March 30, 1995
Encephalitis Lethargica
Dear Colleagues,
I recently watched an interesting film, called the Awakenings (1990),
with Robin Williams portraying a Research Neurologist (Dr Sayer), and Robert
De Niro as a comatose patient, by the name Leonard.
The film centred around patients, whom had survived a 1920's encephalitis
epidemic (Encephalitis Lethargica), following treatment with a 'wonder drug'
(levodopa) in the 1970's.
The 'patients' were found to have developed postencephalitic parkinsonism
(a movement disorder marked by symptoms such as tremor, rigidity, immobility,
and severely disturbed eye movements. Their treatment with levodopa brought
about remarkable improvement in their conditions, but most returned to their
former state due to inability to cope with this "awakening".
The film also pointed out the ethics of using comatose patients as guinea
pigs.
I have researched into the condition through various texts, and have found
that Encephalitis is most commonly caused by the herpes simplex virus type 1
(HSV1), though an increasing number of cases are caused by infection with
HIV, which is responsible for AIDS. The literature also reveals that the
current effective treatment for Herpes simplex infection is by intravenous
infusion of the antiviral drug, acyclovir, though for other viral infections,
no effective treatment is known.
This has prompted me to consider :
1. How do these viruses cause inflammation of the brain?
2. Do these viruses affect the same neurones that induce parkinsonium
symptoms?
3. How does levodopa function?
4. Does it function in the same way as for treatment in parkinson?
5. Do Parkinsonium and Encephalitis share some form of biochemical pathway?
6. Would the introduction of foetal tissue bring about a similar type of
response?
7. What about the use of other drugs used for Parkinson treatment, such as
Bromocriptine and Amantadine?
8. Why should these virus only affect, in most cases, very few number of
people?
9. Why should symptoms vary so widely, from slight tremor to coma and death?
I believe that since some form of response results from treatment with
levodopa the neurones that are affected by this virus are within the basal
ganglia. If the way inwhich the virus causes these symptoms is understood,
the mechanism of Parkinsonium may also be understood.
I am interested in some of the current research surrounding this particular
disease and would appreciate any information on research, or views about this
posting to be sent to the email address below :
ywl at ic.ac.uk
Many thanks,
Yat Wah Li
Y.W.Li
Department of Biochemistry
Imperial College
London
