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{{short description|Atypical form of encephalitis (sleeping sickness)}}
{{SI}}
{{Multiple issues|
{{Infobox medical condition
{{Expert needed|Medicine|talk=Edits of this day|reason=all sections need attention, generally, with regard to differentiating EL from [[Postencephalitic parkinsonism]], and the Treatments section, specifically, need revision by a medical expert, based on secondary sources |date=December 2015}}
{{more medical citations needed|date=December 2015}}
}}
{{Infobox medical condition (new)
| name = Encephalitis lethargica
| name = Encephalitis lethargica
| synonyms = Nellysa disease; Economo's disease
| image = [[File:Economo1918h.PNG|250px]]
| image = Economo1918h.PNG
| caption = Drawing of a patient with encephalitis lethargica
| caption = Brain tissue of a monkey infected with E. lethargica as seen under a microscope (from von Economo's ''Die Encephalitis lethargica'' (1918))
| prognosis = Variable, can lead to [[chronic illness]]
| differential =
| frequency = Rare
| prevention =
| deaths = Historical epidemic in the 1920s
| treatment =
| medication =
| prognosis =
| frequency = Unknown
| deaths =
}}
}}
'''Encephalitis lethargica''' is an atypical form of [[encephalitis]]. Also known as "'''sleeping sickness'''" or "'''sleepy sickness'''" (distinct from [[tsetse fly]]-transmitted [[African trypanosomiasis|sleeping sickness]]), it was first described in 1917 by the neurologist [[Constantin von Economo]]<ref>{{WhoNamedIt|synd|3356|Economo's disease}}</ref><ref>{{cite journal |first=K. |last=von Economo |journal=Wiener klinische Wochenschrift |trans-journal=Vienna clinical weekly |date=May 10, 1917 |volume=30 |pages=581–585 |language=de |title=Die Encephalitis lethargica. |location=Leipzig and Vienna |publisher=Franz Deuticke 1918}}</ref> and the pathologist [[Jean-René Cruchet]].<ref>{{cite journal |last1=Cruchet |first1=R |last2= Moutier |first2=J |last3= Calmettes |first3=A |title= Quarante cas d'encéphalomyélite subaiguë |trans-title=Forty cases of (subacute) encephalitis lethargica |journal=Bull Soc Med Hôp |location=Paris |year=1917 |volume=41 |pages=614–6 |language=fr}}</ref>
The disease attacks the brain, leaving some victims in a statue-like condition, speechless and motionless.<ref name=Dale_2004>{{cite journal |author=Dale, Russell C. |author2=Church, Andrew J. |author3=Surtees, Robert A.H. |author4=Lees, Andrew J. |author5=Adcock, Jane E. |author6=Harding, Brian |author7=Neville, Brian G. R. |author8=Giovannoni, Gavin | title = Encephalitis Lethargica Syndrome: 20 New Cases and Evidence of Basal Ganglia Autoimmunity | journal = Brain | volume = 127 | issue = 1 | pages = 21–33 | year = 2004 | url = http://brain.oxfordjournals.org/content/127/1/21.full | pmid = 14570817 | doi = 10.1093/brain/awh008 | accessdate = 8 December 2015 | doi-access = free }}{{primary-source-inline|date=December 2015}}{{better source|date=December 2015}}</ref> Between 1915 and 1926,<ref>{{DorlandsDict|nine/000952335|Encephalitis lethargica}}</ref> an [[epidemic]] of encephalitis lethargica spread around the world. Nearly five million people were affected, a third of whom died in the acute stages. Many of those who survived never returned to their pre-existing "aliveness".<blockquote>They would be conscious and aware – yet not fully awake; they would sit motionless and speechless all day in their chairs, totally lacking energy, impetus, initiative, motive, appetite, affect or desire; they registered what went on about them without active attention, and with profound indifference. They neither conveyed nor felt the feeling of life; they were as insubstantial as ghosts, and as passive as zombies.