Case Report: Limbic encephalitis following treatment with durvalumab for small-cell lung cancer.

Background: Durvalumab is an immune checkpoint Inhibitor (ICIs) that is used in the treatment of malignant tumors, such as lung cancer and melanoma. ICIs are associated with immune-related adverse events including autoimmune encephalitis, although both paraneoplastic phenomena and ICI treatment may lead to autoimmunity. Case presentation: We describe a 72-year old male patient with small-cell lung cancer, who during adjuvant treatment with Durvalumab developed GABABR1 and GAD65 antibodies and both diabetes and autoimmune limbic encephalitis. Because he was followed prospectively as part of a treatment study, we had access to repeated serum samples and cognitive assessments over time prior to developing encephalitis and diabetes, in addition to later assessments. A high titer of GABABR1 antibodies appeared early, while GAD65 antibodies appeared later with a lower titer in parallel with the development of diabetes. As he subsequently developed clinical signs of encephalitis, verified by EEG and brain MRI, he also had CSF GABABR1 antibodies. Durvalumab was discontinued and steroid treatment with subsequent plasmapheresis were started, resulting in reduction of both CSF and serum antibody levels. Clinical signs of encephalitis gradually improved. Conclusion: This case illustrates the importance of being aware of possible serious autoimmune adverse reactions, including neurological syndromes such as encephalitis, when treating patients with high risk of para-neoplasia with ICIs. In addition, the case shows the development of autoantibodies over time.

Confusion and Hallucination in a Geriatric Patient. Pitfalls of a Rare Differential: Case Report of an Anti-LGI1-Encephalitis.

Background: Confusion and hallucinations in geriatric patients are frequent symptoms and typically associated with delirium, late-life psychosis or dementia syndromes. A far rarer but well-established differential in patients with rapid cognitive deterioration, acute psychosis, abnormal movements and seizures is autoimmune encephalitis. Exemplified by our case we highlight clinical and economic problems arising in management of geriatric patients with cognitive decline and psychotic symptoms. Case Presentation: A 77-year-old female caucasian patient with an unremarkable medical history was hospitalized after a fall in association with diarrhea and hyponatremia. Upon adequate therapy, disorientation and troubled short-term memory persisted. Within a week the patient developed visual hallucinations. Basic blood and urine samples and imaging (cranial computed tomography and magnetic resonance imaging) were unremarkable. With progressive cognitive decline, amnestic impairment, word finding difficulty and general apathy, psychiatric and neurologic expertise was introduced. Advanced diagnostics did not resolve a final diagnosis; an electroencephalogram showed unspecific generalized slowing. Extended clinical observation revealed visual hallucinations and faciobrachial dystonic seizures. A treatment with anticonvulsants was initiated. Cerebrospinal fluid ultimately tested positive for voltage-gated potassium channel LGl1 (leucine-rich-inactivated-1) antibodies confirming diagnosis of autoimmune anti-LGI1 encephalitis. Immediate immunotherapy (high-dose glucocorticoids and administration of intravenous immunoglobulin G) led to a rapid improvement of the patient's condition. After immunotherapy was tapered, the patient had one relapse and completely recovered with reintroduction of glucocorticoids and initiation of therapy with rituximab. Conclusion: Rapidly progressive dementia in geriatric patients demands a structured and multidisciplinary diagnostic approach. Accurate management and financially supportable care is a major issue in rare diseases such as anti-LGI1-encephalitis. Education and awareness about autoimmune encephalitis of all physicians treating a geriatric population is important in order to involve expertise and establish treatment within reasonable time.

Electroencephalographic Evaluation for Early Diagnosis of Limbic Encephalitis.

