[Autoantibody-associated schizophreniform psychoses: clinical symptomatology]

Autoantibody-associated psychiatric syndromes: a systematic literature review resulting in 145 cases

BACKGROUND

Autoimmune encephalitis (AE) is an important consideration during the diagnostic work-up of secondary mental disorders. Indeed, isolated psychiatric syndromes have been described in case reports of patients with underlying AE. Therefore, the authors performed a systematic literature review of published cases with AE that have predominant psychiatric/neurocognitive manifestations. The aim of this paper is to present the clinical characteristics of these patients.

METHODS

The authors conducted a systematic Medline search via Ovid, looking for case reports/series of AEs with antineuronal autoantibodies (Abs) against cell surface/intracellular antigens combined with predominant psychiatric/neurocognitive syndromes. The same was done for patients with Hashimoto encephalopathy/SREAT. Only patients with signs of immunological brain involvement or tumors in their diagnostic investigations or improvement under immunomodulatory drugs were included.

RESULTS

We identified 145 patients with AE mimicking predominant psychiatric/neurocognitive syndromes. Of these cases, 64% were female, and the mean age among all patients was 43.9 (±22.1) years. Most of the patients had Abs against neuronal cell surface antigens (55%), most frequently against the NMDA-receptor (N = 46). Amnestic/dementia-like (39%) and schizophreniform (34%) syndromes were the most frequently reported. Cerebrospinal fluid changes were found in 78%, electroencephalography abnormalities in 61%, and magnetic resonance imaging pathologies in 51% of the patients. Immunomodulatory treatment was performed in 87% of the cases, and 94% of the patients responded to treatment.

CONCLUSIONS

Our findings indicate that AEs can mimic predominant psychiatric and neurocognitive disorders, such as schizophreniform psychoses or neurodegenerative dementia, and that affected patients can be treated successfully with immunomodulatory drugs.

Clinical manifestations and immunomodulatory treatment experiences in psychiatric patients with suspected autoimmune encephalitis: a case series of 91 patients from Germany

Autoimmune encephalitis (AE) can rarely manifest as a predominantly psychiatric syndrome without overt neurological symptoms. This study's aim was to characterize psychiatric patients with AE; therefore, anonymized data on patients with suspected AE with predominantly or isolated psychiatric syndromes were retrospectively collected. Patients with readily detectable neurological symptoms suggestive of AE (e.g., epileptic seizures) were excluded. Patients were classified as "probable psychiatric AE (pAE)," if well-characterized neuronal IgG autoantibodies were detected or "possible pAE" (e.g., with detection of nonclassical neuronal autoantibodies or compatible cerebrospinal fluid (CSF) changes). Of the 91 patients included, 21 (23%) fulfilled our criteria for probable (autoantibody-defined) pAE and 70 (77%) those for possible pAE. Among patients with probable pAE, 90% had anti-NMDA receptor (NMDA-R) autoantibodies. Overall, most patients suffered from paranoid-hallucinatory syndromes (53%). Patients with probable pAE suffered more often from disorientation (p < 0.001) and impaired memory (p = 0.001) than patients with possible pAE. Immunotherapies were performed in 69% of all cases, mostly with high-dose corticosteroids. Altogether, 93% of the patients with probable pAE and 80% of patients with possible pAE reportedly benefited from immunotherapies (p = 0.251). In summary, this explorative, cross-sectional evaluation confirms that autoantibody-associated AE syndromes can predominantly manifest as psychiatric syndromes, especially in anti-NMDA-R encephalitis. However, in three out of four patients, diagnosis of possible pAE was based on nonspecific findings (e.g., slight CSF pleocytosis), and well-characterized neuronal autoantibodies were absent. As such, the spectrum of psychiatric syndromes potentially responding to immunotherapies seems not to be limited to currently known autoantibody-associated AE. Further trials are needed.

[Hashimoto's encephalopathy-An underdiagnosed disease in psychiatry?]

