Acute limbic encephalitis: a new entity?

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.

Case report of anti-N-methyl-D-aspartate receptor encephalitis in a middle-aged woman with a long history of major depressive disorder

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disease involving antibodies against the NR1 subunits of NMDARs. The disease shows variable clinical presentation, and involves new-onset acute psychotic symptoms, making it difficult to differentiate from major depressive disorder with psychotic symptoms. Potential associations between this autoimmune disorder and onset or progression of major depressive disorder remains unclear.

CASE PRESENTATION

We present a rare case of a patient who had both major depressive disorder and anti-NMDAR encephalitis and in whom the encephalitis initially went undetected. The patient had been suffering from depressive disorder for more than 6 years without any treatment, when she was hospitalized for new-onset psychotic symptoms. She was initially diagnosed only with major depressive disorder with psychotic symptoms, but antipsychotics did not alleviate symptoms and the patient's psychiatric course began to fluctuate rapidly. Anti-NR1 IgG autoantibodies were detected in cerebrospinal fluid, and the combination of immunotherapy and antipsychotics proved more effective than antipsychotics alone. The patient was then also diagnosed with anti-NMDAR encephalitis.

CONCLUSIONS

Our case suggests that clinicians should consider anti-NMDAR encephalitis when a patient with depressive disorder shows sudden fluctuations in psychiatric symptoms. It also highlights the need for research into possible relationships between anti-NMDAR encephalitis and major depressive disorder.

'Medusa head ataxia': the expanding spectrum of Purkinje cell antibodies in autoimmune cerebellar ataxia. Part 2: Anti-PKC-gamma, anti-GluR-delta2, anti-Ca/ARHGAP26 and anti-VGCC

Serological testing for anti-neural autoantibodies is important in patients presenting with idiopathic cerebellar ataxia, since these autoantibodies may indicate cancer, determine treatment and predict prognosis. While some of them target nuclear antigens present in all or most CNS neurons (e.g. anti-Hu, anti-Ri), others more specifically target antigens present in the cytoplasm or plasma membrane of Purkinje cells (PC). In this series of articles, we provide a detailed review of the clinical and paraclinical features, oncological, therapeutic and prognostic implications, pathogenetic relevance, and differential laboratory diagnosis of the 12 most common PC autoantibodies (often referred to as 'Medusa head antibodies' due their characteristic somatodendritic binding pattern when tested by immunohistochemistry). To assist immunologists and neurologists in diagnosing these disorders, typical high-resolution immunohistochemical images of all 12 reactivities are presented, diagnostic pitfalls discussed and all currently available assays reviewed. Of note, most of these antibodies target antigens involved in the mGluR1/calcium pathway essential for PC function and survival. Many of the antigens also play a role in spinocerebellar ataxia. Part 1 focuses on anti-metabotropic glutamate receptor 1-, anti-Homer protein homolog 3-, anti-Sj/inositol 1,4,5-trisphosphate receptor- and anti-carbonic anhydrase-related protein VIII-associated autoimmune cerebellar ataxia (ACA); part 2 covers anti-protein kinase C gamma-, anti-glutamate receptor delta-2-, anti-Ca/RhoGTPase-activating protein 26- and anti-voltage-gated calcium channel-associated ACA; and part 3 reviews the current knowledge on anti-Tr/delta notch-like epidermal growth factor-related receptor-, anti-Nb/AP3B2-, anti-Yo/cerebellar degeneration-related protein 2- and Purkinje cell antibody 2-associated ACA, discusses differential diagnostic aspects, and provides a summary and outlook.

Analysis of a child who developed abnormal neuropsychiatric symptoms after administration of oseltamivir: a case report

Background

Neuropsychiatric side effects of oseltamivir occur occasionally, especially in infants and young patients, but nothing is known about possible contributory factors.

