Autoimmune Encephalitis pediatric considerations
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Julinka Auta Fernandes
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Overview
Autoimmune encephalitis in children requires assessment of developmental change and age-specific presentations. N-methyl-D-aspartate receptor (NMDAR) antibody encephalitis is the most common recognized neuronal antibody-mediated subtype in childhood. Pediatric diagnostic recommendations complement adult criteria; they are provisional classification criteria rather than a single definitive test.[1]
Clinical Presentation
- Look for an acute or subacute change from the child's baseline, including developmental regression, language loss, cognitive difficulties, seizures, movement abnormalities, or altered behavior and consciousness.
- Obtain observations from caregivers and teachers; young children may be unable to describe memory or psychiatric symptoms.
- New psychiatric symptoms accompanied by neurological abnormalities warrant investigation for medical causes.[1]
Severe NMDAR antibody encephalitis may involve autonomic instability, reduced consciousness, and impaired breathing. These manifestations require urgent hospital assessment and sometimes pediatric intensive care.[2]
Diagnostic Evaluation
Core Investigations
- Examine blood and cerebrospinal fluid (CSF) for relevant neuronal antibodies and investigate infection and other mimics.
- Obtain brain magnetic resonance imaging (MRI) and electroencephalography (EEG). EEG abnormalities support brain dysfunction but do not independently demonstrate inflammation.
- Probable antibody-negative pediatric disease requires supportive evidence of neuroinflammation and exclusion of alternatives; symptoms alone are insufficient.[1]
For suspected NMDAR antibody encephalitis, CSF testing is essential because serum-only testing may produce misleading results. A negative antibody panel does not exclude every autoimmune syndrome, and an isolated positive result must fit the phenotype.[3]
A multicenter pediatric NMDAR antibody encephalitis study found that MRI was frequently normal. Abnormalities were not confined to the medial temporal lobes; a normal scan should therefore not end an otherwise appropriate investigation.[4]
Differential Diagnosis
Important alternatives include infectious encephalitis, genetic or metabolic encephalopathies, epilepsy-related disorders, toxic exposures, primary psychiatric illness, and inflammatory demyelination such as acute disseminated encephalomyelitis. Investigation should reflect the presentation rather than relying on a positive antibody result or apparent steroid response.[1][3]
New neurological deterioration after herpes simplex encephalitis may reflect infection relapse or postinfectious autoimmune encephalitis; both require evaluation.[3]
Treatment Considerations
Early Management
When clinical evidence strongly supports autoimmune encephalitis, treatment may begin before antibody results return after reasonable exclusion of infection and other alternatives. Empirical antiviral treatment may be needed while infectious investigations proceed. Neurology, infectious diseases, intensive care, and rehabilitation teams should coordinate care.[5]
Pediatric NMDAR Antibody Encephalitis
The international pediatric consensus recommends:
- Corticosteroids, preferably intravenous pulse treatment, with intravenous immunoglobulin (IVIG) or plasma exchange added in severe disease.
- Consideration of second-line treatment, preferably rituximab, when improvement is inadequate approximately two weeks after initiation of two or more first-line therapies.
- Individualized treatment duration. Maintenance immunosuppression beyond six months is generally unnecessary, but may be appropriate with severe, prolonged, or relapsing disease.[2]
These recommendations are specific to NMDAR antibody encephalitis. Other antibody-associated or antibody-negative syndromes require specialist decisions rather than automatic application of the same escalation schedule.
Supportive Care
Manage seizures, agitation, sleep disturbance, nutrition, mobility, and autonomic complications. Distinguish abnormal movements from seizures when possible using video-EEG. Monitor medication adverse effects and infection risk during immunotherapy.[5]
Screening for an Associated Neoplasm
Early tumor screening is recommended for all children with NMDAR antibody encephalitis. Tumors are uncommon in boys and prepubertal children but remain possible. Use age-appropriate abdominal and pelvic imaging and selected chest imaging. Repeat assessment is important with poor improvement or relapse, particularly in postpubertal females at risk of ovarian teratoma.[2]
For details, see screening for an associated neoplasm.
Recovery, Schooling, and Follow-Up
Pediatric NMDAR antibody encephalitis may leave persistent difficulties with attention, memory, behavior, and fatigue despite apparently good physical recovery. A pediatric follow-up study documented substantial educational consequences, supporting early neuropsychological assessment and attention to school functioning.[6]
- Assess cognition, language, mood, sleep, fatigue, and daily functioning rather than motor recovery alone.
- Coordinate rehabilitation and a gradual return to school, with individualized educational adjustments.
- Include caregivers in planning and review difficulties that become apparent as academic demands increase.[6]
New deterioration requires reassessment for relapse, infection, seizures, medication effects, and other causes. Relapsing NMDAR antibody encephalitis may require more prolonged immunotherapy.[2][5]
References
- ↑ 1.0 1.1 1.2 1.3 Cellucci T, Van Mater H, Graus F, et al. Clinical approach to the diagnosis of autoimmune encephalitis in the pediatric patient. Neurol Neuroimmunol Neuroinflamm. 2020;7(2):e663. doi:10.1212/NXI.0000000000000663. PMID:31953309.
- ↑ 2.0 2.1 2.2 2.3 Nosadini M, Thomas T, Eyre M, et al. International Consensus Recommendations for the Treatment of Pediatric NMDAR Antibody Encephalitis. Neurol Neuroimmunol Neuroinflamm. 2021;8(5):e1052. doi:10.1212/NXI.0000000000001052. PMID:34301820.
- ↑ 3.0 3.1 3.2 Graus F, Titulaer MJ, Balu R, et al. A clinical approach to diagnosis of autoimmune encephalitis. Lancet Neurol. 2016;15(4):391–404. doi:10.1016/S1474-4422(15)00401-9. PMID:26906964.
- ↑ Gombolay G, Brenton JN, Yang JH, et al. MRI Features and Their Association With Outcomes in Children With Anti-NMDA Receptor Encephalitis. Neurol Neuroimmunol Neuroinflamm. 2023;10(4):e200130. doi:10.1212/NXI.0000000000200130. PMID:37236807.
- ↑ 5.0 5.1 5.2 Abboud H, Probasco JC, Irani S, et al. Autoimmune encephalitis: proposed best practice recommendations for diagnosis and acute management. J Neurol Neurosurg Psychiatry. 2021;92(7):757–768. doi:10.1136/jnnp-2020-325300. PMID:33649022.
- ↑ 6.0 6.1 de Bruijn MAAM, Aarsen FK, van Oosterhout MP, et al. Long-term neuropsychological outcome following pediatric anti-NMDAR encephalitis. Neurology. 2018;90(22):e1997–e2005. doi:10.1212/WNL.0000000000005605. PMID:29703768.