In recent years, research has increasingly focused on inflammatory processes as a trigger for psychiatric illnesses. Contrary to previous suggestions, clinical pictures with psychiatric features only also can occur, leading to erroneous diagnoses and treatments. We describe the case of a patient who was initially diagnosed paranoid schizophrenia on the basis of the clinical presentation. Antipsychotic treatment was frequently discontinued by the patient also due to inadequate response. After intensifying the diagnostic procedures autoimmune thyroiditis oft he Hashimoto type was detected in the patient. Excluding the other causes, Hashimoto's encephalopathy was considered as a differential diagnosis. The patient agreed to a therapeutic attempt with cortison leading to complete remission of psychotic symptoms thus confirming the diagnosis of steroid-responsive encephalopathy associated with autoimmune thyroiditis.

Anti-NMDA receptor encephalitis and overlapping demyelinating disorder in a 20-year old female with borderline personality disorder: proposal of a diagnostic and therapeutic algorithm for autoimmune encephalitis in psychiatric patients "case report"

BACKGROUND

Anti-NMDA receptor encephalitis (NMDAR-E) is an autoimmune encephalitis (AE) mainly affecting young females. It typically presents with isolated psychiatric symptoms (e.g. depressed mood) at first and neurological abnormalities (e.g. seizures, movement disorders) only develop later. Thus, there is a high risk of overlooking NMDAR-E in patients with preexisting psychiatric illness due to symptom overlap in the prodromal period of the disease when treatment is most effective. Although rare, concomitant or sequential development of a demyelinating disorder is increasingly recognized as an associated disease entity (overlap syndrome), with immediate diagnostic and therapeutic implications.

CASE PRESENTATION

We report a patient with a borderline personality disorder (BPD), which developed NMDAR-E and an overlapping demyelinating disorder with anti-Myelin oligodendrocyte glycoprotein (MOG) -IgG positivity. The initial clinical presentation with predominantly affective symptoms (e.g. mood lability, anxiety, depressed mood) lead us to suspect an exacerbation of the BPD at first. However, acute changes in premorbid behavior, newly developed psychotic symptoms and memory deficits lead us to the correct diagnosis of an AE, which was further complicated by the development of a demyelinating disorder. As a result of impaired illness awareness and psychosis, diagnostic and treatment was difficult to carry out. The symptoms completely remitted after treatment with methylprednisolone 1 g daily for 5 days and 5 cycles of plasma exchange.

CONCLUSIONS

Continuous awareness for neuropsychiatric clinical warning signs in patients with a pre-diagnosed psychiatric disorder is important for a timely diagnosis. Therefore, we believe that the diagnostic and therapeutic algorithm provided here, for the first time specifically addressing patients with preexisting psychiatric illness and integrating overlap syndromes, can be a useful tool. Moreover, in order to timely perform diagnostics and treatment, judicial approval should be obtained rapidly.

Cerebrospinal fluid findings in patients with psychotic symptoms-a retrospective analysis

In current international classification systems (ICD-10, DSM5), the diagnostic criteria for psychotic disorders (e.g. schizophrenia and schizoaffective disorder) are based on symptomatic descriptions since no unambiguous biomarkers are known to date. However, when underlying causes of psychotic symptoms, like inflammation, ischemia, or tumor affecting the neural tissue can be identified, a different classification is used ("psychotic disorder with delusions due to known physiological condition" (ICD-10: F06.2) or psychosis caused by medical factors (DSM5)). While CSF analysis still is considered optional in current diagnostic guidelines for psychotic disorders, CSF biomarkers could help to identify known physiological conditions. In this retrospective, partly descriptive analysis of 144 patients with psychotic symptoms and available CSF data, we analyzed CSF examinations' significance to differentiate patients with specific etiological factors (F06.2) from patients with schizophrenia, schizotypal, delusional, and other non-mood psychotic disorders (F2). In 40.3% of all patients, at least one CSF parameter was out of the reference range. Abnormal CSF-findings were found significantly more often in patients diagnosed with F06.2 (88.2%) as compared to patients diagnosed with F2 (23.8%, p < 0.00001). A total of 17 cases were identified as probably caused by specific etiological factors (F06.2), of which ten cases fulfilled the criteria for a probable autoimmune psychosis linked to the following autoantibodies: amphiphysin, CASPR2, CV2, LGl1, NMDA, zic4, and titin. Two cases presented with anti-thyroid tissue autoantibodies. In four cases, further probable causal factors were identified: COVID-19, a frontal intracranial tumor, multiple sclerosis (n = 2), and neurosyphilis. Twenty-one cases remained with "no reliable diagnostic classification". Age at onset of psychotic symptoms differed between patients diagnosed with F2 and F06.2 (p = 0.014), with the latter group being older (median: 44 vs. 28 years). Various CSF parameters were analyzed in an exploratory analysis, identifying pleocytosis and oligoclonal bands (OCBs) as discriminators (F06.2 vs. F2) with a high specificity of > 96% each. No group differences were found for gender, characteristics of psychotic symptoms, substance dependency, or family history. This study emphasizes the great importance of a detailed diagnostic workup in diagnosing psychotic disorders, including CSF analysis, to detect possible underlying pathologies and improve treatment decisions.

