National surveillance programme for EL
With the support of the Sophie Cameron Trust, a national surveillance programme has been set up to study the clinical and immunological aspects of encephalitis lethargica (EL).
Encephalitis lethargica (EL) affected a large number of people in a pandemic in the early 1900s. Whilst it is now a rare disorder, it still occurs sporadically; however, its presentation, disease course, treatment response, frequency of occurrence and underlying causes are all relatively unknown. Typically, EL presents as an acute illness in young adults with initial neuropsychiatric features, sleep disturbance and movement disorders. Recent cases have also included children, sometimes with a more benign prognosis than in adults. Histological and biochemical data suggest that autoimmune mechanism play an important role in this disorder and recently specific antibody titres have been detected in affected sporadic cases.
The purpose of the study is to gain near-complete surveillance of the disease across the UK. At present it is anticipated that the surveillance programme will run for 10 years. The information obtained from this study may help us to better diagnose and treat future patients with EL. Long term follow up will assist in promoting better information as well as possible treatment options for the patients.
How the programme works
Initially, the surveillance programme will be notified of EL cases through the British Neurological Surveillance Unit (BNSU) and the British Paediatric Neurology Surveillance Unit (BPNSU). The BNSU and BPNSU circulate a monthly electronic questionnaire to all neurologists and paediatric neurologists in the UK on the occurrence of a number of rare neurological disorders – these will now include EL. If a neurologist records a potential case of EL, the coordinator of the surveillance scheme will be contacted by BNSU or BPNSU.
Inclusion in the study is based on a diagnosis of confirmed (or suspected) EL. Suspected EL cases include individuals with an encephalitic illness not explained by another pathology with symptoms and signs of lethargy, neuropsychiatric features (paranoia, emotional lability, mutism, OCD, catatonia), sleep disturbance (e.g. hypersomnolence, insomnia, sleep inversion), or movement disorder (e.g. parkinsonism, dyskinesia, tics, chorea, tremor, oculogyric crisis). Patients with a positive diagnosis for viral encephalitis or another confirmed neurological illness secondary to hypoxic, ischaemic, vascular, toxic or metabolic causes are excluded.
The scheme coordinator will initially contact the consultant
who identified the patient, with a cover letter to the
clinician, a letter to be forwarded to the patient, and a
reply form for the patient (or their representative). There
will also be a letter
from the Sophie Cameron Trust, offering support. Those
patients who agree to be contacted will be approached to
discuss the study and so that informed consent may be
obtained. The local neurologist or paediatrician will also
provide clinical advice. Consent may also be obtained
through a patientís legal representative, guardian or next
2. Data and sample collection and analysis
Once consent has been obtained, the neurologist will be asked to send a copy of patients’ case notes. These will be reviewed by an adult neurologist, who will be Dr. Anette Schrag (Royal Free Hospital, London) or Prof. Gavin Giovanonni (Bart’s and The London, Queen Mary's School of Medicine and Dentistry), or a paediatric neurologist, Dr. Cheryl Hemingway (Great Ormond Street Hospital, London), depending on the age of the patient. The information obtained from patients’ notes will be entered on a form for database entry.
Data will be stored in a password-protected, encrypted database by the research coordinator, David Holden (Bart’s and The London, Queen Mary's School of Medicine and Dentistry). Patient information will be pseudo-anonymised, with patient codes held in a different location. Data will be analysed to provide epidemiological information (e.g., geographical distribution of patients, age range, and demographic characteristics), and to offer insight into the causes of the disease. The results of the study will be made available to others in the form of publications.
Existing blood and CSF samples will also be requested form consenting patients, to evaluate various biochemical parameters. No additional samples will be sought from patients. Serum may be used for anti-basal ganglia antibody (ABGA) analysis and ASO titre analysis (for diagnosis of streptococcal-associated disorders). Samples will be stored for future use as new tests become available.
7th November 2007