A Case of Thyroid Eye Disease Revealed During Secondary Adrenal Insufficiency

Introduction: Thyroid eye disease (TED) or Graves’ orbitopathy (GO) is an autoimmune disease of the retro-orbital tissues. GO is mostly associated with hyperthyroidism in 90% of patients; however, it may coexist with hypothyroid conditions in 5% of cases. Clinical Case: A 56-year-old male with a past medical history of autoimmune diseases including hypothyroidism and Ulcerative Colitis on chronic steroid therapy presented to the emergency department with nausea, fatigue, weight loss, and muscle weakness. The patient stated that his glucocorticoids were abruptly discontinued a month prior to his current presentation. On examination, vitals were stable. The patient was somnolent with a depressed mood. He had bilateral periorbital edema and bilateral eyeball protrusion, left more pronounced than right. Extraocular muscle movement revealed a delay in the lateral movement of the left eye causing double vision on exam. He had no starring look or lid lag. The thyroid gland was normal in size and contour. Initial Laboratories revealed a white blood cell count of 6.7 K/mcL (4-10 K/mcL) with 18% eosinophil count (0-5%). Cortisol at 8 AM was 2.9 mcg/dL (4.3 -22.4 mcg/dl). The patient was managed for secondary adrenal insufficiency and restarted immediately on Prednisone. A review of a recent CT scan of the head revealed bilateral proptosis with no signs of compressing lesions. Further thyroid studies revealed TSH of 2.9 mcIU/mL (0.3-3.7 mcIU/mL), free T4 of 0.8 ng/dL (0.75-2.0 ng/dL), free T3 of 1.6 ng/dL (2.4-4.2 ng/dL), TPO antibodies <0.3 IU/mL (0.0-9.0 IU/mL) and TSH receptor antibodies 0.90 IU/L (reference range <1.75 IU/L). The patient was then diagnosed with Hypothyroid Grave’s ophthalmopathy with negative antibodies given the evidence of proptosis on CT and exam revealing extraocular muscle movement restriction causing diplopia. The patient had a unique presentation of TED with hypothyroidism and asymmetric ophthalmic signs that were only manifested after the patient discontinued the prednisone and therefore unmasking the underlying disorder. Fortunately, in June of 2020, the US Food and Drug Administration (FDA) approved Teprotumumab (an insulin-like growth factor 1 [IGF-1] receptor inhibitor) for the treatment of Graves’ orbitopathy based on the findings from two 24-week trials comparing teprotumumab with placebo in 171 patients with active, moderate-to-severe orbitopathy. (1) Our patient was started on Levothyroxine along with Prednisone and referred for ophthalmology evaluation for possible qualification for Teprotumumab treatment. Conclusion: Clinician awareness of the unusual presentations of TED would allow for early recognition and prevention of progression, especially with the recently approved treatment modality. References: (1) Teprotumumab for Thyroid-Associated Ophthalmopathy. Smith TJ Et al. N Engl J Med. 2017;376(18):1748.