Anti-NMDA receptor encephalitis in a toddler: A diagnostic challenge

Anti-N-Methyl-D-Aspartate Receptor Encephalitis: Neuropsychiatric and Multidisciplinary Approach to a Patient Not Responding to First-Line Treatment

The understanding of anti-NMDA (N-methyl-D-aspartate) receptor encephalitis, recognized by Dalmau and colleagues in 2007, has come a long way in helping clinicians to recognize the significance of rapidly progressive psychiatric symptoms in patients who are actually suffering from autoimmune disease. This subtype of autoimmune encephalitis manifests from antibodies that target the NR1 and/or NR2 subunits of NMDA receptors in serum or cerebrospinal fluid. Since gaining notoriety among neurologists, it has shown an etiologic predilection for children, adolescents, and young adult females, often associated with ovarian teratomas. Conversely, it affects young males as well, though it is rarer to find co-occurring tumors. It is a multistage disorder, initially presenting with psychiatric symptoms that progress in varying fashion, including headache, fever, nuchal rigidity, emesis, seizure, autonomic instability, auditory and visual hallucinations, delusional ideation, agitation, altered sensorium, and motor disturbances (i.e. dyskinesia, catatonia, etc.). Early diagnosis is critical due to the relatively high (25%) mortality rate. In this case, we present the case of a 30-year-old male who presented to our institution’s Comprehensive Psychiatric Emergency Program (CPEP) exhibiting bizarre behavior and visual hallucinations, and was later confirmed to have anti-NMDA receptor encephalitis. The case report highlights the risk factors, disease course, and treatment modalities of anti-NMDA receptor encephalitis with special emphasis on the subsect of patients who may not respond to first-line therapies.

Autoimmune Encephalitis and Autism Spectrum Disorder

The concept of "acquired autism" refers to the hypothesis that amongst the massive heterogeneity that encompasses autism spectrum disorder (ASD) there may be several phenotypes that are neither syndromic nor innate. Strong and consistent evidence has linked exposure to various pharmacological and infective agents with an elevated risk of a diagnosis of ASD including maternal valproate use, rubella and herpes encephalitis. Autoimmune encephalitis (AE) describes a group of conditions characterised by the body's immune system mounting an attack on healthy brain cells causing brain inflammation. The resultant cognitive, psychiatric and neurological symptoms that follow AE have also included ASD or autism-like traits and states. We review the current literature on AE and ASD. Drawing also on associated literature on autoimmune psychosis (AP) and preliminary evidence of a psychosis-linked subtype of ASD, we conclude that AE may either act as a potentially causative agent for ASD, and/or produce symptoms that could easily be mistaken for or misdiagnosed as autism. Further studies are required to discern the connection between AE and autism. Where autism is accompanied by regression and atypical onset patterns, it may be prudent to investigate whether a differential diagnosis of AE would be more appropriate.

Clinical Features and Outcomes of Anti-N-Methyl-d-Aspartate Receptor Encephalitis in Infants and Toddlers

OBJECTIVE

We describe the clinical features and outcomes of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis in infants and toddlers.

METHODS

This was a single-center retrospective study. Infants and toddlers who met the diagnostic criteria for anti-NMDAR encephalitis were recruited for the study. Data on clinical features, treatment, and long-term outcomes were collected retrospectively.

RESULTS

A total of 41 patients (age range: six to 34 months; median age: 23 months; female: 19) were enrolled in this study. Nineteen (46%) patients exhibited classical anti-NMDAR encephalitis, whereas 22 (54%) patients exhibited anti-NMDAR encephalitis after viral encephalitis. There was a high presentation of movement disorders (100%), developmental regression (90%), abnormal behaviors (90%). All patients were administered first-line therapy, with only 17% of them being administered second-line immunotherapy. Two patients succumbed to the disease, whereas none of them relapsed. At the long-term follow-up (more than one year), 20 of 35 (57%) exhibited satisfactory outcomes (modified Rankin Scale ≤2). Compared with patients with classical anti-NMDAR encephalitis (n = 18), patients after viral encephalitis (n = 17) were more likely to have worse clinical outcomes. They exhibited a higher modified Rankin Scale/Pediatric Cerebral Performance Category score and more frequent seizures. A predictor of poor outcome was presentation after viral encephalitis (odds ratio 35.7, 95% confidence interval 4.64 to 275.03, P = 0.001).

CONCLUSION

Anti-NMDAR encephalitis in infants and toddlers clinically presents with movement disorders, developmental regression, and abnormal behaviors. Interestingly, this group had a higher proportion of patients after viral encephalitis, which is regarded as the only risk factor for poor outcomes.

The challenge of diagnosing and successfully treating anti-NMDA receptor encephalitis in a toddler

Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is an immune-mediated syndrome that is still under-recognised, with grave consequences if not treated early. A multidisciplinary team approach is required in the process of diagnosis and management of this potentially treatable and reversible disorder. We report on a 26-month-old Sudanese girl who presented with focal seizures associated with fever (temperature = 38.9°C) and history of trivial head trauma a day before. Viral encephalitis was suspected, and she was started on acyclovir and ceftriaxone. Cranial computed tomography revealed small high density in the right frontal lobe, and magnetic resonance imaging showed the features of cortical haemorrhagic lesion at the right frontoparietal lobe. Polymerase chain reaction for herpes simplex virus 1 and 2 revealed negative results. Her condition worsened over the course of 1 week, with recurrent seizures, insomnia, violent chorea and orofacial dyskinesia. Electroencephalography showed diffuse slow activity and the presence of 'extreme delta brush' pattern, a specific abnormality seen in anti-NMDA receptor (NMDAR) encephalitis. Cerebrospinal fluid was positive for anti-NMDAR antibodies (titre = 1:100). She was treated with intravenous (IV) corticosteroids, IV immune globulin, plasma exchange and rituximab. Her condition improved gradually, with full recovery when last seen 19 months after the onset of the disease.

Anti-N-Methyl-D-aspartate receptor encephalitis masquerading as fever of unknown origin

Fever of unknown origin (FUO) is a diagnostic challenge. Anti-N-methyl-D-aspartate receptor encephalitis should be considered in children with FUO and new-onset neurological symptoms without significant encephalopathy.

Anti-NMDA receptor encephalitis: a case study and illness overview

Anti-N-methyl D-aspartate (NMDA) receptor (anti-NMDAR) encephalitis is among one of the most common autoimmune encephalitides. However, variations in clinical presentation and nonsequential multiphasic course often lead to delays in diagnosis. The mild encephalitis (ME) hypothesis suggests a pathogenetic mechanism of low-level neuroinflammation sharing symptom overlap between anti-NMDAR encephalitis and other psychiatric disorders including schizophrenia. Clinical symptoms of anti-NMDAR encephalitis may mimic schizophrenia and psychotic spectrum disorders or substance-induced psychosis. Although initially described in association with ovarian teratomas in women, anti-NMDAR encephalitis has been reported in individuals without paraneoplastic association, as well as in males. It can affect all age groups but is usually lower in prevalence in individuals greater than 50 years old, and it affects females more than males. Clinical evaluation is supported by laboratory workup, which includes cerebrospinal fluid (CSF) assays. The latter often reveals lymphocytic pleocytosis or oligoclonal bands with normal to elevated CSF protein. CSF testing for anti-NMDAR antibodies facilitates diagnostic confirmation. Serum anti-NMDAR antibody assays are not as sensitive as CSF assays. Management includes symptomatic treatment and immunotherapy.