Rare Case of Thyroid Storm Masked by Diabetic Ketoacidosis

Abstract

Abstract Introduction: Diabetic ketoacidosis can be triggered many other clinical conditions. In this case we describe uncommon presentation of diabetic ketoacidosis in the setting of thyroid storm. Clinical Case: An 82-year-old woman with history of type 2 diabetes treated with Insulin and Metformin presented with multiple falls preceded by fatigued and decreased oral intake for two weeks. On initial presentation, she was noted to have hyperglycemia and labs consistent high anion gap metabolic acidosis and positive serum and urine ketones suggesting diabetic ketoacidosis. Investigations were negative for any triggering infections. Diabetic ketoacidosis resolved with intravenous fluids and Insulin. However, patient remained consistently tachycardic. Repeated thyroid workup showed declining TSH (from 0.66 to 0.12 mIU/mL) (n: 0.270 - 4.200 mIU/mL), free T4 of 4.3 ng/dL (n: 0.9 - 1.7 ng/dL) and free T3 of 9.7 ng/dL (n: 79 - 165 ng/dL), thyroid peroxidase antibodies and thyroid stimulating immunoglobulin were both elevated of 293 IU/mL (n: <5.6 IU/mL) and 7.2 IU/L (n: <0.55 IU/L) respectively. Thyroid ultrasound showed several nodules in the isthmus and left lobe with multiple nodules with largest one measuring 1 X 2.3 cm. Treatment with Methimazole and Prednisone was initiated with good response. On follow up with endocrinology, repeated TSH was 28 mIU/mL and her Methimazole dose was reduced. Due to patient wishes of being conservative in management, no thyroid radioiodine uptake scan to evaluate the nodules. Conclusion: Literature review shows several similar case reports of newly diagnosed thyrotoxicosis manifested by DKA in known type 1 and type 2 diabetic and obscured by other confounding conditions including pericarditis, flu syndrome, psychosis and cellulitis ultimately delaying diagnosis and treatment of thyroid storm. Fortunately, none of these cases were associated with adverse outcome. By presenting this case we emphasis on including thyroid function test as part of initial work up of diabetic ketoacidosis to avoid any potential adverse outcomes.