6812 A Rare Case of Polyglandular Autoimmune Syndrome Type 3B Presenting with Unsteady Gait Due to Subacute Combined Degeneration of the Spinal Cord Associated with Pernicious Anemia

Abstract Disclosure: F. Mohammadrezaei: None. F. Sajid: None. C.A. Resta: None. J.G. Karam: None. A Rare Case of Polyglandular Autoimmune Syndrome Type 3B Presenting with Unsteady Gait due to Subacute Combined Degeneration of the Spinal Cord associated with Pernicious Anemia Background: The coexistence of Hashimoto's thyroiditis and pernicious anemia is well established and is recognized as Polyglandular Autoimmune Syndrome (PAS) Type 3B [1]. We describe a rare case of a patient presenting with subacute combined degeneration of the spinal cord leading to the diagnosis of PAS Type 3B. Case Presentation: A 37-year-old man with no known medical history presented to the Emergency Department after a fall in the subway station. On history, he complained of progressive bilateral lower extremity weakness of 10 months duration, necessitating assistance with ambulation, and significant weight gain, described as an increase in his pants size from 40 to 56. His physical examination was relevant for weight of 145kg, BMI of 46.5, normal motor strength and sensation of the upper extremities, decreased strength at 4 out of 5 of bilateral hip flexion and extension, and decreased vibration sensation of bilateral lower extremities. He could not fully stand or walk due to imbalance and weakness. Blood testing revealed a hemoglobin level of 11.4 gm/dl (14-18), MCV of 108.8 FL (80-94), a significantly low vitamin B12 at 89 pg/ml, and normal folate level. His TSH level was 9.26 MCIU/ML (0.39-4.08), with a free T4 of 0.74 ng/dl (0.8-1.8) and significantly elevated Thyroid Peroxidase Antibody titer at 4320 IU/ml (< 34.9). Intrinsic factor antibody and parietal cell antibody tests both came back elevated at 13.4 AU/mL (0.0-1.1) and 1.8 (<1.2), respectively. A head CT scan showed no acute pathology, but MRI spine with contrast revealed abnormal T2 hyperintensity, primarily affecting the lateral columns throughout the cervical and thoracic cord, likely indicative of subacute combined degeneration. The patient was diagnosed with autoimmune Hashimoto's thyroiditis, pernicious anemia, and subacute combined degeneration of the spinal cord due to vitamin B12 deficiency. He was treated with daily vitamin B12 1000mcg muscular injections, levothyroxine 75mcg orally daily (after ruling out adrenal insufficiency), and physical therapy. Conclusion: This case highlights the complexity of polyglandular autoimmune syndromes and the importance of recognizing atypical presentations early in the history of disease. Comprehensive evaluation and timely intervention are essential to mitigate the progression of these conditions and improve patients' quality of life. Reference: (1) Betterle C, Furmaniak J, Sabbadin C, Scaroni C, Presotto F. Type 3 autoimmune polyglandular syndrome (APS-3) or type 3 multiple autoimmune syndrome (MAS-3): an expanding galaxy. J Endocrinol Invest. 2023 Apr;46(4):643-665. Presentation: 6/1/2024