Diagnosing Organic Causes of Schizophrenia Spectrum Disorders: Findings from a One-Year Cohort of the Freiburg Diagnostic Protocol in Psychosis (FDPP)

Introduction: Secondary schizophrenia spectrum disorders (SSDs) have clearly identifiable causes. The Department for Psychiatry and Psychotherapy at the University Hospital Freiburg has continued to expand its screening practices to clarify the organic causes of SSDs. This retrospective analysis was carried out to analyze whether a comprehensive organic diagnostic procedure could be informative in patients with SSDs. Methods and Participants: The “Freiburg Diagnostic Protocol in Psychosis” (FDPP) included basic laboratory analyses (e.g., thyroid hormones), metabolic markers, pathogens, vitamin status, different serological autoantibodies, rheumatic/immunological markers (e.g., complement factors), cerebrospinal fluid (CSF) basic and antineuronal antibody analyses, as well as cranial magnetic resonance imaging (cMRI) and electroencephalography (EEG). The findings of 76 consecutive patients with SSDs (55 with paranoid–hallucinatory; 14 with schizoaffective; 4 with hebephrenic; and 1 each with catatonic, acute polymorphic psychotic, and substance-induced psychotic syndromes) were analyzed. Results: Overall, vitamin and trace element deficiency was identified in 92%. Complement factor analyses detected reduced C3 levels in 11%. Immunological laboratory alterations were detected in 76%. CSF analysis revealed general alterations in 54% of the patients, mostly with signs of blood–brain barrier dysfunction. cMRI analyses showed chronic inflammatory lesions in 4%. Combination of EEG, cMRI, and CSF revealed alterations in 76% of the patients. In three patients, autoimmune psychosis was suspected (4%). Discussion: On the basis of these findings, we conclude that a comprehensive diagnostic procedure according to the FDPP in patients with SSD is worthwhile, considering the detection of secondary, organic forms of SSDs, as well as alterations in “modulating factors” of the disease course, such as vitamin deficiency. Larger studies using comprehensive diagnostic protocols are warranted to further validate this approach.

Probable Autoimmune Depression in a Patient With Multiple Sclerosis and Antineuronal Antibodies

BACKGROUND

In a subgroup of patients with mood disorders, clear-cut organic disorders are responsible for depressive symptoms (e.g., autoimmune diseases such as multiple sclerosis or systemic lupus erythematosus). In these cases, an organic affective disorder can be diagnosed.

CASE PRESENTATION

The authors present the case of a 59-year-old male patient who developed a severe depressive episode over approximately 6 months and was, therefore, admitted to the hospital. In retrospect, he reported that, at age 39, he suffered from self-limiting sensory disturbances and muscle weakness in both legs. The current magnetic resonance imaging of his brain showed several conspicuous FLAIR-hyperintense supratentorial white matter lesions compatible with chronic inflammatory brain disease. Imaging of the spinal axis revealed no clear spinal lesions. Cerebrospinal fluid (CSF) analyses showed CSF-specific oligoclonal bands. Therefore, multiple sclerosis was diagnosed. Further CSF analyses, using tissue-based assays with indirect immunofluorescence on unfixed murine brain tissue, revealed a (peri-)nuclear signal and a strong neuritic signal of many neurons, especially on granule cells in the cerebellum, hippocampus, and olfactory bulb, as well as in the corpus callosum. Additionally, antinuclear antibody (ANA) titers of 1:12,800 and a lymphopenia were detected in blood tests. Further system clarification showed no suspicion of rheumatic or oncological disease. Anti-inflammatory treatment led to rapid and sustained improvement.

