Misdiagnosed, Dismissed, and Running Out of Time |
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Autoimmune encephalitis often presents with psychiatric or cognitive symptoms, delaying diagnosis.
Many patients first present to psychiatry or other services because symptoms mimic common conditions.
Awareness must be balanced with careful testing to avoid harmful over-diagnosis and mistreatment.
Dr. Tom Pollak, Ph.D., MRCPsych, Reader in Immunopsychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London; Scientific Advisory Panel Member, Encephalitis International.
Felicity Amberson-Jones, MSc, Research Assistant, Institute of Psychiatry, Psychology and Neuroscience, King's College London.
Autoimmune encephalitis doesn’t always announce itself—and when it doesn’t, patients pay the price. Autoimmune encephalitis is an immune-mediated inflammation of the brain. It tends to present in a number of recognisable patterns, but these patterns themselves can be quite varied and, problematically for doctors, these patterns are frequently more commonly seen in branches of medicine other than neurology. That means diagnosis can be tricky, and that in turn means that there can sometimes be a considerable delay between the time that the symptoms first come on and the time that the diagnosis is correctly made. This, of course, can result in delays in receiving the appropriate treatment, and as in many neurological diseases, the quicker that a patient gets the treatment they need, the better their outcomes will be on the other side.In autoimmune encephalitis, the immune system starts reacting to proteins involved in brain function. People can become acutely confused or frightened. They can develop seizures, abnormal movements, sleep disruption, changes in speech, or memory problems. In some cases, psychiatric symptoms dominate early: paranoia, hallucinations, bizarre beliefs, agitation, catatonia, behavioural change. Families often describe an abrupt shift in personality and reality-testing that feels like a sudden change from the person they know. This is where misdiagnosis often begins.
Presentations sometimes enter the health care system through the medical speciality that matches the ‘loudest’ or most prominent symptom at the time. Someone who is hallucinating and distressed may be managed as first-episode psychosis, whereas an older person who is disorientated may be treated as delirium with an expected trigger, like a urinary tract infection. If the disorientation and confusion comes on a little bit slower in an older person, they may be channelled into dementia pathways. Someone with brief collapses or dizziness may be worked up in cardiology, whereas someone with seizures that are unusual in form or do not have an obvious correlate on EEG testing (in which the brain's electrical waves are measured) may be labelled with functional neurological disorder or non-epileptic seizures. Each of these starting points can be reasonable, because in terms of sheer numbers, these are often likely to be the most probable diagnosis. The difficulty is that in some cases, autoimmune encephalitis can be lurking behind them.
Anti-NMDA receptor encephalitis is a clear example of why psychiatry is a common front door. Early symptoms are often psychiatric, particularly in children and young adults, and the demographic overlap with first-episode psychosis can make early presentations genuinely hard to separate at first glance. Many patients are first assessed by psychiatry before more overt neurological features appear. One early study reported that around 77% of patients were initially evaluated by mental health services. This does not mean that every one of these patients received a primary mental health diagnosis like schizophrenia, but it does suggest strongly that people working in psychiatry and mental health services need to be as informed as they possibly can be about how to spot this group of conditions. As illness evolves, features like seizures, marked confusion, abnormal movements, reduced consciousness, or autonomic disturbance may enter the picture, and the overall pattern starts to look less like a standalone psychiatric syndrome.
But even getting the correct diagnosis does not mean abandoning the treatments that were helping manage the presenting symptoms. Many patients with autoimmune encephalitis still need active psychiatric and medical symptom treatment alongside immunotherapy, including careful use of antipsychotics for severe agitation or psychotic symptoms, and prompt treatment of catatonia, anxiety, and sleep disturbance when these are present.
Other autoimmune encephalitis subtypes have their own characteristic routes into this confusing terrain. In older adults, autoimmune encephalitis can resemble a rapidly progressive cognitive and behavioural syndrome that prompts dementia or delirium labels. In LGI1 encephalitis, brief recurrent episodes and falls can be interpreted as fainting spells, transient events, panic, or “funny turns,” especially in later life. In DPPX encephalitis, prominent gastrointestinal symptoms and weight loss can lead to prolonged work-up in gut clinics before neurological features become obvious. The details vary, but the common thread is the same: early symptoms can fit familiar templates, and the autoimmune diagnosis can remain just out of sight of the treating clinicians.
Autoimmune encephalitis often changes shape over days to weeks. People can look better one hour and markedly worse the next, especially early on. Confusion may come and go, behaviour can shift quickly, and often seizures or unusual movements may appear after a period that looked ‘purely psychiatric.’ Sometimes the first clue is simply that the expected course is not happening, or that treatment aimed at the initial diagnosis does not lead to the kind of stabilisation everyone was hoping for, and the overall picture keeps evolving. Improving recognition of autoimmune encephalitis is deeply needed. Many patients still reach the correct diagnosis late, and that delay can matter because immune-based treatment can be highly effective.
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The risk of misdiagnosis
Awareness, though, brings a second challenge that is starting to show up more often in specialist services: some people are being diagnosed with autoimmune encephalitis inappropriately, sometimes on the basis of non-specific symptoms plus a borderline or difficult-to-interpret test result. In those situations, an autoimmune label can send care down an unhelpful path, including exposure to immunotherapies that carry risks, alongside missed opportunities to treat the actual cause of the symptoms. The safest route requires careful clinical judgment supported by the right investigations. Clinicians have developed criteria and “red flag” frameworks to help decide when autoimmune encephalitis is plausible enough to investigate, and how to interpret results in context. These tools are designed to reduce missed cases and also reduce premature diagnoses that rest on thin evidence.
For patients and families, practical help often comes from giving teams the clearest timeline possible: when did the change begin, and how fast did it progress? What changed first? What has appeared since? If symptoms are developing quickly, especially when psychiatric change is accompanied by confusion, seizures, abnormal movements, marked disorientation, or fluctuating consciousness, it is reasonable to ask whether autoimmune encephalitis is on the differential and whether specialist advice is needed. That question tends to land best when it is framed as wanting to make sure the team has considered the full range of possibilities.
Autoimmune encephalitis remains uncommon. Early recognition can make an enormous difference for the people who do have it. Getting this right asks for two things at once: better awareness of the condition’s real-world presentations, and enough rigour to avoid turning uncertainty into an autoimmune diagnosis by default.