<ref>''[[Awakenings (book)|Awakenings]]'', [[Oliver Sacks]], p. 14</ref></blockquote>No recurrence of the epidemic has since been reported, though isolated cases continue to occur.<ref name=Stryker_1925>{{cite journal | author = Stryker Sue B. | title = Encephalitis lethargica: the behavior residuals | journal = Training School Bulletin | volume = 22 | issue = 1925 | pages = 152–7}}</ref><ref name=Reid_2001>{{cite journal |author1=Reid, A.H. |author2=McCall, S. |author3=Henry, J.M. |author4=Taubenberger, J.K. | title = Experimenting on the Past: The Enigma of von Economo's Encephalitis Lethargica | journal = J. Neuropathol. Exp. Neurol. | volume = 60 | issue = 7 | pages = 663–670 | year = 2001 | pmid = 11444794 | doi = 10.1093/jnen/60.7.663| doi-access = free }}</ref><!-- So how *many* died? -->
==Signs and symptoms==
Encephalitis lethargica is characterized by high [[fever]], sore throat, [[headache]], [[lethargy]], [[Diplopia|double vision]], delayed physical and mental response, [[sleep inversion]] and [[catatonia]].<ref name=Dale_2004/><ref>{{Cite journal|last=KOCH|first=CHRISTOF|date=March–April 2016|title=Sleep without End|url=|journal=Scientific American Mind|volume=27|issue=2|pages=22–25|doi=10.1038/scientificamericanmind0316-22}}</ref> In severe cases, patients may enter a [[coma]]-like state ([[akinetic mutism]]).{{citation needed|date=December 2015}} Patients may also experience abnormal [[Human eye|eye]] movements ("oculogyric crises"),<ref name="pmid16200538">{{cite journal |author1=Vilensky, J.A. |author2=Goetz, C.G. |author3=Gilman, S. |title=Movement Disorders Associated with Encephalitis Lethargica: A Video Compilation | journal = Mov. Disord. | volume=21 | issue=1, January | pages=1–8 | year = 2006 |pmid=16200538 |doi=10.1002/mds.20722}}</ref> [[Parkinsonism]], upper body weakness, muscular pains, tremors, neck rigidity, and behavioral changes including [[psychosis]].{{citation needed|date=December 2015}} [[Klazomania]] (a vocal [[tic]]) is sometimes present.<ref name=Jankovic>{{cite journal |author1=Jankovic, J. |author2=Mejia, N.I. |title= Tics Associated with Other Disorders | journal = Adv. Neurol. | year=2006 | volume=99 |pages=61–8 |pmid= 16536352}}</ref>
==Cause==
[[Image:Encephalitis-livre.png|thumb|Encephalitis lethargica. Its [[sequelae]] and treatment – Constantin Von Economo, 1931: front page]]
The causes of encephalitis lethargica are uncertain.<ref name="pmid18569452">{{cite journal |author1=McCall, S. |author2=Vilensky, J.A. |author3=Gilman, S. |author4=Taubenberger, J.K. |title=The Relationship Between Encephalitis Lethargica and Influenza: A Critical Analysis |journal=[[J. Neurovirol.]] | volume=14 |issue=3, May | pages=177–185 | year = 2008 | pmid=18569452 | doi=10.1080/13550280801995445 |pmc=2778472}}</ref>
Some studies have explored its origins in an [[autoimmune]] response,<ref name=Dale_2004/> and, separately or in relation to an immune response, links to pathologies of infectious disease — viral and bacterial,<ref name=Dale_2004/> e.g., in the case of influenza, where a link with encephalitis is clear.