CONCLUSION

The present patient suffered from a probable "autoimmune depression" in the context of newly diagnosed multiple sclerosis with typical MRI and CSF pathologies, alongside mild concomitant latent systemic autoimmune process (with high-titer ANAs and lymphopenia) and unknown antineuronal antibodies. The case report illustrates that a depressive syndrome suggestive of primary idiopathic depressive disorder may be associated with an autoimmune brain involvement. The detection of such organic affective disorders is of high clinical relevance for affected patients, as it enables alternative and more causal treatment approaches.

Anti-Thyroid Peroxidase and Anti-Thyroglobulin Autoantibodies in the Cerebrospinal Fluid of Patients with Unipolar Depression

INTRODUCTION

The risk of developing depression is increased in patients with autoimmune thyroiditis. Autoimmune Hashimoto thyroiditis is diagnosed using the serum markers anti-thyroid peroxidase (TPO) and anti-thyroglobulin (TG) antibodies. In rare cases, patients with autoimmune thyroiditis can also suffer from the heterogeneous and ill-defined syndrome of Hashimoto encephalopathy. Biomarkers for Hashimoto encephalopathy or for any brain involvement of autoimmune thyroiditis are currently lacking. The aim of the present descriptive study was therefore to determine whether a subgroup of seropositive patients shows intrathecal anti-thyroid antibody synthesis in the cerebrospinal fluid (CSF).

PARTICIPANTS AND METHODS

Paired serum and CSF samples from 100 patients with unipolar depression were examined for anti-TPO and anti-TG antibodies using enzyme-linked immunosorbent assays. Antibody-specific indices (ASIs) were calculated for seropositive samples. These ASIs allow the differentiation between the brain-derived fraction of antibodies and antibodies which are passively diffused from the serum. ASIs >1.4 were assessed as positive for brain-derived antibodies. Additionally, for explorative evaluations, a stricter ASI limit of >2 was applied.

RESULTS

Anti-TPO antibodies were increased in the serum of 16 patients (16%); increased anti-TPO ASIs (>1.4) were detected in 11 of these patients (69%). Anti-TG antibodies in the serum were detected in three patients (3%), with two of them (67%) showing increased ASIs (>1.4). Overall, the authors found increased anti-thyroid antibodies in 17 of 100 patients (17%), with 13 out of 17 patients showing increased ASIs (76%; range 1.4-4.1). Choosing ASI levels of >2 led to positive findings in six out of 16 patients (38%) with anti-TPO antibodies in their serum but no increase in ASIs in three patients (0%) who were seropositive for anti-TG antibodies. The patients with elevated ASIs (N = 13) were younger than the ASI-negative patients (N = 87; p = 0.009); no differences were noted in the frequency of CSF, electroencephalography, and/or magnetic resonance imaging alterations.

DISCUSSION

A subgroup of seropositive patients showed intrathecal synthesis of anti-TPO and, more rarely, of anti-TG antibodies, which might be an indication of central autoimmunity in a subgroup of patients with unipolar depression. The confirmation of elevated ASIs as a biomarker for Hashimoto encephalopathy must await further studies. The relevance of the findings is limited by the study's retrospective and uncontrolled design.

Parkinsonian Syndrome with Frontal Lobe Involvement and Anti-Glycine Receptor Antibodies

