Accuracy and validity of determined cause of death and manner of death following forensic autopsy prosection.

AIMS: The purpose of this study is to evaluate the accuracy and validity of the determination of cause of death (COD) and manner of death (MOD) at the completion of the forensic autopsy prosection. METHODS: We analysed 952 autopsy cases conducted from 2019 to 2020 and compared every patient's COD, other significant contributing factors to death (OSC), and MOD after prosection to their COD, OSC and MOD after completion of the final autopsy report. RESULTS: We found that 83% of cases (790 patients) did not have an unexpected change and 17% of cases (162 patients) exhibited a true change in their final diagnosis; the relationship between age and changes in COD and MOD was significant. CONCLUSIONS: Our findings indicate that in the majority of forensic autopsy cases, medical professionals can reasonably complete death certification after the autopsy prosection. In addition to improving the accuracy of COD and MOD, advances in this field will enhance timely decedent affairs management, timely investigations of crimes and timely closure to families who have lost loved ones. We recommend implementing combined interventional education and consultation with expert pathologists, and a well-followed structured method of death classification as the best course of practice.

Forensic Neuropathologic Phenotypes of Fungal Central Nervous System Infections: A Case Series.

ABSTRACT: Fungal infections of the central nervous system (FI-CNS) are life-threatening infections that most commonly affect immunocompromised individuals, but immunocompetent individuals may also be infected. Although FI-CNS are relatively rare, the prevalence of FI-CNS is on the rise because of the increasing number of transplant recipients, human immunodeficiency virus-infected individuals, and use of immunosuppressive therapies. Most cases of FI-CNS originate from outside the central nervous system. The etiologic fungi can be classified into 3 fungal groups: molds, dimorphic fungi, and yeasts. The clinical presentation of FI-CNS is highly variable and may be difficult to diagnose premortem. We present a case series of 3 patients, each infected by 1 representative species from each of the 3 fungal groups (Aspergillus species, Blastomyces species, Candida species) to illustrate different neuropathologic phenotypes of FI-CNS. All 3 patients had no history of immunodeficiency and were not suspected to have FI-CNS until they were diagnosed at autopsy. Fungal infections of the central nervous system are often fatal due to delayed diagnosis and diagnostic testing. Awareness of such poly-phenotypic manifestations of FI-CNS will be helpful in reducing delayed diagnosis. It is important for clinicians to include FI-CNS on the differential diagnosis when radiographic findings are nonspecific.

Autopsy Cardiac Troponin I Plasma Levels Can Be Elevated in Myocardial Infarction Type 3: A Proposal to Modify the Definition of Myocardial Infarction Type 3.

AIMS: The definition of myocardial infarction (MI) type 3 does not include the possible elevation of postmortem biomarkers if measured at autopsy. We determined postmortem cardiac troponin I (cTnI) levels in plasma samples obtained at autopsy in patients who died from MI type 3 to determine whether cTnI plasma levels may be elevated. METHODS AND RESULTS: Using a chemiluminescent microparticle immunoassay system, we determined postmortem cTnI plasma levels at autopsy performed within 24 hours of death in every decedent who died from MI type 3, confirmed by an autopsy. Over 2 years, autopsy confirmed 52 decedents who died from MI type 3 due to coronary atherosclerotic disease. The age range and mean age were 40 to 78 and 60.6 years, respectively, 38 (73%) men and 14 (27%) women. Ten percent of the decedents exhibited postmortem cTnI plasma levels that were within the normal reference levels (0.01-0.30 ng/mL). Ninety percent of the decedents exhibited elevated cTnI plasma levels at autopsy, which ranged from 0.31 to greater than 4400 ng/mL. Sixty-nine percent of our decedents showed severe/significant (75%-100%) luminal occlusion in 2 or 3 major coronary arteries. CONCLUSIONS: If cTnI plasma levels are measured in autopsy blood samples after sudden and unexpected death due to MI type 3, highly elevated cTnI plasma levels may be detected. We propose that the current MI type 3 definition be slightly modified to include the possible elevation of cTnI plasma levels if measured at autopsy in the immediate postmortem period.

FDDNP-PET Tau Brain Protein Binding Patterns in Military Personnel with Suspected Chronic Traumatic Encephalopathy1.

