MON-475 Autoimmune Polyglandular Syndrome Type 2 Presenting as Hashimoto's Thyroiditis and Primary Adrenal Insufficiency

Abstract Disclosure: M.D. Balina: None. J. Uy-Ho: None. H. Yao: None. S. Reburiano: None. E. David: None. F. Sorsona: None. Background: Autoimmune Polyglandular Syndromes (APS) are groups of 2 or more autoimmune endocrine and non-endocrine disorders that occur in discreet patterns. APS type 2, considered to be the most common form, is composed of primary adrenal insufficiency, type 1 diabetes mellitus, and autoimmune thyroid disease. Recognition of signs and symptoms of adrenal insufficiency before management of a diagnosed thyroid disease is of utmost importance. Case: This is a case of a 58-year-old female who was referred to endocrine service due to nodular goiter. Additional physical examination showed areas of hyperpigmentation, particularly sun-exposed areas, gums, and ears, which developed gradually over 3 years. On further probing, the patient reported brief episodes of lightheadedness, easy fatigability, and weight loss. She was initially diagnosed with hypothyroidism and tested positive for anti-thyroid peroxidase antibodies. She had mild hyponatremia with normal potassium and blood sugar levels. Further endocrine work-up showed low fasting 8 am serum cortisol levels at 1.99 mcg/dL associated with elevated ACTH of 1488 pg/mL. A tuberculosis infection was also ruled out. Ideally, 21-hydroxylase antibody testing should be done to diagnose autoimmune adrenal insufficiency. However, it was not available in our country. Anti-glutamic acid decarboxylase was negative. The adrenal CT scan result was also unremarkable. She was started on a physiologic dose of prednisone 5mg tab once daily and eventually given levothyroxine replacement for Hashimoto’s thyroiditis. On her latest follow-up, she reported significant improvement in daily activities and showed no signs of steroid excess. Conclusion: This case underscores the importance of the ability to diagnose clinical syndromes. Starting a patient on a thyroid hormone replacement for autoimmune thyroiditis without suspecting the presence of possible adrenal insufficiency will lead to worsening of the patient’s symptoms. Early recognition and intervention are crucial in preventing complications and improving the quality of life for affected individuals while also being able to anticipate the future development of associated disorders. Recommendation: Active screening for the development of type 1 diabetes mellitus in the future for our patient is recommended. Relatives should be advised of the early symptoms and signs of the principal component disease and should undergo screening every 3-5 years. Presentation: Monday, July 14, 2025