by Alina Ellerington, Projects and Information Officer.

Research Summary - Advances in Encephalitis 2019

During Encephalitis Research Month (June), we have launched Research Summary - Advances in Encephalitis 2019 which presents a collection of research papers published during that same year. These papers cover everything from geographical distribution of different types of encephalitis, causes, symptoms, diagnosis and treatment to recovery and rehabilitation. Below, we summarised the main research findings. For complete details and references of these studies please see the full Research Summary.

A study in Australia looked at what caused encephalitis in children and found that most children had a cause for their encephalitis identified: infectious (viral, bacterial) or autoimmune with viral encephalitis being the most frequent. In only a small proportion of children the doctors did not know what caused their encephalitis. This is quite a low rate of unknown cause-encephalitis which shows a progress in diagnosis encephalitis. This is partly explained through the use of current diagnosis guidelines, greater awareness of autoimmune encephalitis and new diagnostic methods.

One of a new diagnostic tools is called next generation sequencing (NGS) of cerebrospinal fluid (CSF) and it has been shown that it can detect more potential pathogens (i.e. viruses) than previous conventional testing. However, difficulties in diagnosing still exist. The variety of symptoms and signs together with the reluctance to perform certain tests (e.g. lumbar puncture), lack of or poor resources, insufficient medical training are considered barriers in diagnosing encephalitis. As a result, research continued to focus on distinguishing encephalitis from other illness with similar presentations or finding new clues to the diagnosis. Emphasis was also on the fact that clinicians should consider encephalitis in patients with atypical clinical presentations (symptoms and tests results) such as for example the case of autoimmune encephalitis in older adults with rapid progressive memory loss, anti-NMDAR encephalitis in women with concomitant mood and psychotic disorders, or herpes simplex encephalitis with atypical test results.

An increase in the number of cases and emergence of new areas for viruses associated with encephalitis, such as tick-borne encephalitis and West Nile virus, was observed in 2019. Tick-borne encephalitis virus was discovered in the UK (South England). This growth has many implications for travel health (vaccination if it exists and recommended and preventive measures). When looking for travel health advice, travellers should be advised not only on the likelihood, but also on the severity of the consequences of encephalitis if acquired.

Anti-NMDAR encephalitis is the most common type of autoimmune encephalitis and has the most research dedicated to it. One of the challenges in its management is prompt recognition of symptoms. As initial symptoms include psychiatric manifestation, it can be difficult to know when these psychiatric symptoms are psychiatric and when they mean neurological illness. Studies looked at finding a specific pattern that can be used to diagnose quickly this condition. A research team at John Radcliffe Hospital, Oxford found that patients with anti-NMDAR encephalitis do not present with manifestations that fit the traditional psychiatric classifications, but exhibit a complex presentation in which various symptoms that belong to different disorders coexist. Agitation, aggression, hallucinations, delusions, mutism, irritability or mood instability and depressed mood—characterise the presentation of patients with anti-NMDAR encephalitis. This complex profile associated with a predominantly young, female demographic can help distinguish patients with anti-NMDAR encephalitis from patients with new onset mental illness and justify the need for lumbar puncture, and consequently treatment with immunotherapy.

Treatments for anti-NMDAR encephalitis such as of mycophenolate mofetil (MMF), azathioprine (AZA), methotrexate (MTX) were also investigated. The researchers found that, although larger studies are needed, these initial studies show that these drugs can be effective and may reduce the risk of relapse. A study that investigated the effects of plasma exchange in the refractory cases of anti-NMDAR (those that do not respond to initial treatment) found that the effects are positive by rapidly improving the symptoms in these patients. Caring for people with autoimmune encephalitis in hospital is very complex. Administering treatment, keeping patients safe, dealing with complications and also more ethical aspects such as the decision to ovariectomy in young women show that nursing care of these patients is challenging but essential in order to maintain the safety of patients and improve outcomes.

In 2019, a few research papers were dedicated to an antibody that, in the past, has been found in patients with other conditions such as demyelinating syndromes. This antibody is called MOG antibody and has recently been associated not only with a demyelinating encephalitis (ADEM), but also encephalitis other than ADEM. It can affect both children and adults and it can be monophasic or relapsing.

Sleep abnormalities are a common feature of autoimmune encephalitis. In a study investigating sleep disturbances (new or worsening), most patients had those disturbances. No association was made between the sleep disturbances and age or gender. However, different antibodies had an increased risk of specific sleep disturbances. In more than a quarter of patients, sleep disturbances of varying intensity persisted after the acute phase. Screening, prompt recognition and treatment of these disturbances are suggested in order to improve patients’ outcomes.

Another important feature of autoimmune encephalitis is seizure. Studies showed not only the beneficial effect of immunotherapy on their management, but also the rare likelihood of developing epilepsy after autoimmune encephalitis. As a consequence, long-term antiepileptic medication may not be justified in all types of autoimmune encephalitis. This finding has major implications on patients’ quality of life.

Despite all these advances, the burden of encephalitis remains high. After acute illness, patients can be left with long-term consequences and the impact on the whole family can be devastating. In a childhood encephalitis study, 27% of children were assessed to have moderate to severe neurological difficulties at discharge. A study on the consequences of Japanese encephalitis captures interviews with patients and their families. The words and phrases the interviewees used are reflective of the impact JE has had on their lives: “strange”, “scary”, “devastating”, “shock”, “it is not anything you imagine”, “this is for life”.

The few studies available on rehabilitation showed that multi-stage, person-centred and interdisciplinary rehabilitation is essential in improving lives after encephalitis. In addition, studies looked at finding prognosis factors to know why some people recover well and other don’t. Having reliable prognosis factors can help doctors and therapists in identifying those patients who need an additional input and monitoring, and in educating families on what to expect after the acute illness.

Once again, the huge amount of studies around the world showed that there is interest in encephalitis research and progress in understanding this illness is made. However, there is still a lot to learn and discover. And this is why Encephalitis Research Month is important to say thank you to all doctors and researchers out there but also to ask for more investment and participation in research.