Case presentation

We report a case of a 15-year-old Japanese female with influenza infection who developed abnormal psychiatric symptoms after administration of standard doses of oseltamivir. She had no history of neurological illness, had never previously taken oseltamivir, and had not developed psychiatric reactions during previous influenza infection. Her delirium-like symptoms, including insomnia, visual hallucinations, and a long-term memory deficit, disappeared after cessation of oseltamivir and administration of benzodiazepine. Detailed assessment was performed, including neurological examination (electroencephalogram, brain magnetic resonance imaging, single photon emission computed tomography with 99mTc-ethyl cysteinate dimer and with ¹²³I-iomazenil, cerebrospinal fluid analysis and glutamate receptor autoantibodies), drug level determination and simulation, and genetic assessment (OAT1, OAT3, CES1, Neu2).

Conclusions

Abnormal slowing in the electroencephalogram, which is characteristic of influenza-associated encephalopathy, was not observed in repeated recordings. The serum level determination of active metabolite Ro 64-0802 determined at 154 h after final dosing of oseltamivir was higher than the expected value, suggesting delayed elimination of Ro 64-0802. Thus, abnormal exposure to Ro 64-0802 might have contributed, at least in part, to the development of neuropsychiatric symptoms in this patient. The score on Naranjo’s adverse drug reaction probability scale was 6. Mutation of c.122G > A (R41Q) in the sialidase Neu2 gene, increased CSF glutamate receptor autoantibodies, and limbic GABAergic dysfunction indicated by SPECT with ¹²³I-iomazenil were found as possible contributory factors to the CNS side effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-015-0393-2) contains supplementary material, which is available to authorized users.

Anti-N-methyl-d-aspartate receptor encephalitis: review of clinical presentation, diagnosis and treatment

Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a form of encephalitis occurring primarily in women and associated with antibodies against NR1 or NR2 subunits of the NMDA receptor. As a potentially treatable differential for symptoms and signs seen in neurology and psychiatric clinics, clinicians practising across the lifespan should be aware of this form of encephalitis. Common clinical features include auditory and visual hallucinations, delusions, behavioural change (frequently with agitation), impaired consciousness, motor disturbance (ranging from dyskinesia to catatonia), seizures, and autonomic dysfunction. We present a review of the literature on the disorder, including its clinical presentation, differential diagnosis, epidemiology, treatment and prognosis.

Paraneoplastic limbic encephalitis resembling acute herpetic encephalitis

Introduction. Paraneoplastic limbic encephalitis (PLE) is a rare disorder that typically follows a chronic or subacute course of personality changes, memory loss, seizures, and hallucinations. Early diagnosis is difficult and characteristic symptoms can be mimicked by a variety of conditions. We present a case of PLE, initially presenting as acute herpetic encephalitis. Case Presentation. A 56-year-old male was admitted for evaluation of acute onset headache, fever, and confusion. On neurological examination he was confused with MMSE score of 15/30. CSF analysis revealed marked lymphocytic pleocytosis. A possible diagnosis of acute herpetic encephalitis was rendered and patient was treated with acyclovir. CSF PCR was negative. Cranial MRI revealed bilateral hyperintense lesions in medial temporal lobes with contrast enhancement. Despite treatment with acyclovir patient was deteriorated; thus, a paraneoplastic syndrome was suspected. Chest CT showed a right paratracheal lymph node mass, while a biopsy revealed neuroendocrine lung cancer. Auto antibodies to Hu were also detected. The patient was treated with steroids and chemotherapy. Six months later, he had complete tumour remission and marked neurological improvement. Discussion. PLE can rarely invade acutely, being indistinguishable from herpetic encephalitis. Inclusion of PLE in the differential diagnosis of acute encephalitis is of great clinical significance.

Brain perfusion SPECT in limbic encephalitis associated with autoantibody against the glutamate receptor epsilon 2

OBJECTIVES

The aim of this study was to elucidate the single-photon emission computed tomography (SPECT) pattern at the acute stage of disease in non-herpetic limbic encephalitis (NHLE) patients associated with the N-methyl-D-aspartate-type glutamate receptor epsilon 2 (GluR ϵ2) autoantibody using Z-score imaging system (eZIS) analyses.

