Encephalitis lethargica: could this disease be recognised if the epidemic recurred?

On Respiratory Crisis and Other Respiratory Curiosities in the Aftermath of Encephalitis Lethargica: "Like Asthma"

Pandemics in the early 20^th century (and now with SARS-CoV-2) have been dominated by respiratory viruses damaging lungs. Less is known about abnormal respiratory patterns from brain inflammation. One of the first descriptions of respiratory rhythm abnormalities was seen with an acute attack of epidemic encephalitis (encephalitis lethargica), and reports appeared soon after the original description in 1921. We reviewed these ill-remembered disorders of the respiration rate, respiratory patterns and respiratory "tics." Most commonly, dysregulations occurred during the phase when ocular signs appeared. The early symptoms were an unrelenting tachypnea without air hunger and an inspiratory hold (fixés en inspiration forcée). Initially regarded as "hysterical" in nature, the later bizarre disorders of respiration were considered equally serious with attacks of gasping, panting, puffing, inspiratory breath holding, coughs, giggles, sighing, grunting, and moaning. These respiratory disorders were seen exclusively as part of a parkinsonian syndrome. Most remarkably, these attacks could be provoked by oxygen administration.These respiratory abnormalities with encephalitis lethargica are not well remembered. One purpose of recalling these episodes is to call attention to central causes of respiratory illness even in pandemics with respiratory viruses.

Tics in patients with encephalitis

BACKGROUND

Movement disorders have been described in the context of different types of encephalitis. Among hyperkinetic manifestations, tics have sporadically been reported in cases of encephalitis resulting from a range of aetiologies.

OBJECTIVE

This review aimed to assess the prevalence and characteristics of tics in patients with encephalitis.

METHODS

We conducted a systematic literature review of original studies on the major scientific databases, according to the standards outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

In addition to the established association between tics and encephalitis lethargica, our literature search identified reports of tics in patients with immune-mediated pathologies (including autoimmune encephalitides affecting the N-methyl-D-aspartate receptor, voltage-gated potassium channels, and glycine receptors) and infective processes (ranging from relatively common viral pathogens, such as herpes simplex, to prions, as in Creutzfeldt-Jakob disease). Tics were most commonly reported in the post-encephalitic period and involvement of the basal ganglia was frequently observed.

DISCUSSION

The association of new-onset tics and encephalitis, in the background of other neuropsychiatric abnormalities, has practical implications, potentially improving the detection of encephalitis based on clinical features. Future research should focus on the categorisation and treatment of hyperkinetic movement disorders associated with encephalitis.

Part of the Covid19 puzzle: Acute parkinsonism

Parkinsonism developed owing to viruses is one of the important causes of secondary parkinsonism. After the Spanish flu pandemic, the increase in the number of parkinsonian cases in the long term has drawn attention on the relationship between viruses and parkinsonism. For this reason, the relationship between influenza and parkinsonism has been studied most. Nowadays in which we are experiencing the COVID-19 pandemic, scientists, based on the experiences gained from the Spanish flu pandemic, have drawn attention to the fact that the third wave of the pandemic might be parkinsonism. However, as we have reviewed in the literature, acute parkinsonism due to COVID-19 was not reported during this pandemic. Here, we present a case in which signs of acute parkinsonism developed on the 3rd day of the illness and neurological symptoms regressed with convalescent plasma treatment.

Global Consortium Study of Neurological Dysfunction in COVID-19 (GCS-NeuroCOVID): Study Design and Rationale

BACKGROUND

As the COVID-19 pandemic developed, reports of neurological dysfunctions spanning the central and peripheral nervous systems have emerged. The spectrum of acute neurological dysfunctions may implicate direct viral invasion, para-infectious complications, neurological manifestations of systemic diseases, or co-incident neurological dysfunction in the context of high SARS-CoV-2 prevalence. A rapid and pragmatic approach to understanding the prevalence, phenotypes, pathophysiology and prognostic implications of COVID-19 neurological syndromes is urgently needed.

