Treatment of Anti-GAD65 Autoimmune Encephalitis With Methylprednisolone

Immunotherapy in a case of low titre GAD65 antibody-associated spectrum neurological disorders

We present a rare case of low titre GAD65 antibody-associated autoimmune encephalitis and status epilepticus in a young woman. She initially presented with left arm dystonic movements, contractures and status epilepticus. Due to the concern of autoimmune encephalitis and seizures, the patient received intravenous immunoglobulin empirically. After the detection of low serum GAD65 antibodies, the patient underwent immunomodulation therapy with significant improvement. This case demonstrated that in autoimmune encephalitis, it is important to monitor serum GAD65 antibodies levels and consider immunotherapy, despite mildly elevated serum levels. The patient's history of left arm dystonic movements without impaired awareness may have been due to limb dystonia, a presenting symptom of stiff person syndrome (SPS), despite SPS more commonly affecting axial muscles. This case further demonstrates that GAD65 antibody-related syndromes can manifest with different neurological phenotypes including co-occurrence of epilepsy with possible focal SPS despite low GAD65 antibodies titres.

Susac Syndrome and Role of Therapeutic Plasma Exchange: A Case Report

Susac syndrome is a relatively uncommon autoimmune disease that predominantly affects young females, with the highest incidence between the third and fourth decade of life, presenting classically with encephalopathy, various CNS dysfunctions, visual impairment due to retinal artery occlusion, and hearing loss. Despite treatment options, such as glucocorticoid steroids, intravenous immunoglobulin, methotrexate, azathioprine, mycophenolate mofetil, or rituximab, some patients with Susac syndrome remain refractory to therapy. We present a case report of a 38-year-old female with refractory Susac syndrome who was treated successfully with plasmapheresis.

Co-occurrence of Anti-GAD65 Syndrome, Type 1 Diabetes Mellitus, and Focal Seizures With Impaired Awareness

Glutamic acid decarboxylase (GAD) is an intracellular enzyme found in the presynaptic end of nerve terminals that functions to synthesize ​​gamma-aminobutyric acid (GABA) via decarboxylation. Autoantibodies to the GAD65 isoform have been found in high levels in neurological disorders including stiff person syndrome (SPS), autoimmune encephalitis, and refractory epilepsy. Low levels of anti-GAD65 have also been noted in type 1 diabetes mellitus. We present the unusual case of a woman with a longstanding history of focal seizures with impaired awareness and type 1 diabetes mellitus who was found to have extremely high titers of anti-GAD65 and clinical presentation suggestive of stiff person syndrome. This case highlights the increasing significance of autoimmune etiologies within neurologic disorders, as well as the importance of maintaining a high index of suspicion for rare anti-GAD65 syndromes. Although uncommon and with an unclear pathophysiology, we discuss the importance of establishing SPS diagnostic criteria to facilitate timely diagnosis and quickly direct patient management towards immunotherapy.

A Sharp Rise in Autoimmune Encephalitis in the COVID-19 Era: A Case Series

BACKGROUND

Autoimmune encephalitis was very rare prior to the current pandemic. A sharp rise in cases has been observed from March to August of 2022 in Los Angeles. Such an increase, especially with certain types of antibodies, may point toward the possibility of post-infectious autoimmune encephalitis. While review articles on autoimmune encephalitis during this pandemic have been published, a sharp rise in one geographic area within a short period of time has not been documented yet.

AIMS

To report an alarming increase in autoimmune encephalitis with mostly positive glutamic acid decarboxylase (GAD) and/or voltage-gated potassium channel (VGKC) antibodies over six months during 2022 in Downtown Los Angeles.

MATERIAL AND METHODS

This is an observational case series from one neurocritical care practice in Downtown Los Angeles. Autoimmune encephalitis antibody panels were sent to patients with altered mental status or neurologic deficits of unclear etiology from March to August of 2022.

RESULTS

Of the 29 patients tested, 12 reports came back positive. Ten had positive GAD and/or VGKC antibodies, one had a positive myelin oligodendrocyte glycoprotein antibody, and one had a positive leucine-rich glioma-inactivated 1 protein antibody; a 41% positive rate.

CONCLUSIONS

This observation has important implications: (1) We may be entering an era of heightened autoimmune encephalitis. (2) These occurrences may be post-infectious in nature at this point of the pandemic. (3) Mostly GAD and VGKC antibodies have been identified (10 of them), which may point toward a new direction of research from a molecular mimicry standpoint. (4) To benefit patients, clinicians need to be aware of such disease manifestations and increase testing; resources must be increased to improve test availability and shorten turnaround time; and treatment, which is expansive, must be made widely available for these potentially reversible diseases.

Autoimmune meningoencephalitis associated with anti-glutamic acid decarboxylase antibody following COVID-19 infection: A case report

Anti-glutamic acid decarboxylase (Anti-GAD) are associated with various neurologic condition; but no meningitis has been reported with it, so far. Evidence demonstrates the associated of autoimmune meningoencephalitis with COVID-19 infection. Here, we report a 44-year-old female with progressive loss of consciousness with anti-GAD65 meningoencephalitis 1 month after COVID-19 infection.