FRI562 Not JUST Severe Hypothyroidism: Recognizing Autoimmune Polyglandular Syndrome

Abstract Disclosure: S.R. Jafarian-Kerman: None. A. Razzeto: None. G. Saini: None. M. Siddiqui: None. M. Islam: None. D. Behman: None. M. Carson: None. Background: Recognizing Autoimmune Polyglandular Syndrome (AIPS) in a patient who has chronic hypothyroidism, specifically with a non-classic presentation, is challenging. Clinical Case: A woman in her 50’s with hypothyroidism presented with one week of progressive dizziness and weakness. Medications include levothyroxine 125 μg weekly (per the patient, her PCP started this dose 8 months ago based on lab results). On physical examination: BP 101/74 mmHg; HR 56 bpm; T: 98.1 F (36.7 C); RR: 23/min; O2 Sat: 98%. Skin: vitiligo. Lab results demonstrated TSH: 839.6 μIU/mL (0.5-4.5) from 0.28 one year ago, free T4: 0.15 ng/dL (0.4-4.5), phosphorus: 2.3 mg/dL (2.7-4.5), vitamin D: 17.4 ng/dL (>30). She was started on daily levothyroxine 125 μg and intravenous fluids. On day 3 of admission, Rapid Response was called for blood pressure 54/39 mmHg. Myxedema coma was unlikely as she lacked altered mental status, hypothermia, hypoventilation, hyponatremia, or hypoglycemia; CT head was normal. On the same day, hydrocortisone 100 mcg q8h started due to high suspicion of adrenal insufficiency given low normal cortisol [7.1 ug/dL (6-20)] and hypotension. Due to the history of hypothyroidism, vitiligo, and the new diagnosis of adrenal insufficiency, we suspected AIPS. two days later, primary adrenal insufficiency was established by a positive Cosyntropin stimulation test (1 hour cortisol of 14.8 ug/dL; not reaching >18 μg/dL), elevated ACTH 72 pg/mL (6-50), Aldosterone <1 ng/dL (3-16), and low DHEA of 52 ng/dL (345-2030). Other labs were as follow: normal FSH 85.7 mIU/mL (23-116), elevated PTH 153 pg/mL (16-77) which decreased to 62 pg/mL with vitamin D supplementation, normal Vitamin B12, and negative renin and intrinsic factor antibodies. A diagnosis of AIPS was established and she was discharged on levothyroxine, fludrocortisone, and hydrocortisone. Conclusion: AIPS is typically idiopathic and may affect endocrine organ systems either simultaneously or sequentially. The 3 classic patterns are: Type 1 (most common): younger women, presents with candidiasis, hypoparathyroidism, and Addison’s disease. Type 2: middle-aged women, Addison’s disease, autoimmune thyroid disease and/or Type 1 diabetes. Type 3: Type 1 diabetes, pernicious anemia, vitiligo or alopecia, and normal adrenal cortical function. This patient is unique in that she has characteristics of both type 1 and 3 AIPS, but not diabetes. In this case, the combination of hypotension even in the setting of profoundly undertreated hypothyroidism, prompted the expanded evaluation. While isolated hypothyroidism is common among our internal medicine patients, those with additional symptoms, or in this case unexplained hypotension, should be evaluated for AIPS. Presentation: Friday, June 16, 2023