Case Presentation: Autoimmune Polyglandular Syndrome Type 2 is a rare syndrome, with a prevalence of 1.4 to 4.5 per 100,000, distinguished by an association between autoimmune thyroid disease, Addison’s disease, and/or Type 1 diabetes mellitus (Wang, 2016). It can be particularly challenging to diagnose, especially in a situation where the endocrinopathies develop simultaneously leading to overlapping clinical presentations as seen in our case. A 41-year-old female with medical history of endometriosis, with recent hysterectomy, and Grave’s disease, in remission for over 8 years, presented to the emergency department after a syncopal episode. She reported sudden onset sweating and dizziness immediately prior to passing out. Notably, for the past 4 months after her hysterectomy, she had experienced a constellation of symptoms including tachycardia, daily nausea and emesis, dry skin, fatigue, muscle weakness, and an unintentional 20lb weight loss. On admission, she was found to have a blood pressure of 83/52 and a heart rate of 114, with an exam notable for weakness and thyroid bruit. Cardiogenic and orthostatic hypotension were ruled out as causes for syncope. Initial work up revealed her thyroid stimulating hormone to be <0.10mclU/nL, free thyroxine 2.45ng/dL, and free triiodothyronine of 7.84ng/dL. Thyroid ultrasound showed a diffusely enlarged heterogeneous and hypervascular thyroid consistent with recurrent Grave’s disease. She was treated with methimazole monotherapy, with increasing doses of up to 10mg twice daily, since her periodic hypotension prevented introduction of a beta blocker. Treatment improved her symptoms only mildly, and while severe thyrotoxicosis was thought to explain many of her complaints, her hypotension and gastrointestinal symptoms seemed atypical and remained unresolved. A morning cortisol was measured and found to be undetectable at <0.04µg/dL, and remained undetectable after a Cosyntropin stimulation test. Her ACTH was markedly elevated at 826.1pg/mL. This was consistent with primary adrenal insufficiency, or Addison’s disease, with her symptoms representing an acute adrenal crisis incited by her hysterectomy. She was started on both hydrocortisone and fludrocortisone with a dramatic improvement in her condition. She was discharged from the hospital in good condition with outpatient follow up with endocrinology.

Discussion: This case illustrates the interesting presentation of Autoimmune Polyglandular Syndrome Type 2 with two simultaneous endocrinopathies developing after a surgical procedure. Following the law of parsimony, it would have been reasonable to expect that just one disease should account for all her symptoms. However, our patient highlights the dangers of cognitive biases. The initial anchoring on her more overt and easily diagnosed Grave’s disease hindered the diagnosis of her Addison’s disease, a disease which is already notoriously difficult to diagnose due to its’ nonspecific symptoms, with less than 30% of females diagnosed in the first 6 months of presentation (Bleicken, 2010). Untreated, this patient could have progressed to develop shock or coma as a result of her adrenal crisis (Rathbun, 2020).

Conclusions: Recognizing the possibility of concurrent diseases and maintaining broad differentials becomes the key to diagnosing Autoimmune Polyglandular Syndrome Type 2 and ensuring that these patients receive appropriate and timely treatment for their conditions.