<ref name="Haeman">{{Cite journal|doi=10.1073/pnas.0900096106 |author1=Haeman, Jang |author2=Boltz, D. |author3=Sturm-Ramirez, K. |author4=Shepherd, K.R. |author5=Jiao, Y. |author6=Webster, R. |author7=Smeyne, Richard J. |title=Highly Pathogenic H5N1 Influenza Virus Can Enter the Central Nervous System and Induce Neuroinflammation and Neurodegeneration | accessdate=8 December 2015 |year=2009 |url=http://www.pnas.org/content/early/2009/08/07/0900096106.full.pdf+html | journal=[[Proceedings of the National Academy of Sciences]] |volume=106 |pages=14063–14068 | pmid=19667183 | issue=33, August 10 | pmc=2729020 }}</ref> Postencephalitic [[parkinsonism]] was clearly documented to have followed an outbreak of encephalitis lethargica following the [[1918 influenza pandemic]]; evidence for viral causation of the Parkinson's symptoms is circumstantial ([[epidemiology|epidemiologic]], and finding influenza [[antigen]]s in encephalitis lethargica patients), while evidence arguing against this cause is of the [[Argument from ignorance#Distinguishing absence of evidence from evidence of absence|negative sort]] (e.g., lack of [[RNA virus|viral RNA]] in postencephalitic parkinsonian brain material).<ref name="Haeman"/>
In reviewing the relationship between influenza and encephalitis lethargica (EL), McCall and coworkers conclude, as of 2008, that while "the case against influenza [is] less decisive than currently perceived… there is little direct evidence supporting influenza in the etiology of EL," and that "[a]lmost 100 years after the EL epidemic, its etiology remains enigmatic."<ref name=Reid_2001/> Hence, while opinions on the relationship of encephalitis lethargica to influenza remain divided, the preponderance of literature appears skeptical.<ref name=Reid_2001/><ref name="pmid17675021">{{cite journal |author1=Vilensky, J.A. |author2=Foley, P. |author3=Gilman, S. | year = 2007 |title=Children and Encephalitis Lethargica: A Historical Review |journal=[[Pediatr. Neurol.]] |volume=37 |issue=2, August |pages=79–84 | pmid=17675021 |doi=10.1016/j.pediatrneurol.2007.04.012 |url=http://www.pedneur.com/article/S0887-8994(07)00194-4/abstract | access-date = 8 December 2015 }}</ref>
German neurologist Felix Stern, who examined hundreds of encephalitis lethargica patients during the 1920s, pointed out that the encephalitis lethargica typically evolved over time. The early symptom would be dominated by sleepiness or wakefulness. A second symptom would lead to an [[oculogyric crisis]]. The third symptom would be recovery, followed by a Parkinson-like symptom. If patients of Stern followed this course of disease, he diagnosed them with encephalitis lethargica. Stern suspected encephalitis lethargica to be close to polio without evidence. Nevertheless, he experimented with the [[Antiserum|convalescent serum]] of survivors of the first acute symptom. He vaccinated patients with early stage symptoms and told them that it might be successful. Stern is author of the 1920s definitive book ''Die Epidemische Encephalitis'' (1920 and 2nd ed. 1928). Stern was driven to suicide during [[the Holocaust]] by the German state, his research forgotten.<ref>{{cite web|title=Auf der Spur der Schlaf-Epidemie|periodical=Spektrum.de|url=https://www.spektrum.de/news/felix-stern-der-arzt-der-das-geheimnis-der-encephalitis-lethargica-lueften-wollte/1618214|accessdate=2019-01-28|date=2019-01-25|language=de}}</ref>
In 2010, in a substantial Oxford University Press compendium reviewing the historic and contemporary views on EL, its editor, Joel Vilensky of the [[Indiana University School of Medicine]], quotes Pool, writing in 1930, who states, "we must confess that etiology is still obscure, the causative agent still unknown, the pathological riddle still unsolved…", and goes on to offer the following conclusion, as of that publication date:{{quote|Does the present volume solve the "riddle" of EL, which… has been referred to as the greatest medical mystery of the 20th century? Unfortunately, no: but inroads are certainly made here pertaining to diagnosis, pathology, and even treatment."<ref>{{cite book |author1=Vilensky, J.A. |author2=Gilman, S. | year = 2010 | chapter = Introduction | title = Encephalitis Lethargica: During and After the Epidemic | editor = Vilensky, Joel A. |
