood of several individuals who died from ingestion of zolpidem. These results suggest that 2-OH ZOL is the post-mortem product of zolpidem degradation by Hb via the Fenton reaction.

The need to update reference values for organ weights in the adult population: a review and future directions.

This review article highlights the crucial role of organ weights and dimensions as key indicators in forensic diagnosis. Organ weight changes serve as valuable markers for pathological conditions, aiding forensic doctors in interpreting autopsy findings. The review emphasizes the importance of precision in establish- ing organ reference values, considering factors like population-specific norms and correlations with body parameters. Furthermore, it explores the impact of obesity on organ weights, emphasizing the need for updated databases that accurately reflect diverse populations. The article underscores the inadequacy of relying on outdated sources and advocates for creating a comprehensive and updated database of organ weights and dimensions for the local population, essential for accurate forensic interpretations.

THE PRESENCE OF FLUIDS IN THE PARANASAL SINUSES MIGHT COMPLEMENT OTHER POST-MORTEM DIAGNOSTIC METHODS TO CONFIRM OR REFUTE DROWNING AS THE CAUSE OF DEATH.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: da Trindade RQ, Vieira MG, Vieira RB, Vicentin-Junior CA, Damascena NP, Santiago BM, Martins-Filho PR, Machado CE. The role of paranasal sinus fluid in determining drowning as the cause of death: a systematic review and meta-analysis. J forensic Leg Med. 2023;12:102591. SOURCE OF FUNDING: No funding was received for this review. TYPE OF STUDY/DESIGN: Systematic review (SR) with meta-analysis (MA) of data.

[Sudden death in adults : Data from 305 consecutive autopsy cases in Algeria]. / Mort subite de l'adulte : données de 305 cas d'autopsies consécutives en Algérie.

BACKGROUND-AIMS: Sudden death in a young adult who showed no prodrome or complaint during his lifetime is a tragedy. The death often remains unexplained by doctors and is often the subject of a judicial investigation following which an autopsy is ordered. Our study joins several studies around the world, where the results have linked sudden death in adults to a cardiac origin. METHODS: Through a series of 305 autopsies carried out in the forensic medicine department of the Frantz Fanon hospital in the city of Bejaia in Algeria over a period of two years, 57 cases corresponded to unexplained sudden deaths, i.e. an incidence of 3 cases per 100,000 inhabitants per year. RESULTS: Sudden death was of cardiac origin in 50.8% of cases (N=28). Two epidemiologic profiles emerge in our study: the first is that of a man aged between 50 and 60 years of age, with several deleterious lifestyle habits (in particular smoking) with a cardiovascular history, previously followed by a cardiologist, who died suddenly out-of-hospital, from ischemic heart disease. The second is that of a young adult under 40 years of age, of average build, with no particular medical history, having not previously consulted a cardiologist, who died suddenly of hypertrophic cardiomyopathy. CONCLUSIONS: In many instances, we observed major anatomical lesion, which had not motivated any prior medical consultation either with a general practitioner or with a cardiologist.

Transcriptomic sex differences in postmortem brain samples from patients with psychiatric disorders.

Many psychiatric disorders exhibit sex differences, but the underlying mechanisms remain poorly understood. We analyzed transcriptomics data from 2160 postmortem adult prefrontal cortex brain samples from the PsychENCODE consortium in a sex-stratified study design. We compared transcriptomics data of postmortem brain samples from patients with schizophrenia (SCZ), bipolar disorder (BD), and autism spectrum disorder (ASD) with transcriptomics data of postmortem control brains from individuals without a known history of psychiatric disease. We found that brain samples from females with SCZ, BD, and ASD showed a higher burden of transcriptomic dysfunction than did brain samples from males with these disorders. This observation was supported by the larger number of differentially expressed genes (DEGs) and a greater magnitude of gene expression changes observed in female versus male brain specimens. In addition, female patient brain samples showed greater overall connectivity dysfunction, defined by a higher proportion of gene coexpression modules with connectivity changes and higher connectivity burden, indicating a greater degree of gene coexpression variability. We identified several gene coexpression modules enriched in sex-biased DEGs and identified genes from a genome-wide association study that were involved in immune and synaptic functions across different brain cell types. We found a number of genes as hubs within these modules, including those encoding SCN2A, FGF14, and C3. Our results suggest that in the context of psychiatric diseases, males and females exhibit different degrees of transcriptomic dysfunction and implicate immune and synaptic-related pathways in these sex differences.

