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Encephalitis lethargica

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  • Encephalitis lethargica

    Encephalitis lethargica
    Encephalitis lethargica

    Dr Trisha Macnair
    This mysterious illness, also known as sleeping sickness, can cause fever, headache, weakness and other symptoms, which can lead to a prolonged state of unconsciousness or to Parkinson's disease.

    The cause remains a mystery.
    What is it?

    Between 1917 and 1928 a puzzling illness swept around the world. Young people, especially women, seemed to be most vulnerable, although it affected people of all ages.

    Doctors named it encephalitis lethargica, which simply means 'inflammation of the brain that makes you tired'.

    Thousands of people were struck down and many survivors were left to battle difficult symptoms for years afterwards.

    Some thought it was caused by a virus, some confused it with the Spanish flu epidemic of the time, while others blamed weapons used in World War I. But scientists are still not clear what causes the condition.

    Although an epidemic of encephalitis lethargica hasn't recurred, occasional cases had been reported beforehand and are still sometimes seen. Some experts suggest it may be more common than we realise, but that many more minor cases go undiagnosed.

    Doctors in south-west England are trying to pin down exactly how common it is. You can see details at

    Many other names have been given to the condition or to diseases that appear to cause the same symptoms. These include Von Economo's disease, Cruchet's disease, Akureyri disease (after a similar epidemic in Iceland in 1948), benign myalgic encephalomyelitis and sleeping disease.


    The illness usually starts with a high fever, headache and sore throat

    The symptoms of encephalitis lethargica can be variable, but the illness usually starts with a high fever, headache and sore throat.

    Double vision, disturbance of eye movements, weakness of the upper body, tremors and strange movements, neck stiffness, intense muscle pains, a slowing of physical and mental response, drowsiness and lethargy soon follow.

    Unusual brain and nerve symptoms may occur, and the person's behaviour and personality may change too. Occasionally, they become psychotic with extremely disturbed thinking.

    Sometimes the illness is mistaken for epilepsy, hysteria or even drug or alcohol abuse.

    Long-term effects

    As the body shuts down, patients become increasingly sleepy and some may lose consciousness, slipping into a coma that can last months or even years.

    This is why the disease is sometimes known as sleeping sickness.
    Many died during the 1920s' epidemic, but modern medicine can help to keep people alive.

    The disease leaves a variety of problems that can cause prolonged disability

    However, the disease leaves a variety of problems that can cause prolonged disability. Most people recovering from encephalitis lethargica develop a form of Parkinson's disease, with typical symptoms of
    slowness, tremor and abnormal muscle movements called dystonia. As with Parkinson's there may be little facial movement, so although the person can hear, understand and is mentally fine, they don't appear to respond much to the world around them.

    These problems may develop as long as a year after recovery. There may also be problems with swallowing or vision, as well as long-term behavioural disorders. However, some people do manage to make a full recovery.


    Many people believe a virus or other type of infection may be to blame for encephalitis lethargica, but there's not yet good evidence of any particular organism.

    Some researchers have suggested it might be an auto-immune disease, where the body's immune system is triggered by a throat infection (perhaps with a streptococcus bacteria) to attack the nervous system.

    Research shows that areas of the brain called the mid-brain and basal ganglia become inflamed during the illness. But while anti-brain antibodies can be detected, no viruses have been found. This suggests the syndrome isn't caused by a virus directly entering and attacking the brain, so could it be that the body's own immune cells are attacking the nerve cells here?


    As long as the cause of encephalitis lethargica remains unknown, it's difficult to give specific treatment or prevent the disease. There's no cure for the condition. Instead, treatment is targeted at supporting the person through their illness and dealing with the symptoms as they occur.

    In the early stages, treatment in an intensive care unit may be necessary to keep the person breathing, fed and protected from other infections, especially if they're in a coma. Steroid drugs may help to reduce inflammation in the brain.

    Treatment in an intensive care unit may be necessary

    As the person recovers, physiotherapy, nutritional support and speech therapy may all help to speed them on the path back to normality. They may also need psychological support to deal with emotional and behavioural problems.