BACKGROUND: Our group has shown that in vivo tau brain binding patterns from FDDNP-PET scans in retired professional football players with suspected chronic traumatic encephalopathy differ from those of tau and amyloid aggregate binding observed in Alzheimer's disease (AD) patients and cognitively-intact controls. OBJECTIVE: To compare these findings with those from military personnel with histories of mild traumatic brain injury(mTBI). METHODS: FDDNP-PET brain scans were compared among 7 military personnel and 15 retired players with mTBI histories and cognitive and/or mood symptoms, 24 AD patients, and 28 cognitively-intact controls. Nonparametric ANCOVAs with Tukey-Kramer adjusted post-hoc comparisons were used to test for significant differences in regional FDDNP binding among subject groups. RESULTS: FDDNP brain binding was higher in military personnel compared to controls in the amygdala, midbrain, thalamus, pons, frontal and anterior and posterior cingulate regions (p < 0.01-0.0001). Binding patterns in the military personnel were similar to those of the players except for the amygdala and striatum (binding higher in players; p = 0.02-0.003). Compared with the AD group, the military personnel showed higher binding in the midbrain (p = 0.0008) and pons (p = 0.002) and lower binding in the medial temporal, lateral temporal, and parietal regions (all p = 0.02). CONCLUSION: This first study of in vivo tau and amyloid brain signals in military personnel with histories of mTBI shows binding patterns similar to those of retired football players and distinct from the binding patterns in AD and normal aging, suggesting the potential value of FDDNP-PET for early detection and treatment monitoring in varied at-risk populations.

Postmortem Autopsy-Confirmation of Antemortem [F-18]FDDNP-PET Scans in a Football Player With Chronic Traumatic Encephalopathy.

Currently, only presumptive diagnosis of chronic traumatic encephalopathy (CTE) can be made in living patients. We present a modality that may be instrumental to the definitive diagnosis of CTE in living patients based on brain autopsy confirmation of [F-18]FDDNP-PET findings in an American football player with CTE. [F-18]FDDNP-PET imaging was performed 52 mo before the subject's death. Relative distribution volume parametric images and binding values were determined for cortical and subcortical regions of interest. Upon death, the brain was examined to identify the topographic distribution of neurodegenerative changes. Correlation between neuropathology and [F-18]FDDNP-PET binding patterns was performed using Spearman rank-order correlation. Mood, behavioral, motor, and cognitive changes were consistent with chronic traumatic myeloencephalopathy with a 22-yr lifetime risk exposure to American football. There were tau, amyloid, and TDP-43 neuropathological substrates in the brain with a differential topographically selective distribution. [F-18]FDDNP-PET binding levels correlated with brain tau deposition (rs = 0.59, P = .02), with highest relative distribution volumes in the parasagittal and paraventricular regions of the brain and the brain stem. No correlation with amyloid or TDP-43 deposition was observed. [F-18]FDDNP-PET signals may be consistent with neuropathological patterns of tau deposition in CTE, involving areas that receive the maximal shearing, angular-rotational acceleration-deceleration forces in American football players, consistent with distinctive and differential topographic vulnerability and selectivity of CTE beyond brain cortices, also involving midbrain and limbic areas. Future studies are warranted to determine whether differential and selective [F-18]FDDNP-PET may be useful in establishing a diagnosis of CTE in at-risk patients.

Role of Tau Acetylation in Alzheimer's Disease and Chronic Traumatic Encephalopathy: The Way Forward for Successful Treatment.