Usefulness of minimally invasive autopsy in the diagnosis of arboviruses to increase the sensitivity of the Epidemiological Surveillance System in Ceará, Brazil.

OBJECTIVE: To create a protocol for performing minimally invasive autopsies (MIA) in detecting deaths from arboviruses and report preliminary data from its application in Ceará state, Brazil. METHODS: Training was provided to medical pathologists on MIA. RESULTS: A protocol was established for performing MIA, defining criteria for sample collection, storage methods, and diagnoses to be carried out according to the type of biological sample; 43 MIAs were performed in three months. Of these, 21 (48.8%) arrived at the Death Verification Service (SVO) with arboviruses as a diagnostic hypothesis, and seven (16.3%) were confirmed (six chikungunya cases and one dengue case); cases of COVID-19 (n = 9), tuberculosis (n = 5), meningitis (n = 4), cryptococcosis (n = 1), Creutzfeldt-Jakob disease (n = 1), breast cancer (n = 1), and human rabies (n = 1) were also confirmed. CONCLUSION: The protocol implemented enabled identification of a larger number of suspected arbovirus-related deaths, as well as confirmation of other diseases of interest for surveillance. MAIN RESULTS: A protocol was developed to perform minimally invasive autopsies (MIAs) in Death Verification Services (SVO), capable of expanding the system's capacity to identify a greater number of deaths suspected to be due to arboviruses. IMPLICATIONS FOR SERVICES: The experience suggests that in-service trained health professionals are able to perform MIA, and that use of this technique in SVOs has been shown to be capable of increasing the system's sensitivity in detecting deaths of interest to public health. PERSPECTIVES: Trained professionals will be able to collect biological material in hospitals, through MIA, in cases of interest for health surveillance and when family members do not allow a complete conventional autopsy to be performed.

Peri-mortem rigidity in a fatal case of severe salicylate poisoning.

INTRODUCTION: There has been a previous case report of peri-arrest muscle rigidity in the setting of severe salicylate poisoning (serum salicylate concentration 1,500 mg/L), described as paratonia or rapid rigor mortis. We present an image of rapid rigor mortis in another fatal salicylate poisoning. CASE SUMMARY: We report a 42-year-old male with severe salicylate poisoning (peak salicylate concentration 1,600 mg/L). During the peri-arrest period, the patient developed isotonic flexion of the upper and lower extremities, the clinical signs of rapid-occurring rigor mortis. Despite resuscitative efforts, the patient died. IMAGE: Our patient is exhibiting peri-arrest rigidity in the upper extremities. DISCUSSION: Peri-mortem rigidity is due to depletion of adenosine triphosphate. Severe salicylate poisoning causes uncoupling of oxidative phosphorylation which prevents the production of adenosine triphosphate, which is required to release myosin from actin to allow the muscle to relax. A limitation of our report is that we did not definitively exclude other uncouplers of oxidative phosphorylation, such as 2,4-dinitrophenol. However, the history of aspirin ingestion was provided by the patient and corroborated by his mother, and it was confirmed by measurement of his salicylate concentration. CONCLUSION: We hypothesize that in our patient, rapid-occurring rigor mortis likely resulted from depletion of adenosine triphosphate. This occurred as a result of uncoupling of oxidative phosphorylation in the mitochondria from severe salicylate poisoning, as adenosine triphosphate is required for muscle relaxation.

Misclassification of causes of death among a small all-autopsied group of former nuclear workers: Death certificates vs. autopsy reports.