    The Sophie Cameron Trust
    Kelston House, College Road, Lansdown, Bath BA1 5RY
    Tel: 01225 424224

    This article was last medically reviewed by Dr Rob Hicks in December 2005.

  • #2
    Re: Encephalitis lethargica

    It may interest you & it is very recent. It is a suprise for me that encephalitis is mostly an unknown like that today in 2006.


    <dl class="PubmedArticle" id="dlPubmedArticle17109290"><dt class="head" id="head17109290">1: Clin Infect Dis. 2006 Dec 15;43(12):1565-1577. Epub 2006 Nov 8.<script language="JavaScript1.2"> <!-- var PopUpMenu2_LocalConfig_jsmenu3Config = [ ["ShowCloseIcon","yes"], ["Help","'/entrez/query/static/popup.html','Links_Help','resizable=no,scrollbars= yes,toolbar=no,location=no,directories=no,status=n o,menubar=no,copyhistory=no,alwaysRaised=no,depend =no,width=400,height=500');"], ["TitleText"," Links "] ] var jsmenu3Config = [ ["UseLocalConfig","jsmenu3Config","",""] ] //--> </script> <script language="JavaScript1.2"> <!-- var Menu17109290 = [ ["UseLocalConfig","jsmenu3Config","",""], ["Books","' db=pubmed&list_uids=17109290&dopt=Books'","",""] ] //--> </script> Links
    </dt><dd class="abstract" id="abstract17109290">Beyond Viruses: Clinical Profiles and Etiologies Associated with Encephalitis.
    Viral and Rickettsial Disease Laboratory, California Department of Health Services, Richmond, CA, 94804, USA.
    Background. Encephalitis is a complex syndrome, and its etiology is often not identified. The California Encephalitis Project was initiated in 1998 to identify the causes and further describe the clinical and epidemiologic characteristics of encephalitis.Methods. A standardized report form was used to collect demographic and clinical data. Serum, cerebrospinal fluid, and respiratory specimens were obtained prospectively and were tested for the presence of herpesviruses, arboviruses, enteroviruses, measles, respiratory viruses, Chlamydia species, and Mycoplasma pneumoniae. The association between an identified infection and encephalitis was defined using predetermined, organism-specific criteria for confirmed, probable, or possible causes.Results. From 1998 through 2005, a total of 1570 patients were enrolled. Given the large number of patients, subgroups of patients with similar clinical characteristics and laboratory findings were identified.

    </dd><dd class="abstract" id="abstract17109290">
    </dd><dd class="abstract" id="abstract17109290">Ten clinical profiles were described.A confirmed or probable etiologic agent was identified for 16% of cases of encephalitis:
    </dd><dd class="abstract" id="abstract17109290">
    </dd><dd class="abstract" id="abstract17109290">69% of these agents were viral; 20%, bacterial;

    </dd><dd class="abstract" id="abstract17109290">7%, prion; 3%, parasitic; and 1%, fungal. An additional
    </dd><dd class="abstract" id="abstract17109290">13% of cases had a possible etiology identified.

    </dd><dd class="abstract" id="abstract17109290">Many of the agents classified as possible causes are suspected but have not yet been definitively demonstrated to cause encephalitis;

    </dd><dd class="abstract" id="abstract17109290">these agents include M. pneumoniae (n=96), influenza virus (n=22), adenovirus (n=14), Chlamydia species (n=10), and human metapneumovirus (n=4).

    </dd><dd class="abstract" id="abstract17109290">
    </dd><dd class="abstract" id="abstract17109290">A noninfectious etiology was identified for 8% of cases, and no etiology was found for 63% of cases.
    </dd><dd class="abstract" id="abstract17109290">
    </dd><dd class="abstract" id="abstract17109290">Conclusions. Although the etiology of encephalitis remains unknown in most cases, the recognition of discrete clinical profiles among patients with encephalitis should help focus our efforts toward understanding the etiology, pathogenesis, course, and management of this complex syndrome.
    </dd><dd class="abstract" id="abstract17109290">

    PMID: 17109290 [PubMed - as supplied by publisher]