METHODS

Brain magnetic resonance imaging (MRI) and brain perfusion SPECT using technetium-99 ethyl cysteinate dimer ((99m)Tc-ECD) were performed in eight patients with NHLE (5 men and 3 women; mean age 48.8±22 years) within 20days after clinical onset.

RESULTS

All patients had various clinical limbic-associated symptoms and no evidence of herpes simplex infection or systemic malignancies. Two of eight patients showed abnormally hyperintense lesions on diffusion-weighted images and significant hyperperfusion in ipsilateral cerebral cortex on eZIS analysis, whereas other patients showed normal MRI findings and significant hypoperfusion in one or both sides of the limbic and paralimbic areas.

CONCLUSION

We suggest that (99m)Tc-ECD SPECT study using eZIS analyses may be helpful to detect the neuronal dysfunction, particularly in NHLE patients without abnormal MRI findings.

Limbic encephalopathy and central vestibulopathy caused by mefloquine: a case report

Mefloquine is a 4-methanolquinoline anti-malarial that in recent years has fallen out of favor for use as chemoprophylaxis against infection with chloroquine-resistant Plasmodium falciparum malaria owing in part to growing concerns of side effects and potential neurotoxicity. Despite over 20 years of licensed use, the pathophysiological mechanisms underlying mefloquine's neuropsychiatric and physical side effects and the clinical significance of the drug's neurotoxicity have remained poorly understood. In this report, an adverse reaction to mefloquine chemoprophylaxis is described characterized by prodromal symptoms of anxiety with subsequent development of psychosis, short-term memory impairment, confusion and personality change accompanied by complaints of disequilibrium and vertigo, with objective findings of central vestibulopathy. It is posited that these effects represent an idiosyncratic neurotoxic syndrome of progressive limbic encephalopathy and multifocal brainstem injury caused by the drug. This case provides insights into the clinical significance of mefloquine neuronal gap junction blockade and neurotoxicity demonstrated in animal models, points to recommendations for the management of affected patients including diagnostic considerations and appropriate referrals, and highlights critical implications for the continued safe use of the medication.

PET/CT in the evaluation of anti-NMDA-receptor encephalitis: What we need to know as a NM physician

Anti N-methyl-D-aspartate receptor encephalitis (ANMDARE), also known as limbic encephalitis (LE), is a treatable rare disorder characterized by personality changes, irritability, depression, seizures, memory loss and sometimes dementia. It is classified under paraneoplastic syndrome (PNS) and produces antibodies against NR1 and NR2 subunits of glutamate aspartate receptor. It is thought to be closely related with malignancies like small cell lung cancer, ovarian teratoma and Hodgkin's lymphoma, apart from testis, breast and rarely gastric malignancies. Non-paraneoplastic encephalitis cases are the ones with no detectable malignancy and may be triggered by severe infection. As nuclear medicine physicians, we must be aware of the diverse presentation of ANMDARE or LE and should include a whole body positron emission tomography / computed tomography (PET/CT) and not just brain PETCT during imaging. We describe the first case of PET/CT in an idiopathic ANMDARE Indian adolescent girl.

Detection of DNA of six human herpesviruses in the cerebrospinal fluid of immunocompetent non-herpetic acute limbic encephalitis patients

In order to determine whether six other human herpesviruses, aside from herpes simplex virus, are associated with non-herpetic acute limbic encephalitis in immunocompetent individuals, real-time PCR was used to detect the DNA of herpesviruses in CSF collected from 61 patients with this form of encephalitis. Five of the human herpesviruses tested were not detected in any of the 61 CSF samples. EBV DNA was detected in one CSF sample. The EBV DNA-positive patient was a 36-year-old woman who presented with fever, headache, mild somnolence, and the typical neuroimaging findings.

