Autoimmune Encephalitis history and symptoms
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Julinka Auta Fernandes
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Autoimmune Encephalitis Microchapters |
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Differentiating Autoimmune Encephalitis from Other Conditions |
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Diagnosis |
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Treatment |
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Case Studies |
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Autoimmune Encephalitis On the Web |
Overview
Autoimmune encephalitis symptoms include new memory difficulties, confusion, behavioral or psychiatric changes, and seizures. Speech disturbance, sleep disruption, unwanted movements, and reduced awareness may also occur. The combination and sequence vary between patients and antibody-associated subtypes.[1]
Symptoms usually evolve over days to weeks, commonly within less than 3 months. Some antibody-associated illnesses develop more slowly. A preceding headache, fever, or flu-like illness may occur, but its absence does not exclude autoimmune encephalitis.[2]
History
History of present illness
Autoimmune encephalitis assessment should include a detailed account from the patient and, whenever possible, a relative, caregiver, or other person familiar with the patient's baseline. Patients may not recognize or remember their own changes.[3]
Document:
- Onset and progression: Date of the first change, order of subsequent symptoms, fluctuations, and rate of deterioration.
- Memory and thinking: Repeated questions, forgotten conversations, disorientation, difficulty following instructions, or impaired everyday decisions.
- Behavior and psychiatric symptoms: New anxiety, irritability, suspiciousness, hallucinations, unusual beliefs, agitation, or behavior markedly different from baseline.
- Seizure descriptions: Staring, brief interruptions of activity, unusual sensations, repetitive movements, jerking, falls, or episodes of lost awareness. Ask witnesses about frequency, duration, and recovery.
- Speech, movement, and sleep: Reduced speech, difficulty finding words, unwanted movements, stiffness, disturbed sleep, or excessive daytime sleepiness.
- Functional impact: Changes in personal care, medication management, work, study, relationships, and the need for supervision.[1][3]
Past medical and medication history
Autoimmune encephalitis history-taking should establish previous neurological and psychiatric diagnoses and whether the current symptoms represent an acquired change. Relevant questions include:
- Prior encephalitis, especially herpes simplex virus encephalitis, and new deterioration after initial improvement.
- Previous seizures, similar neurological episodes, cognitive impairment, or autoimmune disease.
- Known cancer, recent cancer treatment, unexplained weight loss, and other symptoms suggesting an associated neoplasm.
- Recent introduction or withdrawal of medicines, including cancer immune checkpoint inhibitors and other immune-modifying treatments.
- Recent infections and immunosuppression, which also influence the differential diagnosis.
- A complete medication list, nonprescription products, substance use, and drug allergies.[2][3]
Family and social history
Autoimmune encephalitis assessment should document family neurological, psychiatric, and autoimmune history, alongside the patient's usual cognitive and functional abilities. Record alcohol intake and frequency, recreational drug use, smoking, occupation, and relevant travel or exposure history when assessing alternative explanations.[2][3]
History in children and adolescents
Autoimmune encephalitis in children may be recognized through acquired behavioral change, loss of language or previously learned skills, new seizures, or unusual movements. Ask parents and teachers about developmental baseline, school performance, attention, play, sleep, and the timing of regression.[4]
Younger children may be unable to describe memory loss or unusual experiences. Pre-existing developmental or psychiatric difficulties do not prevent a new autoimmune illness, but make careful baseline comparison and consideration of genetic, metabolic, and other causes particularly important.[4]
Common Symptoms
Autoimmune encephalitis commonly affects memory, cognition, behavior, and seizure control. The following are recurring symptom domains; no patient is required to experience every feature:[1]
| Symptom domain | Examples reported by the patient or witnesses |
|---|---|
| Memory and cognitive difficulties | Forgetting recent events, repeatedly asking the same question, losing track of conversations, or struggling with familiar tasks. |
| Confusion or altered awareness | Appearing disoriented, behaving inconsistently, becoming unusually drowsy, or having periods of reduced responsiveness. |
| Behavioral and psychiatric changes | New agitation, fearfulness, irritability, hallucinations, paranoia, disinhibition, or marked personality change. |
| Seizures | Convulsions, staring spells, brief behavioral arrest, repetitive movements, or episodes of impaired awareness; some events are subtle. |
| Speech and language disturbance | Difficulty expressing thoughts, speaking much less, unusually pressured speech, or becoming mute. |
| Sleep disturbance | Difficulty sleeping, a disrupted sleep–wake pattern, or excessive sleepiness. |
The combination of rapidly evolving psychiatric symptoms with seizures, unusual movements, or altered awareness should prompt consideration of encephalitis. These symptoms also have other causes and do not establish an autoimmune diagnosis by themselves.[3]
Less Common Symptoms
Autoimmune encephalitis may also produce the following symptoms. Their frequency depends strongly on subtype and severity; some are prominent in particular antibody-associated illnesses rather than rare within those illnesses.
