Autoimmune Encephalitis — Brain Inflammation Evaluation

What is autoimmune encephalitis?

Autoimmune encephalitis (also called autoimmune encephalopathy) occurs when the immune system attacks brain tissue or neuronal proteins. Recognized antibody syndromes include anti-NMDA receptor encephalitis, LGI1, CASPR2, GABA-B receptor, AMPA receptor, and several others. Not every case of autoimmune encephalitis has a detectable antibody, however — some patients meet clinical criteria for seronegative autoimmune encephalitis when the picture, imaging, EEG, and CSF findings support it.

Autoimmune encephalitis affects both children and adults. The clinical course can be subacute or fulminant, and early diagnosis matters because timely immunotherapy can change outcomes in selected patients.

What does it look like?

Reported features include:

Memory loss or new cognitive impairment
Confusion or altered mental status
Seizures — sometimes the first manifestation
Psychiatric symptoms: psychosis, hallucinations, agitation, severe anxiety, catatonia
Abnormal movements: chorea, dyskinesias, dystonia, orofacial movements
Autonomic instability: blood pressure swings, heart-rate changes, temperature dysregulation
Reduced level of consciousness
Sleep disturbance — insomnia, severe hypersomnia, or disordered sleep architecture

Why it gets missed

Early in the course, symptoms can look primarily psychiatric — new psychosis or behavioral change in a previously well person. Without a high index of suspicion, the immune contribution may be overlooked. Diagnosis often requires neurologic evaluation, MRI of the brain, EEG, autoantibody panels (serum and CSF), and CSF analysis. Working through this requires coordination across neurology and immunology, with imaging and lab support.

How Dr. McNeil approaches evaluation

Evaluation is individualized but typically includes:

Detailed review of the symptom timeline and any precipitating events (infection, surgery, vaccination, malignancy)
Review of prior neurology records, MRI, EEG, and CSF results when available
Serum and CSF autoantibody panels when clinically indicated
Standard immune workup including immunoglobulins and lymphocyte subsets where appropriate
Infection exclusion and medication review
Coordination with neurology, neuropsychiatry, hospital teams, and other specialists

Some patients have already been seen by neurology before referral; in those cases, the role of clinical immunology may be supportive — reviewing the immune workup, helping coordinate immunotherapy, and advocating for medically appropriate treatment. In other cases, the evaluation starts at Optimed Immunology when the clinical picture has not yet been recognized.

Treatment approach

Treatment of autoimmune encephalitis is individualized and depends on the antibody (if identified), severity, and response to initial therapy. Possible options — chosen in coordination with neurology and the rest of the care team — may include:

First-line immunotherapy: high-dose corticosteroids, IVIG, plasmapheresis
Second-line immunotherapy in selected cases: rituximab, cyclophosphamide
Maintenance therapy in selected cases: mycophenolate or other specialist-directed therapies
Evaluation for an underlying tumor (some forms of autoimmune encephalitis are paraneoplastic) when indicated
Symptomatic management of seizures, movement disorders, and psychiatric symptoms through the appropriate specialists

Treatment is not routine and is not the same for every patient. Decisions are made together with the neurology team based on the specific clinical picture.

Insurance and prior authorization

Dr. McNeil does not accept blanket insurance denials when the medical record supports treatment. For qualified patients, the team pursues the available authorization pathways — including written appeals, peer-to-peer discussions with insurance medical directors, and formal prior authorization review. Some carriers make this process harder than others. The practice continues to advocate for medically appropriate treatment regardless of insurance type.

To be clear: evaluation does not guarantee a diagnosis, and a diagnosis does not guarantee insurance approval for any specific therapy. Treatment decisions are individualized based on clinical findings and supported by objective documentation. Where treatment is appropriate, the team works hard on the patient's behalf.

Treatment pathway at Optimed Immunology

Every patient’s situation is different, but the decision logic for autoimmune encephalitis generally follows these steps. This is not a script — it is a structure that gets adapted to each patient’s history, findings, and goals.

Confirm the picture is consistent	Clinical history, MRI brain, EEG, CSF analysis, serum and CSF autoimmune encephalitis antibody panels when clinically indicated. Diagnosis often relies on a combination of clinical criteria, supportive testing, and exclusion of alternatives. A negative antibody panel does not exclude the diagnosis.
Rule out look-alikes	Infectious encephalitis, metabolic encephalopathy, drug effects, primary psychiatric disease, primary neurologic disease, and paraneoplastic syndromes (which require evaluation for an underlying tumor).
First-line / supportive	Identification and treatment of any underlying trigger; supportive care for seizures, psychiatric symptoms, and autonomic instability through the appropriate specialists.
Advanced treatment options	First-line immunotherapy — corticosteroids, IVIG, plasmapheresis — in selected patients meeting criteria; second-line options (rituximab, cyclophosphamide) in refractory cases; maintenance therapy (mycophenolate, others) in selected patients. All in coordination with neurology.
How Dr. McNeil chooses	Treatment is anchored in the neurology team’s diagnosis and management plan. Clinical immunology contributes to the immune workup, immunotherapy decisions when relevant, and advocacy for medically appropriate treatment.
Monitoring & follow-up	Clinical response, neurology follow-up, MRI and CSF as indicated, and ongoing coordination across treating specialists.
Insurance & prior authorization	IVIG, rituximab, and other immunotherapies in this space typically require extensive medical necessity documentation and may require peer-to-peer discussion. Handled in-house, in coordination with neurology.

Medically reviewed

Donald L. McNeil, MD · Board Certified in Allergy & Immunology and Internal Medicine

Last reviewed: November 2025 · Sources: NIMH · NIH/NINDS · CDC · published consensus criteria · relevant clinical guidelines

This page is provided for educational purposes and does not substitute for clinical judgment or direct medical advice. Treatment decisions are individualized based on your full history, examination, and laboratory findings. If you have an emergency, call 911.

Autoimmune Encephalitis.