Diagnostic and pathogenic significance of glutamate receptor autoantibodies

Autoantibodies against glutamate receptors, first reported in Rasmussen encephalitis, have been observed in other focal epilepsies, central nervous system ischemic infarcts, transient ischemic attacks, sporadic olivopontocerebellar atrophy, systemic lupus erythematosus, and paraneoplastic encephalopathies. The detection of glutamate receptor autoantibodies is not useful in the evaluation of Rasmussen encephalitis but may be a biomarker for brain ischemia, and it is helpful in diagnosing certain paraneoplastic encephalopathies. Passive transfer of glutamate receptor autoantibodies from patients with systemic lupus erythematosus or paraneoplastic encephalopathy suggests that glutamate receptor autoantibodies can actively contribute to neurologic dysfunction.

Central nervous system infections of herpesvirus family

Herpesviruses are one of the most common groups of pathogens causing central nervous system infections in humans. They mostly cause encephalitis, meningitis, or myelitis in immunocompetent and immunocompromised patients. Children, adults, and the elderly can all be affected. Although contrast-enhanced CT is more widely used for diagnosis, contrast-enhanced MR imaging combined with diffusion-weighted imaging is superior to CT in the detection of early changes and the real extent of the disease, and in assessing prognosis and monitoring response to antiviral treatment. More sophisticated techniques, such as MR spectroscopy and perfusion imaging, can aid in the differential diagnosis of herpesvirus infections from other tumoral, demyelinating, and ischemic processes.

[Non-paraneoplastic limbic encephalitis revealed by anterograde amnesia]

INTRODUCTION

Limbic encephalitis is a syndrome, most commonly paraneoplastic, related to an often undiagnosed cancer of unpredictable prognosis. Neurological symptoms are progressive for a few weeks before stabilizing.

CASE

We report a case of limbic encephalitis in a 56-year-old man, revealed by anterograde amnesia. The diagnosis was suggested after magnetic resonance imaging (MRI) showed bilateral hippocampal lesions, with signals that were hypointense in IR sequences and hyperintense in FLAIR. The non-neoplastic causation was suggested by an array of clinical, laboratory, imaging, and therapeutic arguments. After five years of follow-up, no neoplasia has been found.

DISCUSSION

This case provides the opportunity for a comparison of the radiologic, imaging, and neurologic findings related to bilateral lesions of the hippocampus.

Neuropathological studies of patients with possible non-herpetic acute limbic encephalitis and so-called acute juvenile female non-herpetic encephalitis

OBJECTIVE

This study was to clarify the neuropathological findings of non-herpetic acute limbic encephalitis (NHALE) and so-called acute juvenile female non-herpetic encephalitis (AJFNHE).

METHODS

We examined three rare autopsied cases consisting of probable one NHALE and two AJFNHLE. For comparison, we also studied 10 autopsied cases of hippocampal sclerosis mainly caused by anoxia.

RESULTS

In NHALE, neuronal loss with gliosis and microglia/macrophage infiltrations were mainly seen in the CA1 areas in the hippocampus. However, there were no apparent anoxic neuronal changes in the remaining neurons in the CA1, and astrocyte proliferations and microglia/macrophage infiltrations were also observed in the claustrum, while these were mildly present in the basal ganglia. In AJFNHE, pathological findings differed from those of NHALE with regard of the absence of limited pathology in the limbic system, microglia/macrophages widely infiltrated the brain including the hippocampal areas and mild lymphocytic infiltrations were observed in the subarachnoid spaces as well as in the parenchyma.

CONCLUSIONS

The pathomechanism of NHALE and AJFNHE is obscure and autoimmune theory is proposed, however we must collect and examine many autopsied cases in order to clarify the pathomechanism.