Progressive neurodegenerative diseases plague millions of individuals both in the United States and across the world. The current pathology of progressive neurodegenerative tauopathies, such as Alzheimer's disease (AD), Pick's disease, frontotemporal dementia (FTD), and progressive supranuclear palsy, primarily revolves around phosphorylation and hyperphosphorylation of the tau protein. However, more recent evidence suggests acetylation of tau protein at lysine 280 may be a critical step in molecular pathology of these neurodegenerative diseases prior to the tau hyperphosphorylation. Secondary injury cascades such as oxidative stress, endoplasmic reticulum stress, and neuroinflammation contribute to lasting damage within the brain and can be induced by a number of different risk factors. These injury cascades funnel into a common pathway of early tau acetylation, which may serve as the catalyst for progressive degeneration. The post translational modification of tau can result in production of toxic oligomers, contributing to reduced solubility as well as aggregation and formation of neurofibrillary tangles, the hallmark of AD pathology. Chronic Traumatic Encephalopathy (CTE), caused by repetitive brain trauma is also associated with a hyperphosphorylation of tau. We postulated acetylation of tau at lysine 280 in CTE disease could be present prior to the hyperphosphorylation and tested this hypothesis in CTE pathologic specimens. We also tested for ac-tau 280 in early stage Alzheimer's disease (Braak stage 1). Histopathological examination using the ac tau 280 antibody was performed in three Alzheimer's cases and three CTE patients. Presence of ac-tau 280 was confirmed in all cases at early sites of disease manifestation. These findings suggest that tau acetylation may precede tau phosphorylation and could be the first "triggering" event leading to neuronal loss. To the best of our knowledge, this is the first study to identify acetylation of the tau protein in CTE. Prevention of tau acetylation could possibly serve as a novel target for stopping neurodegeneration before it fully begins. In this study, we highlight what is known about tau acetylation and neurodegeneration.

Autopsy-proven Mirtazapine Withdrawal-induced Mania/Hypomania Associated with Sudden Death.

Manic episodes induced by antidepressant withdrawal are rarely reported. Mirtazapine is a tetracyclic, piperazinoazepine compound and is a noradrenergic, adrenergic, serotonergic, histaminergic, and muscarinic-antagonist antidepressant that is used for the treatment of major depression and other psychiatric illnesses. There are several reported cases of manic/hypomanic episodes induced by mirtazapine withdrawal based on suspected clinical symptoms that were not confirmed by autopsy and toxicology. We present the first reported case of mirtazapine withdrawal-induced mania/hypomania associated with sudden death and confirmed by autopsy and toxicology. Our patient was a 26-year-old male who had been diagnosed with schizophreniform disorder, borderline intellectual functioning, polysubstance abuse, mild mental retardation, and attention deficit hyperactive disorder. He took only mirtazapine in the final and terminal weeks of his life and stopped taking mirtazapine 4 days before his death. He exhibited a sudden manic/hypomanic episode and died during a physical altercation during this episode. A full autopsy with comprehensive toxicologic analysis of his body fluids and tissues was performed. Autopsy revealed that he died from blunt force trauma of the head, neck, and trunk with extremely low and markedly subtherapeutic levels of mirtazapine and desmethylmirtazapine in the blood (mirtazapine: 0.005 mg/L; desmethylmirtazapine 0.011 mg/L). Advanced selective radioligand and neurochemical assays for density and affinity-binding parameters of dopamine transporter and heat shock protein 70 did not reveal any evidence of excited delirium or autonomic hyperactivity state. We recommend that toxicologic analysis of blood for antidepressants should become routine parts of autopsy protocols for the investigation of sudden death following terminal manic/hypomanic episodes for further elucidation of mania/hypomania induced by antidepressant withdrawal.

Progressive Focal Gray Matter Volume Loss in a Former High School Football Player: A Possible Magnetic Resonance Imaging Volumetric Signature for Chronic Traumatic Encephalopathy.

Here a case is presented of a 51-year-old former high school football player with multiple concussions, including one episode with loss of consciousness. The patient experienced 6 years of cognitive and mood decline, and his wife corroborated increasing memory loss, attentional difficulties, and depressed mood without suicidal ideation. He had been unable to maintain full-time employment because of progressive decline. Based on his presentation, he had been previously diagnosed with attention deficit hyperactivity disorder and bipolar disorder, type II. Neuropsychological tests indicated domain-specific cognitive impairment, and longitudinal volumetric magnetic resonance imaging (MRI) of the brain showed progressive brainstem, diencephalic, and frontal lobe atrophy. This regional volume loss correlated with the increased signal seen on tau and amyloid imaging (FDDNP-PET scan) of a separate case of suspected chronic traumatic encephalopathy (CTE). Visual assessment of the MRI also showed evidence of old petechial hemorrhages in the frontal and temporal-parietal lobe white matter. This case raises the possibility of distinct quantitative and visual brain MRI findings in suspected CTE.

Perfusion Neuroimaging Abnormalities Alone Distinguish National Football League Players from a Healthy Population.