location = Oxford, ENG | publisher = Oxford University Press | isbn = 978-0190452209 | chapter-url = https://books.google.com/books?isbn=019045220X | access-date = 8 December 2015 | pages = 3–7, esp. 6f }}</ref>}}Subsequent to publication of this compendium, an [[enterovirus]] was discovered in encephalitis lethargica cases from the epidemic.<ref>{{Cite journal|last=Dourmashkin|first=Robert R.|last2=Dunn|first2=Glynis|last3=Castano|first3=Victor|last4=McCall|first4=Sherman A.|date=2012-01-01|title=Evidence for an enterovirus as the cause of encephalitis lethargica|journal=[[BMC Infectious Diseases]]|volume=12|pages=136|doi=10.1186/1471-2334-12-136|issn=1471-2334|pmc=3448500|pmid=22715890}}</ref> In 2012, [[Oliver Sacks]] acknowledged this virus as the probable cause of the disease.<ref>Letter from Oliver Sacks to Professor Joel A. Vilensky, 9 Sept 2012.</ref> Other sources have suggested ''[[Diplococcus]]'' as a cause.<ref>{{cite news|url=http://news.bbc.co.uk/1/hi/health/3930727.stm|title=Mystery of the forgotten plague|date=27 July 2004|publisher=|via=news.bbc.co.uk}}</ref>
== History ==
=== Occurrences ===
Retrospective diagnosis tentatively suggests numerous accounts of encephalitis lethargica throughout history:
* In 1580, Europe was swept by a serious febrile and lethargic illness, which led to [[Parkinsonism|Parkinsonian]] and other neurological sequelae.<ref name=":1">{{Cite book|last=Sacks|first=Oliver|title=Awakenings|date=1990|publisher=HarperPerennial|isbn=0-06-097368-4|edition=1st Vintage Books|location=New York|pages=319–321|oclc=21910570}}</ref>
* In 1673–1675, a similar serious epidemic occurred in [[London]], which [[Thomas Sydenham]] described as "febris comatosa."<ref name=":1" />
* In 1695, a 20-year-old woman in [[Germany]] experienced [[Oculogyric crisis|oculogyric crises]], [[Parkinsonism]], [[diplopia]], [[strabismus]], and other symptoms following an attack of [[Somnolence|somnolent]] [[brain fever]], as described by Dr. [[Albrecht family|Albrecht]] of [[Hildesheim]].<ref name=":1" />
* In 1712–1713, a severe epidemic of ''Schlafkrankheit'' (encephalitis lethargica) occurred in [[Tübingen]], [[Germany]], followed in many cases by persistent slowness of movement and lack of initiative ([[aboulia]]).<ref name=":1" />
* Between 1750 and 1800, [[France]] and [[Germany]] experienced minor epidemics of "coma somnolentum" with Parkinsonian features, includig hyperkinetic [[Hiccup|hiccough]], [[myoclonus]], [[chorea]], and [[Tic|tics]].
* Between 1848 and 1882, [[Paris]]-based neurologist [[Jean-Martin Charcot]] documented many isolated cases of juvenile [[Parkinsonism]], associated with [[diplopia]], [[Oculogyric crisis|oculogyria]], tachypnoea ([[hyperventilation]]), retropulsion, [[Tic|tics]], and obsessional disorders, which were almost certainly post-encephalitic in origin.<ref name=":1" />
* In 1890 in [[Italy]], following the influenza epidemic of 1889–1890, a severe epidemic of somnolent illnesses (nicknamed the "''Nona"'') appeared. For the few survivors of the ''Nona,'' Parkinsonism and other sequelae developed in almost all cases.<ref name=":1" />
* Between 1915 and 1926, a world-wide encephalitis lethargica pandemic occurred, impacting nearly 5 million people and killing an estimated 1.6 million people.
