LAUSR

Abstract: Background Delirium is one of the most prevalent conditions seen in older patients. Some of the newer known causes of delirium involve the body’s immune system attacking healthy brain cells, leading to inflammation of the brain known as autoimmune encephalitis. Method We herein report the case of an 80-year-old man presenting with progressive confusion, hallucinations, behavioral changes, insomnia, and weight loss. Results Despite negative findings on preliminary workup, further investigation revealed Contactin-associated protein-like-2-IgG (CASPR2-IgG) autoantibodies. With accurate diagnosis, he was able to receive the appropriate treatment with steroids that improved his condition. Conclusion Accurate diagnosis is essential for patients with autoimmune encephalitis to receive the treatment that can address the underlying problem. Too often, individuals with autoimmune encephalitis are misdiagnosed with psychiatric conditions which can lead to unnecessary psychotropic medication trials, psychiatric hospitalizations, and irreversible damage due to delays or lack of appropriate treatment.