820 An Unusual Case of Post-Traumatic Brain Injury Kleine-Levin Syndrome with Anti-GAD-65 Autoantibodies

Abstract

Abstract Introduction Kleine-Levin Syndrome (KLS) is a rare clinical syndrome, and is precipitated by traumatic brain injury (TBI) in 9% of cases. An autoimmune component to KLS has previously been suggested. Autoantibody profiles in KLS are diverse and its overlap with autoimmune encephalitis is still not well described or understood. Here, a case of KLS in a patient with autoimmune diabetes with very high levels of serum autoimmune GAD-65 antibodies is presented. Report of case(s) A 36-year-old male Veteran with a history of alpha-thalassemia minor, prior history of insomnia with nightly sleep of 6 hours, prior history of mild OSA with AHI of 5.8 on PSG in 2018, sustained a mild TBI on 11/13/2019 after a 50-pound box fell on his head. CT head and cervical spine were normal. One week later, he developed recurrent episodes of hypersomnia, sleeping up to 80 hours continuously, waking briefly only to urinate or eat, with hyperphagia, irritability, and derealization present during episodes. One month after the TBI, he was diagnosed with Latent Autoimmune Diabetes in Adults (LADA) after blood glucose was found to be elevated at 566. Serum GAD-65 antibody level was very elevated at 10,594 U/mL (ref range: 0–5 U/mL), hemoglobin a1c was 7.7%, and insulin was started. Six months later, he was evaluated in the VA Sleep Clinic for continued hypersomnia, despite controlled diabetes. Neurological examination, MRI brain, and sleep-deprived EEG were normal. Cerebrospinal fluid testing was normal, with the exception of a CSF autoimmune encephalitis panel with a positive GAD-65 titer of 0.24 nmol/L (range <0.02 nmol/L) – non-diagnostic for autoimmune encephalitis. HLA-DQ1B status is pending. Conclusion Autoimmunity is an emerging topic of clinical significance in KLS. GAD-65 serum antibodies have both endocrine and neurologic significance, with high levels seen in autoimmune diabetes, encephalitis, stiff-person syndrome, and cerebellar ataxia. An autoantibody panel can be considered in patients with KLS, as the presence of autoimmune encephalitis may support the use of immunotherapy. Support (if any) Portland VA Research Foundation to Dr. Lim. The contents do not represent the views of the United States Government.