BACKGROUND: National Football League (NFL) players are exposed to multiple head collisions during their careers. Increasing awareness of the adverse long-term effects of repetitive head trauma has raised substantial concern among players, medical professionals, and the general public. OBJECTIVE: To determine whether low perfusion in specific brain regions on neuroimaging can accurately separate professional football players from healthy controls. METHOD: A cohort of retired and current NFL players (n = 161) were recruited in a longitudinal study starting in 2009 with ongoing interval follow up. A healthy control group (n = 124) was separately recruited for comparison. Assessments included medical examinations, neuropsychological tests, and perfusion neuroimaging with single photon emission computed tomography (SPECT). Perfusion estimates of each scan were quantified using a standard atlas. We hypothesized that hypoperfusion particularly in the orbital frontal, anterior cingulate, anterior temporal, hippocampal, amygdala, insular, caudate, superior/mid occipital, and cerebellar sub-regions alone would reliably separate controls from NFL players. Cerebral perfusion differences were calculated using a one-way ANOVA and diagnostic separation was determined with discriminant and automatic linear regression predictive models. RESULTS: NFL players showed lower cerebral perfusion on average (p < 0.01) in 36 brain regions. The discriminant analysis subsequently distinguished NFL players from controls with 90% sensitivity, 86% specificity, and 94% accuracy (95% CI 95-99). Automatic linear modeling achieved similar results. Inclusion of age and clinical co-morbidities did not improve diagnostic classification. CONCLUSION: Specific brain regions commonly damaged in traumatic brain injury show abnormally low perfusion on SPECT in professional NFL players. These same regions alone can distinguish this group from healthy subjects with high diagnostic accuracy. This study carries implications for the neurological safety of NFL players.

Endoplasmic reticulum stress implicated in chronic traumatic encephalopathy.

OBJECTIVE: Chronic traumatic encephalopathy is a progressive neurodegenerative disease characterized by neurofibrillary tau tangles following repetitive neurotrauma. The underlying mechanism linking traumatic brain injury to chronic traumatic encephalopathy has not been elucidated. The authors investigate the role of endoplasmic reticulum stress as a link between acute neurotrauma and chronic neurodegeneration. METHODS: The authors used pharmacological, biochemical, and behavioral tools to assess the role of endoplasmic reticulum stress in linking acute repetitive traumatic brain injury to the development of chronic neurodegeneration. Data from the authors' clinically relevant and validated rodent blast model were compared with those obtained from postmortem human chronic traumatic encephalopathy specimens from a National Football League player and World Wrestling Entertainment wrestler. RESULTS: The results demonstrated strong correlation of endoplasmic reticulum stress activation with subsequent tau hyperphosphorylation. Various endoplasmic reticulum stress markers were increased in human chronic traumatic encephalopathy specimens, and the endoplasmic reticulum stress response was associated with an increase in the tau kinase, glycogen synthase kinase-3ß. Docosahexaenoic acid, an endoplasmic reticulum stress inhibitor, improved cognitive performance in the rat model 3 weeks after repetitive blast exposure. The data showed that docosahexaenoic acid administration substantially reduced tau hyperphosphorylation (t = 4.111, p < 0.05), improved cognition (t = 6.532, p < 0.001), and inhibited C/EBP homology protein activation (t = 5.631, p < 0.01). Additionally the data showed, for the first time, that endoplasmic reticulum stress is involved in the pathophysiology of chronic traumatic encephalopathy. CONCLUSIONS: Docosahexaenoic acid therefore warrants further investigation as a potential therapeutic agent for the prevention of chronic traumatic encephalopathy.

In vivo characterization of chronic traumatic encephalopathy using [F-18]FDDNP PET brain imaging.

Chronic traumatic encephalopathy (CTE) is an acquired primary tauopathy with a variety of cognitive, behavioral, and motor symptoms linked to cumulative brain damage sustained from single, episodic, or repetitive traumatic brain injury (TBI). No definitive clinical diagnosis for this condition exists. In this work, we used [F-18]FDDNP PET to detect brain patterns of neuropathology distribution in retired professional American football players with suspected CTE (n = 14) and compared results with those of cognitively intact controls (n = 28) and patients with Alzheimer's dementia (AD) (n = 24), a disease that has been cognitively associated with CTE. [F-18]FDDNP PET imaging results in the retired players suggested the presence of neuropathological patterns consistent with models of concussion wherein brainstem white matter tracts undergo early axonal damage and cumulative axonal injuries along subcortical, limbic, and cortical brain circuitries supporting mood, emotions, and behavior. This deposition pattern is distinctively different from the progressive pattern of neuropathology [paired helical filament (PHF)-tau and amyloid-ß] in AD, which typically begins in the medial temporal lobe progressing along the cortical default mode network, with no or minimal involvement of subcortical structures. This particular [F-18]FDDNP PET imaging pattern in cases of suspected CTE also is primarily consistent with PHF-tau distribution observed at autopsy in subjects with a history of mild TBI and autopsy-confirmed diagnosis of CTE.