Background: Atypical Parkinsonian syndromes with prominent frontal lobe involvement can occur in the 4R-taupathies progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Secondary forms of movement disorders may occur in the context of autoimmune encephalitis with antineuronal antibodies, such as anti-glycine receptor (anti-GlyR) antibodies, which are typically associated with Stiff-Person spectrum syndrome, or progressive encephalomyelitis with rigidity and myoclonus. Overlaps between neurodegenerative and immunological mechanisms have been recently suggested in anti-IgLON5 disease. In this case study, the authors describe a patient with a Parkinsonian syndrome with frontal lobe involvement and anti-GlyR antibodies. Case presentation: The patient presented was a 63-year-old female. Her symptoms had begun with insomnia at the age of 60, after which, since the age of 61, increasing personality changes developed, leading to a diagnosis of depression with delusional symptoms. Severe cognitive deficits emerged, along with a left-side accentuated Parkinsonian syndrome with postural instability. The personality changes involved frontal systems. Magnetic resonance imaging (MRI) showed low-grade mesencephalon atrophy. [¹⁸F]fluorodeoxyglucose positron emission tomography (FDG PET) depicted a moderate hypometabolism bilateral frontal and of the midbrain, while [¹²³I]FPCIT single-photon emission computed tomography (SPECT) revealed severely reduced dopamine transporter availability in both striata, indicating pronounced nigrostriatal degeneration. In addition, anti-GlyR antibodies were repeatedly found in the serum of the patient (max. titer of 1:640, reference: <1:20). Therefore, an anti-inflammatory treatment with steroids and azathioprine was administered; this resulted in a decrease of antibody titers (to 1:80) but no detectable clinical improvement. The cerebrospinal fluid (CSF) and electroencephalography diagnostics showed inconspicuous findings, and negative CSF anti-GlyR antibody results. Conclusion: The patient presented here was suffering from a complex Parkinsonian syndrome with frontal lobe involvement. Because of the high anti-GlyR antibody titers, the presence of an autoimmune cause of the disorder was discussed. However, since no typical signs of autoimmune anti-GlyR antibody syndrome (e.g., hyperexcitability, anti-GlyR antibodies in CSF, or other inflammatory CSF changes) were detected, the possibility that the anti-GlyR antibodies might have been an unrelated bystander should be considered. Alternatively, the anti-GlyR antibodies might have developed secondarily to neurodegeneration (most likely a 4-repeat tauopathy, PSP or CBD) without exerting overt clinical effects, as in cases of anti-IgLON5 encephalopathy. In this case, such antibodies might also potentially modify the clinical course of classical movement disorders. Further research on the role of antineuronal antibodies in Parkinsonian syndromes is needed.

Psychiatric Manifestation of Anti-LGI1 Encephalitis

Background: Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is typically characterized by limbic encephalitis, faciobrachial dystonic seizures and hyponatremia. The frequency with which milder forms of anti-LGI1 encephalitis mimic isolated psychiatric syndromes, such as psychoses, or may lead to dementia if untreated, is largely unknown. Case presentation: Here, the authors present a 50-year-old patient who had suffered from neurocognitive deficits and predominant delusions for over one and a half years. He reported a pronounced feeling of thirst, although he was drinking 10–20 liters of water each day, and he was absolutely convinced that he would die of thirst. Due to insomnia in the last five years, the patient took Z-drugs; later, he also abused alcohol. Two years prior to admission, he developed a status epilepticus which had been interpreted as a withdrawal seizure. In his serum, anti-LGI1 antibodies were repeatedly detected by different independent laboratories. Cerebrospinal fluid analyses revealed slightly increased white blood cell counts and evidence for blood–brain-barrier dysfunction. Magnetic resonance imaging showed hyperintensities mesio-temporally and in the right amygdala. In addition, there was a slight grey–white matter blurring. A cerebral [¹⁸F] fluorodeoxyglucose positron emission tomography (FDG-PET) examination of his brain showed moderate hypometabolism of the bilateral rostral mesial to medial frontal cortices. Treatment attempts with various psychotropic drugs remained unsuccessful in terms of symptom relief. After the diagnosis of probable chronified anti-LGI1 encephalitis was made, two glucocorticoid pulse treatments were performed, which led to a slight improvement of mood and neurocognitive deficits. Further therapy was not desired by the patient and his legally authorized parents. Conclusion: This case study describes a patient with anti-LGI1 encephalitis in the chronified stage and a predominant long-lasting psychiatric course with atypical symptoms of psychosis and typical neurocognitive deficits. The patient’s poor response to anti-inflammatory drugs was probably due to the delayed start of treatment. This delay in diagnosis and treatment may also have led to the FDG-PET findings, which were compatible with frontotemporal dementia (“state of damage”). In similar future cases, newly occurring epileptic seizures associated with psychiatric symptoms should trigger investigations for possible autoimmune encephalitis, even in patients with addiction or other pre-existing psychiatric conditions. This should in turn result in rapid organic clarification and—in positive cases—to anti-inflammatory treatment. Early treatment of anti-LGI1 encephalitis during the “inflammatory activity state” is crucial for overall prognosis and may avoid the development of dementia in some cases. Based on this case, the authors advocate the concept—long established in many chronic inflammatory diseases in rheumatology—of distinguishing between an “acute inflammatory state” and a “state of organ damage” in autoimmune psychosis resembling neurodegenerative mechanisms.