=== The encephalitis lethargica pandemic of 1915–1926 ===
In the winter of 1916–1917, a "new" illness suddenly appeared in [[Vienna]] and other cities, and rapidly spread world-wide over the next three years. Earlier reports appeared throughout Europe as early as the winter of 1915–1916, but communication about the disease was slow and chaotic, given the varied manifestation of symptoms and difficulties disseminating information in wartime.<ref name=":0">{{Cite book|last=Sacks|first=Oliver|title=Awakenings|publisher=HarperPerennial|year=1990|isbn=0-375-70405-1|edition=1st Vintage Books|location=New York|pages=12–19|oclc=21910570}}</ref> Until [[Constantin von Economo]] identified a unique pattern of damage among the brains of deceased patients and introduced the unifying name ''encephalitis lethargica,'' reports of the protean disease came in under a range of names: [[botulism]], toxic [[ophthalmoplegia]], epidemic stupor, epidemic lethargic encephalitis, acute [[polioencephalitis]], [[Heine-Medin disease]], bulbar paralysis, [[hystero-epilepsy]], acute dementia, and sometimes just "an obscure disease with cerebral symptoms."<ref name=":0" /> Just ten days before von Economo's breakthrough in Vienna, [[Jean-René Cruchet]] described forty cases of "subacute encephalomyelitis" in France.<ref name=":0" />
In the ten years that the pandemic raged, nearly five million people's lives were taken or ravaged. Encephalitis lethargica assumed its most virulent form between October 1918 and January 1919. The pandemic disappeared in 1927 as abruptly and mysteriously as it first appeared.<ref name=":0" /> The great encephalitis pandemic coincided with the [[Spanish flu|1918 influenza pandemic]], and it is likely that the influenza virus potentiated the effects of the encephalitis virus or lowered resistance to it in a catastrophic way.<ref name=":0" />
=== Aftermath of the pandemic (postencephalitic syndromes) ===
Many surviving patients of the 1915–1926 encephalitis lethargica [[pandemic]] seemed to make a complete recovery and return to their normal lives. However, the majority of survivors subsequently developed neurological or psychiatric disorders, often after years or decades of seemingly perfect health. Post-encephalitic syndromes varied widely: sometimes they proceeded rapidly, leading to profound disability or death; sometimes very slowly; sometimes they progressed to a certain point and then stayed at this point for years or decades; and sometimes, following their initial onslaught, they remitted and disappeared.<ref>{{Cite book|last=Sacks|first=Oliver|title=Awakenings|publisher=HarperPerennial|year=1990|isbn=0-375-70405-1|edition=1st Vintage Books|location=New York|pages=20–21|oclc=21910570}}</ref> [[Postencephalitic parkinsonism|Postencephaltic Parkinsonism]] is perhaps the most widely recognized of such syndromes.
== Diagnosis ==
There have been several proposed diagnostic criteria for encephalitis lethargica. One, which has been widely accepted, includes an acute or subacute encephalitic illness where all other known causes of encephalitis have been excluded. Another diagnostic criterion, suggested more recently, says that the diagnosis of encephalitis lethargica "may be considered if the patient’s condition cannot be attributed to any other known neurological condition and that they show the following signs: [[Influenza]]-like signs; [[hypersomnolence]] ([[hypersomnia]]), wakeability, [[ophthalmoplegia]] (paralysis of the muscles that control the movement of the eye), and psychiatric changes."<ref>{{cite web|url=https://www.encephalitis.info/encephalitis-lethargica|title=Encephalitis Lethargica|last1=Easton|first1=Ava|website=The Encephalitis Society|accessdate=27 December 2017}}</ref>
== Treatment ==
[[Image:Levodopa.png|thumb|[[L-DOPA]]]]