The U.S. Transuranium and Uranium Registries performs autopsies on each of its deceased Registrants as a part of its mission to follow up occupationally-exposed individuals. This provides a unique opportunity to explore death certificate misclassification errors, and the factors that influence them, among this small population of former nuclear workers. Underlying causes of death from death certificates and autopsy reports were coded using the 10th revision of the International Classification of Diseases (ICD-10). These codes were then used to quantify misclassification rates among 268 individuals for whom both full autopsy reports and death certificates with legible underlying causes of death were available. When underlying causes of death were compared between death certificates and autopsy reports, death certificates correctly identified the underlying cause of death's ICD-10 disease chapter in 74.6% of cases. The remaining 25.4% of misclassified cases resulted in over-classification rates that ranged from 1.2% for external causes of mortality to 12.2% for circulatory disease, and under-classification rates that ranged from 7.7% for external causes of mortality to 47.4% for respiratory disease. Neoplasms had generally lower misclassification rates with 4.3% over-classification and 13.3% under-classification. A logistic regression revealed that the odds of a match were 2.8 times higher when clinical history was mentioned on the autopsy report than when it was not. Similarly, the odds of a match were 3.4 times higher when death certificates were completed using autopsy findings than when autopsy findings were not used. This analysis excluded cases where it could not be determined if autopsy findings were used to complete death certificates. The findings of this study are useful to investigate the impact of death certificate misclassification errors on radiation risk estimates and, therefore, improve the reliability of epidemiological studies.

Postmortem metabolomics: influence of time since death on the level of endogenous compounds in human femoral blood. Necessary to be considered in metabolome study planning?

INTRODUCTION: The (un)targeted analysis of endogenous compounds has gained interest in the field of forensic postmortem investigations. The blood metabolome is influenced by many factors, and postmortem specimens are considered particularly challenging due to unpredictable decomposition processes. OBJECTIVES: This study aimed to systematically investigate the influence of the time since death on endogenous compounds and its relevance in designing postmortem metabolome studies. METHODS: Femoral blood samples of 427 authentic postmortem cases, were collected at two time points after death (854 samples in total; t1: admission to the institute, 1.3-290 h; t2: autopsy, 11-478 h; median ∆t = 71 h). All samples were analyzed using an untargeted metabolome approach, and peak areas were determined for 38 compounds (acylcarnitines, amino acids, phospholipids, and others). Differences between t2 and t1 were assessed by Wilcoxon signed-ranked test (p < 0.05). Moreover, all samples (n = 854) were binned into time groups (6 h, 12 h, or 24 h intervals) and compared by Kruskal-Wallis/Dunn's multiple comparison tests (p < 0.05 each) to investigate the effect of the estimated time since death. RESULTS: Except for serine, threonine, and PC 34:1, all tested analytes revealed statistically significant changes between t1 and t2 (highest median increase 166%). Unpaired analysis of all 854 blood samples in-between groups indicated similar results. Significant differences were typically observed between blood samples collected within the first and later than 48 h after death, respectively. CONCLUSIONS: To improve the consistency of comprehensive data evaluation in postmortem metabolome studies, it seems advisable to only include specimens collected within the first 2 days after death.

Estimation of cause-specific mortality in Rakai, Uganda, using verbal autopsy 1999-2019.

BACKGROUND: There are scant data on the causes of adult deaths in sub-Saharan Africa. We estimated the level and trends in adult mortality, overall and by different causes, in rural Rakai, Uganda, by age, sex, and HIV status. OBJECTIVES: To estimate and analyse adult cause-specific mortality trends in Rakai, Uganda. METHODOLOGY: Mortality information by cause, age, sex, and HIV status was recorded in the Rakai Community Cohort study using verbal autopsy interviews, HIV serosurveys, and residency data. We estimated the average number of years lived in adulthood. Using demographic decomposition methods, we estimated the contribution of each cause of death to adult mortality based on the average number of years lived in adulthood. RESULTS: Between 1999 and 2019, 63082 adults (15-60 years) were censused, with 1670 deaths registered. Of these, 1656 (99.2%) had completed cause of death data from verbal autopsy. The crude adult death rate was 5.60 (95% confidence interval (CI): 5.33-5.87) per 1000 person-years of observation (pyo). The crude death rate decreased from 11.41 (95% CI: 10.61-12.28) to 3.27 (95% CI: 2.89-3.68) per 1000 pyo between 1999-2004 and 2015-2019. The average number of years lived in adulthood increased in people living with HIV and decreased in HIV-negative individuals between 2000 and 2019. Communicable diseases, primarily HIV and Malaria, had the biggest decreases, which improved the average number of years lived by approximately extra 12 years of life in females and 6 years in males. There were increases in deaths due to non-communicable diseases and external causes, which reduced the average number of years lived in adulthood by 2.0 years and 1.5 years in females and males, respectively. CONCLUSION: There has been a significant decline in overall mortality from 1999 to 2019, with the greatest decline seen in people living with HIV since the availability of antiretroviral therapy in 2004. By 2020, the predominant causes of death among females were non-communicable diseases, with external causes of death dominating in males.

