S5544 Autoimmune Collision: Severe Liver Injury in Thyroid Storm with Overlapping Grave's Disease and Autoimmune Hepatitis

Introduction: Thyroid storm is a multi-organ endocrine emergency implicated in liver injury and even rarely acute liver failure (ALF). We present a case of severe liver injury from thyroid storm in a patient with Grave’s disease. Case Description/Methods: A 44-year-old woman with hypertension, hyperthyroidism and reported prior hepatitis A infection was admitted with nausea/vomiting and jaundice. Her exam was notable for icterus and tachycardia. Initial lab work showed aspartate aminotransferase 1330, alanine aminotransferase 687, total bilirubin of 17.9 with direct of 13.1, with alkaline phosphatase of 186. Pertinent negative lab results included hepatitis A/B/C testing, ethanol/acetaminophen/ammonia levels, alpha-1-antitrypsin, ANA, ceruloplasmin, ferritin, anti-mitochondrial antibodies, cytomegalovirus IgM. IgG was >2500 and anti-smooth muscle antibody was mildly positive. international normalized ratio was 1.3, and platelets 32 with a suspected ITP component. She had elevated thyroid peroxidase antibody and TSH of <0.008 with elevated T3/T4. Given concern for thyroid storm the patient was treated with beta blocker, steroids, cholestyramine and methimazole. With treatment there was great improvement in thyroid tests and liver chemistries by the time of discharge. Discussion: Thyroid storm is a rare, life-threatening endocrine crisis marked by severe thyrotoxicosis and systemic involvement, including liver dysfunction driven by excess thyroid hormones, oxidative stress, hypoperfusion, and inflammatory cytokines. In thyroid storm liver enzyme elevations vary widely, usually with mild elevations but sometimes severe hepatic involvement. In autoimmune hepatitis (AIH), transaminase level can rise up to 1000 U/L. Graves' disease often presents with ophthalmopathy and pretibial myxedema. Most liver abnormalities improve with euthyroidism, but persistent enzyme elevation may indicate AIH. AIH is characterized by high IgG, ANA or SMA positivity. Overlapping both diseases is rare and a complicated diagnosis. Worsening liver function after thyroid control should prompt serologic testing and biopsy. Our patient had elevated IgG and positive Anti-SMA with the possibility of overlapping of both diseases. Thyroid storm due to overlap Graves’ disease and AIH is underreported and poorly understood. Most evidence is limited to case reports, with no standardized diagnostic or treatment guidelines. Differentiating drug-induced, thyrotoxic, and autoimmune liver injury remains a major challenge. Further research is needed to clarify mechanisms and optimize management.