- Unwanted movements or stiffness: Repetitive lip or tongue movements, abnormal posturing, jerks, tremor, or episodes of marked rigidity.[5]
- Autonomic complaints: Episodes of excessive sweating, palpitations, faintness, or other symptoms accompanying autonomic instability.
- Breathing disturbance or profound unresponsiveness: These can develop in severe disease and may be noticed by caregivers rather than reported by the patient.[5]
- Pain, muscle cramps, or persistent twitching: Particularly relevant when encephalitic symptoms coexist with peripheral nerve hyperexcitability.[6]
- Unsteadiness or other focal neurological complaints: New difficulty walking, incoordination, or focal deficits may accompany selected presentations.[2]
- Persistent diarrhea and major weight loss before neurological symptoms: A clue to a particular uncommon antibody-associated syndrome, rather than a general feature of autoimmune encephalitis.[7]
Selected antibody-associated symptom patterns
Autoimmune encephalitis symptom patterns can suggest an antibody association, but overlap is substantial and clinical features alone do not determine antibody status.
| Association | Historical clues |
|---|---|
| N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis | Behavioral or psychiatric change may be followed by reduced speech, seizures, unwanted movements, altered awareness, autonomic symptoms, or breathing disturbance. The full sequence is not present in every patient.[5] |
| Leucine-rich glioma-inactivated protein 1 (LGI1) antibody encephalitis | Memory difficulty and seizures. Very brief, frequent contractions affecting the face and arm, termed faciobrachial dystonic seizures, may precede cognitive decline.[8] |
| Contactin-associated protein-like 2 (CASPR2) antibody-associated disease | Memory or seizure symptoms may coexist with severe insomnia, neuropathic pain, muscle twitching or cramps, and autonomic complaints. The broader disease spectrum includes peripheral as well as central neurological involvement.[6] |
| Gamma-aminobutyric acid type B receptor (GABABR) antibody encephalitis | Seizures can be particularly prominent or difficult to control, alongside memory and behavioral changes.[1] |
| Dipeptidyl-peptidase-like protein 6 (DPPX) antibody-associated encephalitis | Diarrhea and weight loss may precede cognitive or behavioral symptoms, exaggerated startle, and muscle jerks.[7] |
Symptoms requiring urgent assessment
Autoimmune encephalitis should be considered urgently when new cognitive or behavioral change is accompanied by repeated or prolonged seizures, rapidly declining responsiveness, or breathing difficulty. These presentations require urgent evaluation for infectious, autoimmune, and other serious causes.[3]
References
- ↑ 1.0 1.1 1.2 1.3 Hahn C, Budhram A, Alikhani K; et al. (2024). "Canadian Consensus Guidelines for the Diagnosis and Treatment of Autoimmune Encephalitis in Adults". Canadian Journal of Neurological Sciences. 51 (6): 734–754. doi:10.1017/cjn.2024.16. PMID 38312020 Check
|pmid=value (help). - ↑ 2.0 2.1 2.2 2.3 Abboud H, Probasco JC, Irani S; et al. (2021). "Autoimmune encephalitis: proposed best practice recommendations for diagnosis and acute management". Journal of Neurology, Neurosurgery & Psychiatry. 92 (7): 757–768. doi:10.1136/jnnp-2020-325300. PMID 33649022 Check
|pmid=value (help). - ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Michael BD, Huang Y, McKeever S; et al. (2026). "Management of suspected infectious and autoimmune encephalitis in adults – National Guidelines from the United Kingdom Joint Societies". Journal of Infection: 106873. doi:10.1016/j.jinf.2026.106873. PMID 42863638 Check
|pmid=value (help). - ↑ 4.0 4.1 Cellucci T, Van Mater H, Graus F; et al. (2020). "Clinical approach to the diagnosis of autoimmune encephalitis in the pediatric patient". Neurology: Neuroimmunology & Neuroinflammation. 7 (2): e663. doi:10.1212/NXI.0000000000000663. PMID 31953309.
- ↑ 5.0 5.1 5.2 Graus F, Titulaer MJ, Balu R; et al. (2016). "A clinical approach to diagnosis of autoimmune encephalitis". The Lancet Neurology. 15 (4): 391–404. doi:10.1016/S1474-4422(15)00401-9. PMID 26906964.
- ↑ 6.0 6.1 van Sonderen A, Ariño H, Petit-Pedrol M; et al. (2016). "The clinical spectrum of Caspr2 antibody-associated disease". Neurology. 87 (5): 521–528. doi:10.1212/WNL.0000000000002917. PMID 27371488.
- ↑ 7.0 7.1 Hara M, Ariño H, Petit-Pedrol M; et al. (2017). "DPPX antibody-associated encephalitis: Main syndrome and antibody effects". Neurology. 88 (14): 1340–1348. doi:10.1212/WNL.0000000000003796. PMID 28258082.
- ↑ Thompson J, Bi M, Murchison AG; et al. (2018). "The importance of early immunotherapy in patients with faciobrachial dystonic seizures". Brain. 141 (2): 348–356. doi:10.1093/brain/awx323. PMID 29272336.