Chronic traumatic encephalopathy.

Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative syndrome, which is caused by single, episodic, or repetitive blunt force impacts to the head and transfer of acceleration-deceleration forces to the brain. CTE presents clinically as a composite syndrome of mood disorders and behavioral and cognitive impairment, with or without sensorimotor impairment. Symptoms of CTE may begin with persistent symptoms of acute traumatic brain injury (TBI) following a documented episode of brain trauma or after a latent period that may range from days to weeks to months and years, up to 40 years following a documented episode of brain trauma or cessation of repetitive TBI. Posttraumatic encephalopathy is distinct from CTE, can be comorbid with CTE, and is a clinicopathologic syndrome induced by focal and/or diffuse, gross and/or microscopic destruction of brain tissue following brain trauma. The brain of a CTE sufferer may appear grossly unremarkable, but shows microscopic evidence of primary and secondary proteinopathies. The primary proteinopathy of CTE is tauopathy, while secondary proteinopathies may include, but are not limited to, amyloidopathy and TDP proteinopathy. Reported prevalence rates of CTE in cohorts exposed to TBI ranges from 3 to 80% across age groups.

Role of subconcussion in repetitive mild traumatic brain injury.

Research now suggests that head impacts commonly occur during contact sports in which visible signs or symptoms of neurological dysfunction may not develop despite those impacts having the potential for neurological injury. Recent biophysics studies utilizing helmet accelerometers have indicated that athletes at the collegiate and high school levels sustain a surprisingly high number of head impacts ranging from several hundred to well over 1000 during the course of a season. The associated cumulative impact burdens over the course of a career are equally important. Clinical studies have also identified athletes with no readily observable symptoms but who exhibit functional impairment as measured by neuropsychological testing and functional MRI. Such findings have been corroborated by diffusion tensor imaging studies demonstrating axonal injury in asymptomatic athletes at the end of a season. Recent autopsy data have shown that there are subsets of athletes in contact sports who do not have a history of known or identified concussions but nonetheless have neurodegenerative pathology consistent with chronic traumatic encephalopathy. Finally, emerging laboratory data have demonstrated significant axonal injury, blood-brain barrier permeability, and evidence of neuroinflammation, all in the absence of behavioral changes. Such data suggest that subconcussive level impacts can lead to significant neurological alterations, especially if the blows are repetitive. The authors propose "subconcussion" as a significant emerging concept requiring thorough consideration of the potential role it plays in accruing sufficient anatomical and/or physiological damage in athletes and military personnel, such that the effects of these injuries are clinically expressed either contemporaneously or later in life.

PET scanning of brain tau in retired national football league players: preliminary findings.

OBJECTIVE: Mild traumatic brain injury due to contact sports may cause chronic behavioral, mood, and cognitive disturbances associated with pathological deposition of tau protein found at brain autopsy. To explore whether brain tau deposits can be detected in living retired players, we used positron emission tomography (PET) scans after intravenous injections of 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP). METHODS: Five retired National Football League players (age range: 45 to 73 years) with histories of mood and cognitive symptoms received neuropsychiatric evaluations and FDDNP-PET. PET signals in subcortical (caudate, putamen, thalamus, subthalamus, midbrain, cerebellar white matter) and cortical (amygdala, frontal, parietal, posterior cingulate, medial and lateral temporal) regions were compared with those of five male controls of comparable age, education, and body mass index. RESULTS: FDDNP signals were higher in players compared with controls in all subcortical regions and the amygdala, areas that produce tau deposits following trauma. CONCLUSIONS: The small sample size and lack of autopsy confirmation warrant larger, more definitive studies, but if future research confirms these initial findings, FDDNP-PET may offer a means for premorbid identification of neurodegeneration in contact-sports athletes.