METHODS

The Global Consortium to Study Neurological dysfunction in COVID-19 (GCS-NeuroCOVID), endorsed by the Neurocritical Care Society (NCS), was rapidly established to address this need in a tiered approach. Tier-1 consists of focused, pragmatic, low-cost, observational common data element (CDE) collection, which can be launched immediately at many sites in the first phase of this pandemic and is designed for expedited ethical board review with waiver-of-consent. Tier 2 consists of prospective functional and cognitive outcomes assessments with more detailed clinical, laboratory and radiographic data collection that would require informed consent. Tier 3 overlays Tiers 1 and 2 with experimental molecular, electrophysiology, pathology and imaging studies with longitudinal outcomes assessment and would require centers with specific resources. A multicenter pediatrics core has developed and launched a parallel study focusing on patients ages <18 years. Study sites are eligible for participation if they provide clinical care to COVID-19 patients and are able to conduct patient-oriented research under approval of an internal or global ethics committee. Hospitalized pediatric and adult patients with SARS-CoV-2 and with acute neurological signs or symptoms are eligible to participate. The primary study outcome is the overall prevalence of neurological complications among hospitalized COVID-19 patients, which will be calculated by pooled estimates of each neurological finding divided by the average census of COVID-19 positive patients over the study period. Secondary outcomes include: in-hospital, 30 and 90-day morality, discharge modified Rankin score, ventilator-free survival, ventilator days, discharge disposition, and hospital length of stay.

RESULTS

In a one-month period (3/27/20-4/27/20) the GCS-NeuroCOVID consortium was able to recruit 71 adult study sites, representing 17 countries and 5 continents and 34 pediatrics study sites.

CONCLUSIONS

This is one of the first large-scale global research collaboratives urgently assembled to evaluate acute neurological events in the context of a pandemic. The innovative and pragmatic tiered study approach has allowed for rapid recruitment and activation of numerous sites across the world-an approach essential to capture real-time critical neurological data to inform treatment strategies in this pandemic crisis.

Does the historical literature on encephalitis lethargica support a simple (direct) relationship with postencephalitic Parkinsonism?

This article and the subsequent one suggest that the currently accepted view of a simplistic (direct) relationship between encephalitis lethargica (EL) and postencephalitic Parkinsonism (PEP) is based on a incomplete evaluation of the epidemic period literature. In this article we provide a detailed analysis of the literature from the period that demonstrates that Parkinsonism was not initially part of acute EL symptomatology, that PEP was not typically the prevailing type of chronic EL and that oculogyric crises were never part of acute EL symptomatology and not initially associated with PEP. The second paper uses these finding, and also examines the clinical justifications for concluding that all patients with PEP had prior acute episodes of EL, to reevaluate the presumed direct etiologic relationship between EL and PEP.

Review: neuropathology of acute phase encephalitis lethargica: a review of cases from the epidemic period

INTRODUCTION

Encephalitis lethargica (EL), an epidemic disease of the early 20th century, has continued to be diagnosed sporadically since that time, including a report of 20 new cases in 2004. Many of the recent case reports state that the primary neuropathology of acute EL consists of inflammatory changes and lesions within the midbrain, basal ganglia and substantia nigra. However, the neuropathology of acute EL cases from the epidemic period was actually much more widespread.

METHODS

In order to characterize the neuropathology of acute phase EL, we developed a database of EL pathology based on 112 cases from the years 1915 to 1940, of which most died within 2 weeks of EL onset.

RESULTS

Our analysis revealed that cortical damage was prevalent in 75% of the 112 cases; damage to the meninges and brainstem occurred in approximately half of the cases; and the substantia nigra was damaged in only 13% of these acute cases. We also found that after 1921, damage to cranial nerve nuclei was not reported. An analysis of the neuropathology and clinical symptoms revealed little correlation.

CONCLUSIONS

Based on these findings, putative modern cases of acute EL with MRI/CT indicated lesions confined solely to the midbrain, brainstem, and/or basal ganglia should not be considered, consistent with that reported during epidemic period.