Cerebrospinal Fluid Findings of 36 Adult Patients with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a common neurodevelopmental disorder characterized by difficulties with social interaction, repetitive behavior, and additional features, such as special interests. Its precise etiology is unclear. Recently, immunological mechanisms, such as maternal autoantibodies/infections, have increasingly been the subject of discussion. Cerebrospinal fluid (CSF) investigations play a decisive role in the detection of immunological processes in the brain. This study therefore retrospectively analyzed the CSF findings of adult patients with ASD. CSF basic measures (white blood cell count, total protein, albumin quotient, immunoglobulin G (IgG) index, and oligoclonal bands) and various antineuronal antibody findings of 36 adult patients with ASD, who had received lumbar puncture, were compared with an earlier described mentally healthy control group of 39 patients with idiopathic intracranial hypertension. CSF protein concentrations and albumin quotients of patients with ASD were significantly higher as compared to controls (age corrected: p = 0.003 and p = 0.004, respectively); 17% of the patients with ASD showed increased albumin quotients. After correction for age and gender, the group effect for total protein remained significant (p = 0.041) and showed a tendency for albumin quotient (p = 0.079). In the CSF of two ASD patients, an intrathecal synthesis of anti-glutamate decarboxylase 65 (GAD65) antibodies was found. In total, more of the ASD patients (44%) presented abnormal findings in CSF basic diagnostics compared to controls (18%; p = 0.013). A subgroup of the patients with adult ASD showed indication of a blood-brain barrier dysfunction, and two patients displayed an intrathecal synthesis of anti-GAD65 antibodies; thus, the role of these antibodies in patients with ASD should be further investigated. The results of the study are limited by its retrospective and open design. The group differences in blood-brain barrier markers could be influenced by a different gender distribution between ASD patients and controls.

[Autoimmune encephalitis-Diagnostic and therapeutic decision tree from a psychiatric, neurological and ethico-legal point of view : Approach in cases of lack of ability to give consent and permissibility of compulsory treatment]

Patients with severe mental illnesses who are unable to give consent often need a rapid diagnosis and treatment but due to the psychiatric symptoms they often reject such measures. In the routine practice, the question arises to what extent the patient's expressed will should dictate the treatment steps and whether a decision against the patient's will is medically reasonable, ethically justifiable or even demanded and legally permissible. Autoimmune encephalitides, such as N‑methyl-D-aspartate receptor (NMDAR) encephalitis, have recently become important differential diagnoses due to their relative frequency, manifold symptoms and good treatability, as the underlying autoantibodies frequently cause organic psychoses. Using a complex case of a patient with NMDAR encephalitis, which was confirmed in the course of treatment, this article discusses the ethical and legal issues that are relevant in practice, from initial invasive diagnostics to involuntary confinement and compulsory treatment. The article discusses how physicians can respect the autonomy of such patients in the best way and how they can identify and resolve potential contradictions between the free will and the expressed will. Various convictions of physicians about autonomy and coercive treatment are discussed on the basis of the legal situation. Finally, it is discussed how the indications for a short compulsory treatment can be justified before the court of protection on the grounds of an analogy of autoimmune encephalitis to other severe brain diseases.

