SHM Converge Scientific Abstract ePoster Gallery-Iron Overload and B12 Deficiency Masking Autoimmune Polyglandular Syndrome Type 3b: A Diagnostic Challenge

Pdf Summary

This case describes a 58-year-old Hispanic man with autoimmune polyglandular syndrome type 3B (APS3B), a rare autoimmune disorder involving at least two endocrine diseases. He presented with 1.5 months of worsening fatigue, weakness, dyspnea on exertion, dizziness, poor appetite, nausea, and swelling of the face, hands, and legs. His history included chronic vitamin B12 deficiency with macrocytic anemia, recurrent blood transfusions for 15 to 20 years, type 2 diabetes mellitus, hypothyroidism, chronic myositis, and peripheral neuropathy. He had poor outpatient follow-up and had recently restarted metformin.<br /><br />Exam showed tachycardia, pallor, and edema. Workup supported autoimmune thyroiditis with positive TPO antibodies and pernicious anemia with positive intrinsic factor antibodies, confirming APS3B. Imaging showed cholelithiasis and mild splenomegaly, and echocardiogram showed preserved ejection fraction. Because of his long transfusion history, secondary iron overload was also a concern.<br /><br />During hospitalization, he received 3 units of packed red blood cells, with hemoglobin stabilized at discharge. Hematology recommended an intramuscular vitamin B12 replacement regimen: daily for 7 days, weekly for 4 weeks, then monthly maintenance. Metformin was stopped because his HbA1c was 6.8%, and no alternative diabetes medication was started. He was advised to follow up with his primary care physician and obtain an outpatient cardiac MRI to assess for iron-related cardiac dysfunction.<br /><br />The report emphasizes that APS3B can present with overlapping and misleading symptoms, such as anemia, neuropathy, fatigue, and edema, which may be mistaken for diabetes or nutritional deficiency alone. It also highlights the importance of screening patients with autoimmune thyroid disease for other autoimmune disorders, monitoring for transfusion-related iron overload, using metformin cautiously in B12-deficient patients, and ensuring long-term continuity of care.

Asset Subtitle

Katie Kyan

Meta Tag

Author List Debra Craig, Katie Kyan, Rosie Kumar

Category Clinical Vignettes

Concept Autoimmune Polyglandular Syndrome Type 3B

Concept Pernicious Anemia

Concept Autoimmune Hypothyroidism

Concept Secondary Iron Overload

Concept Vitamin B12 Replacement

Distinguished Non-Finalist

Presenter Organization California University of Science and Medicine

Presenting Author Katie Kyan

Track Adult

Keywords

autoimmune polyglandular syndrome type 3B

pernicious anemia

vitamin B12 deficiency

autoimmune thyroiditis

macrocytic anemia

intrinsic factor antibodies

transfusion-related iron overload

metformin

type 2 diabetes mellitus

chronic fatigue

Autoimmune Polyglandular Syndrome Type 3B

Pernicious Anemia

Autoimmune Hypothyroidism

Secondary Iron Overload

Vitamin B12 Replacement