Main findings: There are significant declines in mortality in people living with HIV. However, mortality in HIV-negative people increased due to non-communicable diseases in females, and injuries and external causes of death among males.Added knowledge: In this HIV-endemic area, decreasing adult mortality has been documented over the last 20 years. This paper benchmarks the changes in cause-specific mortality in this area.Global health impact for policy action: As in many African countries, more effort is needed to reduce mortality for non-communicable diseases, injuries, and external causes of death as these seem to have been neglected.

Accuracy of the Verbal Autopsy questionnaire in the diagnosis of COVID-19 deaths in a Brazilian capital.

The Verbal Autopsy (VA) is a questionnaire about the circumstances surrounding a death. It was widely used in Brazil to assist in postmortem diagnoses and investigate excess mortality during the Coronavirus Disease 2019 (COVID-19) pandemic. This study aimed to determine the accuracy of investigating acute respiratory distress syndrome (ARDS) using VA. This is a cross-sectional study with prospective data collected from January 2020 to August 2021 at the Death Verification Service of Sao Luis city, Brazil. VA was performed for suspected COVID-19 deaths, and one day of the week was randomly chosen to collect samples from patients without suspected COVID-19. Two swabs were collected after death and subjected to reverse transcription-polymerase chain reaction (RT-PCR) for SARS-CoV-2 detection. Of the 250 cases included, the VA questionnaire identified COVID-19-related ARDS in 67.2% (52.98% were positive for COVID-19). The sensitivity of the VA questionnaire was 0.53 (0.45-0.61), the specificity was 0.75 (0.64-0.84), the positive predictive value was 0.81 (0.72-0.88), and the negative predictive value was 0.44 (0.36-0.53). The VA had a lower-than-expected accuracy for detecting COVID-19 deaths; however, because it is an easily accessible and cost-effective tool, it can be combined with more accurate methods to improve its performance.

Molecular Autopsy With Banked Cord Blood Reveals Brugada Syndrome in Past Sudden Death Case.

Molecular autopsy has recently been gaining attention as a means of postmortem diagnosis; however, it is usually performed using the victim's blood sample at the time of death. Here, we report the first case of a deceased infant with Brugada syndrome whose diagnosis was made with banked cord blood. A seemingly healthy 1-year-old male infant collapsed while having a fever; this collapse was witnessed by his mother. Despite cardiopulmonary resuscitation, he died of ventricular fibrillation. No abnormalities of cardiac structure were identified on autopsy. Genomic samples were not stored at the time because of a lack of suspicion for familial arrhythmia. Five years later, his sister showed Brugada electrocardiogram pattern while febrile from Kawasaki disease. Their father showed a spontaneous type 1 Brugada electrocardiogram pattern. A heterozygous SCN5A p.R893C variant was found by genetic testing in the proband's father and sister. Furthermore, the proband's genetic testing was performed using his banked cord blood, which identified the same variant. Family history of Brugada syndrome with an SCN5A-R893C variant and clinical evidence led to a postmortem diagnosis of Brugada syndrome in the proband. Identification of this variant in this case later contributed to verifying SCN5A-R893C as a pathogenic variant through data accumulation. Banked cord blood may prove useful for conducting molecular autopsies in previously undiagnosed cases of sudden death in which genomic samples were not stored.

Post-mortem detection of hemoplasmas (hemotropic Mycoplasma spp.) in South American fur seal (Arctocephalus australis) sampled in Rio Grande do Sul State, southern Brazil.