Novel Antineuronal Autoantibodies With Somatodendritic Staining Pattern in a Patient With Autoimmune Psychosis

BACKGROUND

Autoimmune encephalitis, such as anti-NMDA-receptor encephalitis, typically presenting with subacute onset of neuropsychiatric symptoms, can be detected by antineuronal autoantibodies or inflammatory changes in the cerebrospinal fluid (CSF), as well as pathological alterations in electroencephalography (EEG), magnetic resonance imaging (MRI), or [18F]fluorodeoxyglucose positron emission tomography (FDG PET). For patients with predominant psychotic symptoms, the term autoimmune psychosis was proposed. Here, the authors present the case of a patient with probable autoimmune psychosis associated with unknown antineuronal antibodies.

CASE PRESENTATION

A 18-year-old male patient with preexisting autism spectrum disorder developed a severe catatonic syndrome over 2.5 years. The MRI showed normal findings, the EEG depicted intermittent slowing, and the independent component analyses showed additional sharp spikes. However, FDG PET, the basic laboratory analysis and testing of the serum/CSF for well-characterized antineuronal autoantibodies were unsuspicious. The serum and CSF "tissue-based assay" using indirect immunofluorescence on unfixed murine brain tissue revealed antineuronal autoantibodies against an unknown epitope in granule cells in the cerebellum and to neurites of hippocampal interneurons with a somatodendritic staining pattern. The immunosuppressive treatment with high-dose glucocorticoids, plasma exchange, and rituximab led to partial improvement.

CONCLUSION

The patient probably suffered from autoantibody-associated autoimmune psychosis. The special features of the case were that the patient (1) presented with mostly inconspicuous basic diagnostics, except for the altered EEG in combination with the detection of CSF autoantibodies directed against a currently unknown epitope, (2) experienced an isolated and long-lasting psychotic course, and (3) had pre-existing autism spectrum disorder. The detection of a probable autoimmune pathophysiology in such cases seems important, as it offers new and more causal immunosuppressive treatment alternatives.

Autoimmune encephalitis as a differential diagnosis of schizophreniform psychosis: clinical symptomatology, pathophysiology, diagnostic approach, and therapeutic considerations

Primary schizophreniform psychoses are thought to be caused by complex gene-environment interactions. Secondary forms are based on a clearly identifiable organic cause, in terms of either an etiological or a relevant pathogenetic factor. The secondary or "symptomatic" forms of psychosis have reentered the focus stimulated by the discovery of autoantibody (Ab)-associated autoimmune encephalitides (AEs), such as anti-NMDA-R encephalitis, which can at least initially mimic variants of primary psychosis. These newly described secondary, immune-mediated schizophreniform psychoses typically present with the acute onset of polymorphic psychotic symptoms. Over the course of the disease, other neurological phenomena, such as epileptic seizures, movement disorders, or reduced levels of consciousness, usually arise. Typical clinical signs for AEs are the acute onset of paranoid hallucinatory symptoms, atypical polymorphic presentation, psychotic episodes in the context of previous AE, and additional neurological and medical symptoms such as catatonia, seizure, dyskinesia, and autonomic instability. Predominant psychotic courses of AEs have also been described casuistically. The term autoimmune psychosis (AP) was recently suggested for these patients. Paraclinical alterations that can be observed in patients with AE/AP are inflammatory cerebrospinal fluid (CSF) pathologies, focal or generalized electroencephalographic slowing or epileptic activity, and/or suspicious "encephalitic" imaging findings. The antibody analyses in these patients include the testing of the most frequently found Abs against cell surface antigens (NMDA-R, CASPR2, LGI1, AMPA-R, GABA_B-R), intracellular antigens (Hu, Ri, Yo, CV2/CRMP5, Ma2 [Ta], amphiphysin, GAD65), thyroid antigens (TG, TPO), and antinuclear Abs (ANA). Less frequent antineuronal Abs (e.g., against DPPX, GABA_A-R, glycine-R, IgLON5) can be investigated in the second step when first step screening is negative and/or some specific clinical factors prevail. Beyond, tissue-based assays on brain slices of rodents may detect previously unknown antineuronal Abs in some cases. The detection of clinical and/or paraclinical pathologies (e.g., pleocytosis in CSF) in combination with antineuronal Abs and the exclusion of alternative causes may lead to the diagnosis of AE/AP and enable more causal therapeutic immunomodulatory opportunities.