Limbic encephalitis (LE) is an inflammation of structures of limbic system. It may be an autoimmune disease or secondary to a neoplasia. Onset is subacute within a few weeks and clinical presentation is characterized by behavioral changes, psychiatric symptoms, short-term memory loss, and epileptic seizures. Diagnosis is typically set after a magnetic resonance imaging (MRI) scan, revealing hyperintensity in limbic structures on T2, fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) sequences or detection of antineuronal antibodies; EEG aspecific alterations on temporal areas usually match with MRI and laboratory findings. Specific diagnostic criteria are still under debate. We describe a case presenting with EEG alterations before MRI ones.A 36-year-old woman came to our attention for a first generalized tonic-clonic seizure, several episodes of likely epigastric auras and memory loss. Her clinical history was unremarkable. Neurological examination and brain MRI with gadolinium were normal. Electroencephalographic (EEG) recordings showed theta activity and sharp elements in frontotemporal regions. Therapy with levetiracetam 1000 mg/day was started, but she had another generalized seizure and episodes of epigastric auras increased to 10 per day. After 2 months, another cerebral MRI revealed areas of swelling and signal alteration in deep left temporal areas, especially in hippocampal and parahippocampal gyrus. A spectroscopic evaluation revealed decreased N-acetyl aspartate peak and increased choline and myo-inositol peaks in left frontotemporal areas. These findings were consistent with LE. Cerebrospinal fluid (CSF) analysis was normal; viral serology and onconeuronal antibodies on CSF and blood were negative. Patient was treated with high-dosage steroids, with improvement in memory, epileptic seizures and auras. A third MRI revealed no signal alterations.In conclusion, the clinical picture initially did not meet accepted diagnostic criteria for LE. Effective steroid therapy was consequently delayed. With this case report we would emphasize diagnostic relevance of EEG alterations early in suspected LE in order to start immunosuppressive therapy as soon as possible.

[Workup and treatment of autoimmune encephalitis]. / Udredning og behandling afautoimmun encephalitis.

Autoimmune encephalitis with antibodies against neuronal surface antigens is diagnosed with increasing frequency in recent years. If treated early and aggressively, these conditions often respond favourably to immunotherapy. We describe the clinical features, diagnosis and treatment of the two most common types of autoimmune encephalitis with antibodies against the N-methyl-D-aspartate receptor or the leucine-rich glioma-inactivated 1 protein. Together, these two conditions comprise 80% of the autoimmune encephalitis cases diagnosed in Denmark. Autoimmune encephalitides with rare antibodies are also summarized.

Voltage-gated potassium channel antibody-associated limbic encephalitis.

We are emphasising the importance of considering a rare diagnosis, voltage-gated Potassium channel antibody-associated limbic encephalitis, in an 80-year-old gentleman who presented with memory impairment, seizure and hyponatraemia. He was found to have high titre of voltage-gated potassium channel antibodies in his serum. He was given high-dose steroids and he responded biochemically and clinically with marked improvement in symptomatology.

EBV limbic encephalitis after allogenic hematopoietic stem cell transplantation.

The clinical and radiological presentations of Epstein-Barr virus (EBV) encephalitis are pleomorphic, but a common and characteristic finding is an increased T2-weighted signal in the bilateral thalami and basal ganglia. We report here a case of post-transplant acute limbic encephalitis (PALE) syndrome that was possibly related to EBV infection. Six weeks after hematopoietic stem-cell transplantation, the patient developed confusion and anterograde amnesia. Brain magnetic resonance imaging (MRI) was performed and revealed bi-hippocampal and amygdala signal abnormalities. The technetium-99m single-photon emission computed tomography ((99m)Tc SPECT) imaging confirmed bilateral limbic structural involvement. The clinical, biological and radiological presentations were consistent with a diagnosis of EBV-induced PALE syndrome. To our knowledge, this is the first described case of PALE syndrome possibly related to EBV infection.

Hypothermia in VGKC antibody-associated limbic encephalitis.

Voltage-gated potassium channel antibody (VGKC-Ab)-associated limbic encephalitis (LE) is a recently described syndrome that broadens the spectrum of immunotherapy-responsive central nervous system disorders. Limbic encephalitis is typically characterised by a sub-acute onset of disorientation, amnesia and seizures, but the clinical spectrum is not yet fully defined and the syndrome could be under-diagnosed. We here describe the clinical profile of four patients with VGKC-Ab-associated LE who had intermittent, episodic hypothermia. One of the patients also described a prodrome of severe neuropathic pain preceding the development of limbic symptoms. Both of these novel symptoms responded well to immunosuppressive therapy, with concurrent amelioration of amnesia/seizures.