Modern treatment approaches to encephalitis lethargica include immunomodulating therapies, and treatments to remediate specific symptoms.<ref>{{cite journal |author1=Lopez-Alberola, R |author2=Georgiou, M |author3=Sfakianakis, G.N. |author4=Singer, C. |author5=Papapetropoulos, S. | year = 2009 | journal = J. Neurol. | volume = 256 | issue = 3, March | pages = 396–404 | doi = 10.1007/s00415-009-0074-4 | title = Contemporary Encephalitis Lethargica: Phenotype, Laboratory Findings and Treatment Outcomes | pmid=19412724}}{{primary-source-inline|date=December 2015}}</ref>{{primary-source-inline|date=December 2015}}
There is little evidence so far of a consistent effective treatment for the initial stages, though some patients given [[steroids]] have seen improvement.<ref name=Blunt_1997>{{cite journal |author1=Blunt, S.B. |author2=Lane, R.J. |author3=Turjanski, N. |author4=Perkin, G.D. | title = Clinical Features and Management of Two Cases of Encephalitis Lethargica | journal = Mov. Disord. | volume = 12 | issue = 3 | pages = 354–9 | year = 1997 | pmid = 9159730 | doi = 10.1002/mds.870120314}}</ref>{{primary-source-inline|date=December 2015}} The disease becomes progressive, with evidence of brain damage similar to [[Parkinson's disease]].<ref>Kohnstamm P (1934). Über die Beteiligung der beiden Schichten der Substantia nigra am Prozeß der Encephalitis epidemica. ''J Psychol Neurol'' '''46'''(1): 22–37.{{primary-source-inline|date=December 2015}}{{better source|date=December 2015}}</ref>{{primary-source-inline|date=December 2015}}{{update after|2015|12|9}}
Treatment is then symptomatic. [[Levodopa]] (<small>L</small>-DOPA) and other anti-Parkinson drugs often produce dramatic responses; however, most people given <small>L</small>-DOPA experience improvements that are short lived.<ref>{{Cite web|url=https://www.ninds.nih.gov/Disorders/All-Disorders/Encephalitis-Lethargica-Information-Page|title=Encephalitis Lethargica Information Page|date=August 9, 2018|website=National Institute of Neurological Disorders and Stroke}}</ref><ref>{{cite book|last1=Sacks|first1=Oliver|title=Awakenings|date=1973|publisher=Duckworth & Co.|isbn=978-0-375-70405-5}}</ref>
==Notable cases==
Notable cases include:
* Muriel "Kit" Richardson (née Hewitt), first wife of actor Sir [[Ralph Richardson]], died of the condition in October 1942, having first shown symptoms in 1927–28.
* There is speculation that [[Adolf Hitler]] may have had encephalitis lethargica when he was a young adult (in addition to the more substantial case for Parkinsonism in his later years).<ref>{{cite journal|title= Adolf Hitler Had Post-Encephalitic Parkinsonism | journal= Parkinsonism Relat Disord. |date= April 1996 |volume= 2| number= 2| pages= 95–103| last= Lieberman |first= A| pmid=18591024 | doi=10.1016/1353-8020(96)00005-3}}</ref><ref>{{ cite journal |author1=Boettcher, L.B. |author2=Bonney, P.A. |author3=Smitherman A.D. |author4=Sughrue, M.E. | year = 2015 | journal = Neurosurg Focus | volume = 39 | issue = 1, July | page = E8 | doi = 10.3171/2015.4.FOCUS1563 | title = Hitler's Parkinsonism | pmid=26126407| doi-access = free }}</ref><ref>{{cite journal|title= Understanding the Influence of Parkinson's Disease on Adolf Hitler's Decision-Making During World War II | journal= World Neurosurg. | year = 2015 | authors = Gupta, R; Kim, C; Agarwal, N; Lieber, B & Monaco, E.A. | pmid=26093359 | volume = 84 | issue = 5, November | pages= 1447–1452 | doi= 10.1016/j.wneu.2015.06.014}}</ref><ref>{{cite journal | author = Rosen, Denis | year = 2010 | title = Review: "Asleep: the Forgotten Epidemic That Remains One of Medicine's Greatest Mysteries" [Molly Caldwell Crosby| journal= J. Clin. Sleep Med. | volume= 6 | number= 3, 15 June | page= 299 | pmc= 2883045 | doi = 10.5664/jcsm.27831 }}</ref>
