SAT507 New Onset Graves’ Thyrotoxicosis Complicated by Hypokalemic Periodic Paralysis: A Late Sequela of COVID- 19 Infection

Disclosure: E. Askar: None. H. Basharat: None. L. Lotfi: None. Y. Jamal: None. Background: Thyrotoxic periodic paralysis (TPP)is a rare endocrine emergency identified by hypokalemia and ascending symmetrical paralysis of extremities. If left untreated, it can lead to cardiopulmonary collapse. There are cases in the literature highlighting that Covid-19 infection or Covid vaccination can cause hypokalemic periodic paralysis with or without thyroid dysfunction. To our knowledge, four cases of Covid induced TPP and three cases of TPP after Covid vaccination have been reported in the literature. In all cases, the patients developed TPP soon after (within two months) Covid-19 infection or vaccination. However, we describe a case of a young, healthy euthyroid male who developed TPP as an initial manifestation of new-onset Graves' disease after five months of Covid infection. Even though Covid-19 infection has been known to cause thyroid dysfunction, especially subacute thyroiditis, there have only been a few case reports of Covid induced Graves' disease presenting as TPP at initial diagnosis. Clinical Case: A 37-year-old Asian male with no past medical history presented to the emergency department with lower extremity paralysis, palpitations, tremors and diaphoresis one day prior to presentation. He was diagnosed with mild COVID 19 infection, five months prior to presentation. Since then, he has been having intermittent palpitations but did not have any other symptoms. Vital signs on admission revealed heart rate of 100 beats/min, respiratory rate of 16 breaths/min, blood pressure of 131/66 mmHg, temperature of 97.5°F and oxygen saturation of 98% on room air. Physical examination was significant for an anxious young male with tender enlarged thyroid gland. There was positive thyroid bruit. Pemberton sign was negative. Muscle strength of 1/5 in bilateral lower extremities with brisk deep tendon reflexes and tremors in both hands were noticed. Laboratory studies showed white blood cell count of 13.07 (3.80-10.50 x 109/L), serum potassium of 1.4 mmol/L (3.5-5.3) and thyroid stimulating hormone of <0.01 mIU/L (0.358-3.74), free thyroxine of 5.5 ng/dl (0.9-1.8), total Triiodothyronine of 438 ng/dl (80-200) and positive thyroid stimulating immunoglobin of 4.22 IU/l (0.00-0.55) confirming Graves' disease as a diagnosis causing thyrotoxicosis with periodic paralysis. Patient did not have any history of thyroid disease with no available previous thyroid function tests. Patient was admitted to intensive care unit. Judicious repletion of potassium was done and he was started on propranolol 40 mg daily and methimazole 30 mg daily that lead to resolution of his paralysis and hyperthyroid symptoms. Conclusion: Here we report a case of new onset Graves' disease with TTP after COVID 19 increasing the likelihood that Covid 19 is a direct cause of new onset autoimmune thyroid illness. More studies are required to identify the mechanism and to confirm if the relationship is causal. Presentation Date: Saturday, June 17, 2023