Encephalitis lethargica and the influenza virus. III. The influenza pandemic of 1918/19 and encephalitis lethargica: neuropathology and discussion

This is the second of two papers which critically examine the relationship between the 1918/19 influenza pandemic and encephalitis lethargica (EL). The role of influenza in the etiology of EL was vigorously debated until 1924. It is notable, however, that the unitarian camp were largely reactive in their argumentation; while the influenza skeptics provided detail descriptions of EL and the features they argued to be unique or at least unusual, influenza supporters focused on sequentially refuting the evidence of their opponents. The impression which emerges from this debate is that the individual features identified by the skeptics were not absolutely pathognomic for EL, but, on the other hand, their combination in one disorder had not previously been described for any other disease.

Was encephalitis lethargica a post-influenzal or some other phenomenon? Time to re-examine the problem

Encephalitis lethargica (EL) was first reported in 1917 in central Europe. It became epidemic in the winter of 1918/1919 concurrently with the pandemic of influenza, and by then had reached Russia and North America. It spread throughout the world in epidemic form, mainly in the succeeding winters, up to 1927. By then about 65 000 cases had been reported, although the true number worldwide can only be guessed at. EL mortality was about 30% in the acute stage, and similar during recurrences. Half of the survivors had persistent or recurrent neuro-psychiatric illness, with Parkinsonism a frequent end stage. Most contemporary observers attributed EL to a virus and some believed it was specifically a post-influenzal complication. The epidemiology of EL mostly points to an infective cause, e.g. a seasonal respiratory or gastrointestinal virus with infrequent encephalitic expression but the ability to persist, flare and progressively damage the brain. However, any link with the influenza virus strain of 1918/1919 remains hypothetical. The aetiological theories that have been applied to EL are reviewed and the question is raised whether broader laboratory investigation might now reveal a continuing low endemicity of EL and identify its cause.

A great American psychiatrist reconsidered. Commentary on "Neuropsychiatric sequelae of cerebral trauma in children", by Edward A. Strecker and Franklin G. Ebaugh

In a seminal article from the early twentieth century, a vivid picture was painted of the psychiatric outcomes of child head injury. Reading this now, the insights to be derived are considerable.

Viral parkinsonism

Parkinson's disease is a debilitating neurological disorder that affects 1-2% of the adult population over 55 years of age. For the vast majority of cases, the etiology of this disorder is unknown, although it is generally accepted that there is a genetic susceptibility to any number of environmental agents. One such agent may be viruses. It has been shown that numerous viruses can enter the nervous system, i.e. they are neurotropic, and induce a number of encephalopathies. One of the secondary consequences of these encephalopathies can be parkinsonism, that is both transient as well as permanent. One of the most highlighted and controversial cases of viral parkinsonism is that which followed the 1918 influenza outbreak and the subsequent induction of von Economo's encephalopathy. In this review, we discuss the neurological sequelae of infection by influenza virus as well as that of other viruses known to induce parkinsonism including Coxsackie, Japanese encephalitis B, St. Louis, West Nile and HIV viruses.

Children and encephalitis lethargica: a historical review

Between 1917 and the late 1920s, encephalitis lethargica was an epidemic and often lethal neurologic disease. In adults, it typically elicited severe somatic effects, and in particular, various forms of cranial nerve and motor dysfunction. In children, the psychiatric effects were often as severe as the physical consequences. Approximately one third of affected children underwent a rapid transformation from normal behavior to delinquency, often leading to institutionalization. Many neurologic and psychological theories were advanced to explain these severe behavioral changes, and the therapeutic approaches employed ranged from training in dedicated schools to frontal leucotomy. Whereas epidemiologic associations provide both positive and negative support for an etiologic relationship between encephalitis lethargica and the approximately contemporaneous "Spanish" influenza epidemic, previously unutilized data from children provide some of the strongest links between influenza and encephalitis lethargica. Encephalitis lethargica triggered behavioral changes in children that are not duplicated by any other neurologic condition, with the possible exception of traumatic brain injury. These unique behavioral abnormalities may provide the earliest clear indication of new encephalitis lethargica cases, whether alone or in concert with an influenza epidemic.