* [[Mervyn Peake]] (1911–1968), author of the [[Gormenghast (series)|''Gormenghast'']] books, began his decline towards death which was initially attributed to encephalitis lethargica with Parkinson's disease-like symptoms, although others have later suggested his decline in health and eventual death may have been due to [[Lewy body dementia]].<ref name="dlb">{{cite journal|author=Demetrios J. Sahlas|year=2003|title=Dementia With Lewy Bodies and the Neurobehavioral Decline of Mervyn Peake|journal=Arch. Neurol.|volume=60|issue=6|pages=889–92|doi=10.1001/archneur.60.6.889|pmid=12810496|doi-access=free}}</ref><ref>{{Cite book|url=http://download.audible.com/product_related_docs/BK_NAXO_000663.pdf|title=Publisher's Liner Notes on Mervyn Peake for 'Titus Alone'|last=McMillan|first=Roy|last2=Peake|date=20 July 2011|editor-last=Butcher Sara|website=Audible.com|publisher=Naxos Audiobooks|location=Germany|page=7|language=English|type=PDF, Liner Notes|format=Liner Notes/ Reference Guide for Abridged Audiobook of Titus Alone|orig-year=1959|publication-date=20 July 2011|isbn=978-184-379-542-1|access-date=2 May 2018|quote=But the plays were not the financial winners he had hoped for, and he suffered another nervous breakdown in 1957. This led to the more evident display of the symptoms of a type of Parkinson’s Disease which, alongside the effects of encephalitis lethargica that he contracted in childhood, was slowly to kill him over more than a decade.|edition=Abridged, Audio}}</ref>
* [[Rosita Renard]] (1894–1949), Chilean pianist, contemporary of [[Claudio Arrau]] and student of [[Martin Krause]].
* Those described in the book [[Awakenings (book)|Awakenings]] by the British neurologist [[Oliver Sacks]].
==References==
{{Reflist}}
==Further reading==
* {{cite journal | author = Sacks O | year = 1983 | title = The origin of 'Awakenings' | url = | journal = Br. Med. J. (Clin. Res. Ed.) | volume = 287 | issue = 6409| pages = 1968–1969 | doi=10.1136/bmj.287.6409.1968| pmid = 6418286 | pmc = 1550182 }}
* {{cite journal |author1=Reid, A.H. |author2=McCall, S. |author3=Henry, J.M. |author4=Taubenberger, J.K. | title = Experimenting on the Past: The Enigma of von Economo's Encephalitis Lethargica | journal = J. Neuropathol. Exp. Neurol. | volume = 60 | issue = 7 | pages = 663–670 | year = 2001 | pmid = 11444794 | doi = 10.1093/jnen/60.7.663| doi-access = free }}
* {{cite journal |author1=Vilensky, J.A. |author2=Foley, P. |author3=Gilman, S. | year = 2007 |title=Children and Encephalitis Lethargica: A Historical Review |journal=Pediatr. Neurol. |volume=37 |issue=2, August |pages=79–84 | pmid=17675021 |doi=10.1016/j.pediatrneurol.2007.04.012}}
* {{cite book | year = 2010 | editor = Vilensky, Joel A. | title = Encephalitis Lethargica: During and After the Epidemic | location = Oxford, ENG | publisher = Oxford University Press | isbn = 978-0190452209 | url = https://books.google.com/books?isbn=019045220X | access-date = 8 December 2015 }}
* {{cite book | author = Crosby, Molly Caldwell | year = 2010 | title = 'Asleep: The Forgotten Epidemic that Remains One of Medicine's Greatest Mysteries | location = New York, NY, USA | publisher = Penguin/Berkley }} Describes the history of the disease, and the epidemic of the 1920s.
== External links ==
{{Medical resources
| DiseasesDB = 32498
| ICD10 = {{ICD10|A|85|8|a|80}}
| ICD9 = {{ICD9|049.8}}
| ICDO =
| OMIM =
| MedlinePlus =
| eMedicineSubj =
| eMedicineTopic =
| MeshID =
}}
* [http://www.ninds.nih.gov/health_and_medical/disorders/encephalitis_lethargica.htm National Institute of Neurological Disorders and Stroke]
* [http://news.bbc.co.uk/1/hi/health/3930727.stm Mystery of the Forgotten Plague]: BBC news item about the tracing of the infectious agent in encephalitis lethargica
{{Viral diseases}}
{{CNS diseases of the nervous system}}
[[Category:Encephalitis]]
'''Encephalitis lethargica''', also known as '''sleepy sickness''', is a rare and mysterious neurological disease that was first identified in the early 20th century. It is characterized by high fever, headache, double vision, delayed physical and mental response, and lethargy. The disease can lead to a state of coma-like sleep, and in some cases, it can result in long-term neurological damage or death.
