Morvan's syndrome with anti contactin associated protein like 2 - voltage gated potassium channel antibody presenting with syndrome of inappropriate antidiuretic hormone secretion

Clinical characteristics of patients double positive for CASPR2 and LGI1-antibodies

OBJECTIVES

This study described the clinical characteristics of autoimmune neurological diseases with dual seropositive antibodies of CASPR2 and LGI1.

PATIENTS AND METHODS

Three patients, with antibodies targeting both CASPR2 and LGI1 (EUROIMMUN, FA 112d-1, Germany), hospitalized in Department of Neurology, Xuanwu Hospital, Capital Medical University from June 2016 to June 2019 were collected in this study. We summarized the clinical characteristics of patients with CASPR2 and LGI1 antibodies from a targeted literature review.

RESULTS

Three patients reported were all middle-aged and elderly male with diverse neurological symptoms, including seizures, psychological abnormalities, limb weakness and hyperhidrosis. Interestingly, three patients displayed three different clinical syndromes (isolated epilepsy, Morvan syndrome and limbic encephalitis, respectively). White blood cell and glucose in Cerebrospinal fluid (CSF) were normal and CSF for protein was slightly elevated. Electromyography (EMG) showed abnormal spontaneous firing in case 2. Brain magnetic resonance imaging (MRI) revealed bilateral hyper-intensity of the temporal lobe on T2 and FLAIR sequence in case 3. Cancer screening program of patient 2 showed thymoma. Cell based assay was positive in serum for both LGI1 and CASPR2 antibodies, while these antibodies were negative in CSF. They were treated with glucocorticoid or intravenous immunoglobulin (IVIG). Followed up for 6 months to 1 year, all patients got remission to different extent.

CONCLUSION

Through the detailed analysis of three patients, the combination of both antibodies contributes to a broad spectrum of neurological symptoms in the central, peripheral, and autonomic nervous systems. The patients with same antibodies can have different clinical syndromes. Early tumor screening and immunotherapy will improve the prognosis of the disease.

Analysis and discussion of the rare complication of autoimmune encephalitis: Two case reports

RATIONALE

Autoimmune encephalitis related to many antibodies against neuronal cell surface or synaptic proteins, it is increasingly recognized as the cause of a variety of neuropsychiatric syndromes.

PATIENT CONCERNS

The two pediatric cases were about autoimmune encephalitis with rare complication. One patient was a 11-year-old girl and was diagnosed with Voltage-Gated Potassium Channel complex (VGKC) antibody-mediated encephalitis with rhabdomyolysis; the other was also a 11-year-old girl and was diagnosed with anti- N-methyl-D-aspartate receptor (NMDAR) encephalitis.

DIAGNOSES

Both patients were diagnosed as autoimmune encephalitis with rare complication.

INTERVENTIONS

Intravenous methylprednisolone, oral prednisone and intravenous immunoglobulin was administered to both patients.

OUTCOMES

One patient was discharged after a half month's hospitalization; the other was finally with intestinal function failure, gradually developed multiple organ failure, and eventually died.

LESSONS

The pathogenic mechanism of autoimmune encephalitis associated with autoimmune disease is not fully understood, but may be related to a common immune pathological mechanism with variance in susceptibility caused by genetic or environmental factors.

Current Treatment Options for Peripheral Nerve Hyperexcitability Syndromes

PURPOSE OF REVIEW

Peripheral nerve hyperexcitability (PNH) syndromes are divided into primary and secondary groups based on the presence or absence of demonstrable peripheral nerve disease. In this review, we systematically evaluate the evidence for current therapies and supportive managements based on autoimmune, paraneoplastic, and genetic components in pathophysiology reported in the literature.

RECENT FINDINGS

Current therapy options are based on symptomatic management as well as focusing the underlying immune/genetic/paraneoplastic pathology by immunosuppressants, chemotherapy, and surgery. Further research is desired to provide treatment options geared specifically towards addressing PNH. Supportive care can also be an area for future research.

Morvan syndrome: a rare cause of syndrome of inappropriate antidiuretic hormone secretion

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) accounts for an important part of hyponatremia cases. The causes of SIADH can be detected almost always. As a rare disorder, Morvan Syndrome can be defined by the sum of peripheral nerve hyperexcitability, autonomic instability and neuropsychiatric features. Antibodies to voltage-gated potassium channels (Anti – VGKC-Ab) including contactin associated protein-like 2 antibodies (CASPR2-Ab) and leucine-rich glioma inactivated protein 1 antibodies (LGI1-Ab) were previously known for the potential association with this condition. We present a Morvan Syndrome in a patient who presented with various neuropsychiatric symptoms and SIADH.