Severe multisystem organ dysfunction in an adolescent with simultaneous presentation of Addison's and Graves' disease

To report an unusual case of simultaneous presentation of Addison's and Graves' disease in an adolescent female previously diagnosed with type 1 diabetes (T1D) and Hashimoto's.

A 15-year-old female with T1D and hypothyroidism presented to the emergency department with altered mental state, fever, and left arm weakness for one day. Clinical work-up revealed coexistent new-onset adrenal insufficiency and hyperthyroidism. Her clinical course was complicated by severe, life-threating multisystem organ dysfunction including neurologic deficits, acute kidney injury, and fluid overload. Thyroidectomy was ultimately performed in the setting of persistent signs of adrenal crises and resulted in rapid clinical improvement.

Endocrinopathy should be included in the differential diagnosis of altered mental status. This case additionally illustrates the challenges of managing adrenal insufficiency in the setting of hyperthyroidism and supports the use of thyroidectomy in this situation.