Chronic myoclonia of subcortical origin with antiglutamate receptor antibodies

We report a 10-year-old girl with chronic nonprogressive continuous myoclonia with mild muscle weakness and dissociated sensory impairment of the ipsilateral side of myoclonic jerks. Irregular myoclonic jerks continuously appeared in the right upper limb. The jerk-locked back averaging of electroencephalographic activity failed to show any activity preceded by the muscle contraction. Magnetic resonance imaging of the brain and cervical spine revealed no abnormal findings. Single photon emission computed tomography showed an increased blood perfusion in the left thalamus. (18)F-deoxyglucose-positron emission tomography (PET) also showed a slight high density in the posterior region of the left thalamus. Antiglutamate receptor epsilon2 and delta2 antibodies were detected in the serum and cerebrospinal fluid. The patient's symptoms have now been stable with clonazepam treatment for 2 years. The left thalamus was suspected to have been the region at least partly responsible for the patient's symptoms.

A patient with encephalitis associated with NMDA receptor antibodies

BACKGROUND

A 34-year-old woman presented with headache, feverish sensation and anxiety, rapidly followed by homicidal ideation, aggressive agitation, seizures, hypoventilation, hyperthermia and prominent autonomic instability requiring intubation and sedation. She developed episodes of hypotension and bradycardia with periods of asystole lasting up to 15 seconds. Upon weaning off sedation, her eyes opened but she was unresponsive to stimuli. There was muscle rigidity, frequent facial grimacing, rhythmic abdominal contractions, kicking motions of the legs, and intermittent dystonic postures of the right arm.

INVESTIGATIONS

Routine laboratory testing, toxicology screening, studies for autoimmune and infectious etiologies, brain MRI scan, lumbar puncture, electroencephalogram, whole-body CT scan, abdominal ultrasound, paraneoplastic and voltage-gated potassium channel antibody serologies, analysis of N-methyl-D-aspartate receptor antibodies.

DIAGNOSIS

Paraneoplastic encephalitis associated with immature teratoma of the ovary and N-methyl-D-aspartate receptor antibodies.

MANAGEMENT

Intensive care, mechanical ventilation, antiepileptics, laparotomy and left salpingo-oophorectomy, corticosteroids, plasma exchange, intravenous immunoglobulin, cyclophosphamide, physical therapy, and chemotherapy.

Limbic encephalitis: a cause of temporal lobe epilepsy with onset in adult life

Limbic encephalitis (LE) was described in the 1960s as a clinical-pathological syndrome in adults. Initially, the paraneoplastic form was the center of interest. An increasing number of diagnostically valuable autoantibodies in patients' sera (and cerebrospinal fluid) have been identified. Lately, the impact of non-paraneoplastic LE cases has been acknowledged. In the serum of some of these patients, antibodies against voltage-dependent potassium channels (VGKC antibodies) have been detected. The characteristic MRI course of LE patients has recently been described in detail: hippocampal swelling and T2/FLAIR signal increase are early findings. After a few months, the swelling regresses, followed by hippocampal atrophy with continuous signal increase. A general consensus on formal diagnostic criteria for all LE subsyndromes has not yet been reached. This article proposes such diagnostic criteria and formulates suggestions for treatment.

Neuropsychological symptoms in paraneoplastic disorders

Neuropsychological symptoms may rarely be part of a paraneoplastic neurological syndrome, mainly as limbic encephalitis. As the tumour will not be known in most patients upon presentation to the neurologists, state-of-the art diagnosis including the use of anti-neuronal antibodies and FDG-PET is essential for adequate management of these patients.

