SUN-373 Breaking the Mold: Atypical Plasma Lactate and Ketone Elevations in Thyroid Storm

Abstract Disclosure: N. Bhuiya: None. R. Riachy: None. S. Shah: None. B. Kodali: None. Thyroid storm, a life-threatening manifestation of hyperthyroidism, carries a high mortality risk of 8% to 25%, emphasizing the importance of prompt diagnosis and intervention. While diagnostic tools like the Burch-Wartofsky Point Scale (BWPS) are widely used to assess disease severity, they may fail to account for atypical clinical and laboratory findings such as elevated plasma lactate and ketone levels, which can indicate a more severe disease course. We present the case of a 67-year-old male with a history of COPD, schizophrenia, and previous alcohol and cocaine abuse, but no prior thyroid disease, who presented with unintentional weight loss, palpitations, dyspnea, fatigue, poor oral intake, and occasional diarrhea. On examination, the patient was afebrile, hypertensive (151/84 mmHg), and tachycardic (150 bpm). Laboratory evaluation revealed TSH <0.010 uIU/ml, FT4 >5.6 ng/dl, FT3 >30 pg/ml, lactate 7.6 mmol/l, beta-hydroxybutyrate 4.13 mmol/l, troponin 876 ng/l, and a left ventricular ejection fraction (LVEF) of 15% on echocardiography. Despite a BWPS score of 35, consistent with impending thyroid storm, the biochemical profile suggested a more critical presentation. Initiation of methimazole, hydrocortisone, and propranolol resulted in marked clinical improvement. The patient subsequently underwent total thyroidectomy as definitive treatment during hospitalization. Follow-up echocardiography demonstrated normalization of LVEF to 60%, highlighting the reversibility of cardiac dysfunction with timely intervention. This case underscores the importance of incorporating atypical markers such as elevated lactate and ketones into the evaluation of hyperthyroidism severity. These findings may signify a more profound systemic impact of thyroid dysfunction, warranting heightened clinical vigilance. Early recognition and aggressive management of such cases are crucial to mitigating the risk of multi-organ failure and improving patient outcomes. Presentation: Sunday, July 13, 2025