Anti-N-Methyl-D-Aspartate-Receptor Encephalitis: A 10-Year Follow-Up

BACKGROUND

Anti-N-methyl-D-aspartate-receptor (NMDA-R) encephalitis is an autoimmune disease of the brain first described in 2007. The aim of this paper is to present a 10-year follow-up case history.

CASE PRESENTATION

The authors present the case of a 39-year-old female patient who developed an anti-NMDA-R encephalitis in 2009 with predominant severe catatonic symptoms. Anti-inflammatory therapy led to the disappearance of catatonic symptoms and was discontinued during the course of the disease. After acute therapy, the patient achieved an almost full recovery presenting with ongoing discrete symptoms of sensory overload, subtle cognitive deficits, and fatigue/reduced energy levels. The follow-up investigation in 2019 showed inconspicuous findings in laboratory diagnostics and magnetic resonance imaging. Electroencephalography (EEG) analysis using independent component analysis detected left hemispherical spike-wave complexes and intermittent slowing. Regarding the sensory overload and reduced energy level, the patient benefited from low-dose neuroleptics (risperidone, amisulpride). In terms of sensory overload associated with experiences of panic, cognitive deficits and coping with the disease, she improved with cognitive behavioral therapy (CBT).

CONCLUSION

Anti-inflammatory treatment led to almost full recovery with persistent disappearance of catatonic symptoms; however, a dysexecutive syndrome led to ongoing relevant problems with good response to low-dose atypical neuroleptics and CBT. The patient had persistent EEG alterations that indicated continuing neuronal network instability. Therefore, the case demonstrates the importance of multidisciplinary outpatient treatment following acute therapy for anti-NMDA-R encephalitis in patients with ongoing psychiatric deficits. For the symptomatic treatment of executive dysfunctions, "classical" psychiatric treatment may be helpful in the course of the disease.

Psychiatric Presentation of Anti-NMDA Receptor Encephalitis

Background: Anti-N-methyl D-aspartate (NMDA) receptor encephalitis is an autoimmune condition characterized by neuropsychiatric symptoms, including epileptic seizures, movement disorders, autonomic instability, disturbances of consciousness, paranoia, delusions, and catatonia. Ovarian teratomas and viral infections, typically Herpes simplex viruses, have previously been demonstrated to precipitate anti-NMDA receptor encephalitis, but in many cases, the trigger remains unclear. The detection of anti-NMDA receptor antibodies in cerebrospinal fluid (CSF), in combination with other CSF, electroencephalography (EEG), or magnetic resonance imaging (MRI) abnormalities, typically leads to diagnostic clarification.

Case Presentation: We present the case of a 22-year-old female patient who developed an acute polymorphic psychotic episode 3 days after receiving a booster vaccination against tetanus, diphtheria, pertussis, and polio (Tdap-IPV). Her psychiatric symptoms were initially diagnosed as a primary psychiatric disorder. Her MRI, EEG, and CSF results were non-specific. Anti-NMDA receptor IgG antibodies against the GluN1 subunit were detected in her serum (with a maximum titer of 1:320), but not in her CSF. [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) showed pronounced relative hypermetabolism of her association cortices and a relative hypometabolism of the primary cortices, on the basis of which an anti-NMDA receptor encephalitis diagnosis was made, and treatment with a steroid pulse was initiated. The treatment led to fast and convincing clinical improvement with normalization of neuropsychological findings, considerable improvement of FDG-PET findings, and decreasing antibody titers.

Conclusion: The patient's psychiatric symptoms were most likely caused by anti-NMDA receptor encephalitis. Her polymorphic psychotic symptoms first occurred after she had received a Tdap-IPV booster vaccination. Although the vaccination cannot have caused the initial antibody formation since IgG serum antibodies were detected only 3 days after administration of the vaccine, the vaccine may have exerted immunomodulatory effects. MRI, EEG, and CSF findings were non-specific; however, FDG-PET identified brain involvement consistent with anti-NMDA receptor encephalitis. This case shows the importance of implementing a multimodal diagnostic work-up in similar situations. The negative CSF antibody finding furthermore fits to the hypothesis that the brain may act as an immunoprecipitator for anti-NMDA receptor antibodies.