A case of acute cerebellitis accompanied by autoantibodies against glutamate receptor delta2

A 13-year-old boy presented with a six-day history of headache and gradually developed severe meningeal irritation symptoms. Brain magnetic resonance imaging revealed left cerebellar swelling and obstructive hydrocephalus. Then he showed transient ataxia, but recovered without any sequelae soon after high dose steroid therapy. IgG type of autoantibodies against glutamate receptor delta2 (GluRdelta2) were detected in the serum, but not in the cerebrospinal fluid in his early clinical course. It was suggested that autoantibodies against GluRdelta2 might not have injured the tissue due to the immunological action, but might be induced as a consequence of cerebellar damage. Early steroid treatment for acute cerebellitis might have been effective to prevent the progress of the disease and improve the prognosis.

Acute encephalitis with refractory, repetitive partial seizures: case reports of this unusual post-encephalitic epilepsy

We report on three acute encephalitis patients with refractory, repetitive partial seizures (AERRPS). All three suffered acute febrile episodes associated with status epilepticus, which necessitated high-dose barbiturate therapy under artificial ventilation for several weeks. Electroencephalography (EEG) revealed a predominance of diffuse epileptiform discharges initially, subsequently developing into periodic bursts of these discharges. Reduction of the barbiturate dosage resulted in clinical and subclinical partial seizures appearing repetitively in clusters. Prolonged fever persisted for 2-3 months, even several weeks after normalization of cell counts in the cerebrospinal fluid. The EEG showed an improvement after resolution of this fever, and seizures became less frequent, although still intractable. Oral administration of high-dose barbiturate and benzodiazepines were partially effective during the acute phase, and a barbiturate dependency, lasting for years, was noted in one patient. Steroid administration was effective in stopping the febrile episodes in one patient, with concurrent improvement in seizure control. Magnetic resonance imaging showed enhancement of bitemporal cortical areas in one patient, and high signal intensity on T2 weighted image in the bilateral claustrum in another patient. Diffuse cortical atrophy appeared within two months after the onset of encephalitis in all patients. The evolution of the seizures and EEG findings suggested a high degree of cortical excitability in AERRPS. In this report, we propose a tentative therapeutic regimen for seizure control in this condition. We also hypothesize that a prolonged inflammatory process exists in the cerebral cortex with AERRPS, and may be pivotal in the epileptogenesis.

Autoimmune limbic encephalitis in 39 patients: immunophenotypes and outcomes

BACKGROUND

About 40% of patients with limbic encephalitis do not have detectable CNS antibodies. Some of these patients have immune-mediated limbic encephalitis, but their frequency is unknown.

AIMS

(1) To determine the spectrum of limbic encephalitis identified on clinical grounds in a single institution, and compare it with that in patients referred for antibody analysis. (2) To correlate clinical outcomes with the cellular location of the autoantigens.

METHODS

Prospective clinical case studies. Immunohistochemistry with rat brain, live hippocampal neurones, HeLa cells expressing Kv potassium channels and immunoblot.

RESULTS

In 4 years, 17 patients were identified in the Hospital of the University of Pennsylvania, Philadelphia, USA, and the serum or CSF samples of 22 patients diagnosed elsewhere were also studied. 9 of our 17 (53%) patients had antibodies to known neuronal antigens (paraneoplastic or voltage gated potassium channels (VGKCs)) and 5 (29%) to novel cell-membrane antigens (nCMAg) typically expressed in the hippocampus and sometimes in the cerebellum. Considering the entire series, 19 of 39 (49%) patients had antibodies to known antigens, and 17 (44%) to nCMAg. Follow-up (2-48 months, median 19 months) was available for 35 patients. When compared with patients with antibodies to intraneuronal antigens, a significant association with response to treatment was found in those with antibodies to cell-membrane antigens in general (VGKC or nCMAg, p = 0.003) or to nCMAg (p = 0.006).

CONCLUSIONS

(1) 82% of patients with limbic encephalitis prospectively identified on clinical grounds had CNS antibodies; (2) responsiveness to treatment is not limited to patients with VGKC antibodies; (3) in many patients (29% from a single institution), the autoantigens were unknown but were found to be highly enriched in neuronal cell membranes of the hippocampus; and (4) these antibodies are associated with a favourable outcome.