Hemotropic mycoplasmas are bacteria that attaches to erythrocytes surface, which some species presents zoonotic concerns. In the suborder Pinnipedia, genera Otaria and Arctocephalus are prominent in Brazil. This study investigated the occurrence of hemoplasmas in Arctocephalus sp. and Otaria flavescens found dead along the coast of a Southern Brazilian State. DNA from 135 spleen samples were extracted and subjected to conventional PCR protocols, targeting the 16 S rRNA and 23 S rRNA gene. Three (2.22 %) Arctocephalus australis were positive in the 16 S rRNA gene, and no samples amplified in the 23 S rRNA gene. Samples from this study clustered with Zalophus californianus and Arctocephalus tropicalis mycoplasmas on a Bayesian phylogenetic analysis. Genetic diversity analysis suggested distinct genotypes, indicating A. australis as a new host for hemoplasma, and also a potential putative novel hemoplasma genotype. These findings raises future awareness for pinnipeds conservation, and adds Mycoplasma spp. to be taken into consideration when clinically evaluating rescued animals.

Parvalbumin interneurons in human ventromedial prefrontal cortex: a comprehensive post-mortem study of myelination and perineuronal nets in neurotypical individuals and depressed suicides with and without a history of child abuse.

Cortical parvalbumin interneurons (PV+) are major regulators of excitatory/inhibitory information processing, and their maturation is associated with the opening of developmental critical periods (CP). Recent studies reveal that cortical PV+ axons are myelinated, and that myelination along with perineuronal net (PNN) maturation around PV+ cells is associated with the closures of CP. Although PV+ interneurons are susceptible to early-life stress, their relationship between their myelination and PNN coverage remains unexplored. This study compared the fine features of PV+ interneurons in well-characterized human post-mortem ventromedial prefrontal cortex samples (n = 31) from depressed suicides with or without a history of child abuse (CA) and matched controls. In healthy controls, 81% of all sampled PV+ interneurons displayed a myelinated axon, while a subset (66%) of these cells also displayed a PNN, proposing a relationship between both attributes. Intriguingly, a 3-fold increase in the proportion of unmyelinated PV+ interneurons with a PNN was observed in CA victims, along with greater PV-immunofluorescence intensity in myelinated PV+ cells with a PNN. This study, which is the first to provide normative data on myelination and PNNs around PV+ interneurons in human neocortex, sheds further light on the cellular and molecular consequences of early-life adversity on cortical PV+ interneurons.

Disentangling the heterogeneity of multiple sclerosis through identification of independent neuropathological dimensions.

Multiple sclerosis (MS) is a heterogeneous neurological disorder with regards to clinical presentation and pathophysiology. Here, we investigated the heterogeneity of MS by performing an exploratory factor analysis on quantitative and qualitative neuropathology data collected for 226 MS donors in the Netherlands Brain Bank autopsy cohort. Three promising dimensions were identified and subsequently validated with clinical, neuropathological, and genetic data. Dimension 1 ranged from a predominance of remyelinated and inactive lesions to extensive pathological changes, higher proportions of active and mixed lesions, and foamy microglia morphology. This pattern was positively correlated with more severe disease, the presence of B and T cells, and neuroaxonal damage. Scoring high on dimension 2 was associated with active lesions, reactive sites, and the presence of nodules. These donors had less severe disease, a specific pattern of cortical lesions, and MS risk variants in the human leukocyte antigen region, the latter indicating a connection between disease onset and this neuropathological dimension. Donors scoring high on dimension 3 showed increased lesional pathology with relatively more mixed and inactive lesions and ramified microglia morphology. This pattern was associated with longer disease duration, subpial cortical lesions, less involvement of the adaptive immune system, and less axonal damage. Taken together, the three dimensions may represent (1) demyelination and immune cell activity associated with pathological and clinical progression, (2) microglia (re)activity and possibly lesion initiation, and (3) loss of lesion activity and scar formation. Our findings highlight that a thorough understanding of the interplay between multiple pathological characteristics is crucial to understand the heterogeneity of MS pathology, as well as its association with genetic predictors and disease outcomes. The scores of donors on the dimensions can serve as an important starting point for further disentanglement of MS heterogeneity and translation into observations and interventions in living cohorts with MS.