[[Category:Unsolved problems in neuroscience]]
==History==
[[Category:Ailments of unknown cause]]
The first recorded outbreak of encephalitis lethargica occurred in 1916, and it spread worldwide, affecting millions of people. The disease reached epidemic proportions between 1917 and 1928. The cause of the epidemic remains unknown, and it disappeared as mysteriously as it appeared.
[[Category:Viral infections of the central nervous system]]
==Symptoms==
The symptoms of encephalitis lethargica can vary widely among individuals. Common symptoms include:
* High fever
* Severe headache
* Lethargy and prolonged sleepiness
* Double vision
* Delayed physical and mental responses
* Muscle pain and weakness
* Behavioral changes
In severe cases, patients may enter a coma-like state, and some may experience [[Parkinsonism]] or other long-term neurological sequelae.
==Pathophysiology==
The exact cause of encephalitis lethargica is unknown, but it is believed to be related to an [[autoimmune]] response triggered by an infection. Some researchers have suggested a link to the [[influenza]] virus, but this has not been conclusively proven. The disease primarily affects the [[brain]], particularly the [[midbrain]] and [[diencephalon]], leading to the characteristic symptoms.
==Diagnosis==
Diagnosis of encephalitis lethargica is challenging due to its rarity and the lack of specific diagnostic tests. It is primarily based on clinical presentation and the exclusion of other conditions. [[Magnetic resonance imaging]] (MRI) and [[computed tomography]] (CT) scans may be used to rule out other causes of encephalitis.
==Treatment==
There is no specific treatment for encephalitis lethargica. Management focuses on alleviating symptoms and providing supportive care. [[Corticosteroids]] and other immunosuppressive therapies may be used to reduce inflammation. In cases with Parkinsonian symptoms, [[dopaminergic]] medications may be beneficial.
==Prognosis==
The prognosis for encephalitis lethargica varies. Some patients recover fully, while others may experience long-term neurological complications. The disease can be fatal in severe cases.
Encephalitis lethargica, also known as sleepy sickness, is a rare and mysterious neurological disease that was first identified in the early 20th century. It is characterized by high fever, headache, double vision, delayed physical and mental response, and lethargy. The disease can lead to a state of coma-like sleep, and in some cases, it can result in long-term neurological damage or death.
The first recorded outbreak of encephalitis lethargica occurred in 1916, and it spread worldwide, affecting millions of people. The disease reached epidemic proportions between 1917 and 1928. The cause of the epidemic remains unknown, and it disappeared as mysteriously as it appeared.
The exact cause of encephalitis lethargica is unknown, but it is believed to be related to an autoimmune response triggered by an infection. Some researchers have suggested a link to the influenza virus, but this has not been conclusively proven. The disease primarily affects the brain, particularly the midbrain and diencephalon, leading to the characteristic symptoms.
Diagnosis of encephalitis lethargica is challenging due to its rarity and the lack of specific diagnostic tests. It is primarily based on clinical presentation and the exclusion of other conditions. Magnetic resonance imaging (MRI) and computed tomography (CT) scans may be used to rule out other causes of encephalitis.
There is no specific treatment for encephalitis lethargica. Management focuses on alleviating symptoms and providing supportive care. Corticosteroids and other immunosuppressive therapies may be used to reduce inflammation. In cases with Parkinsonian symptoms, dopaminergic medications may be beneficial.
The prognosis for encephalitis lethargica varies. Some patients recover fully, while others may experience long-term neurological complications. The disease can be fatal in severe cases.
