An Unusual Presentation of New Onset Type 1 Diabetes Mellitus With Concurrent Addison’s Disease in an Adolescent Male

Introduction: Majority of children and adolescents diagnosed with Type 1 Diabetes Mellitus (T1D) present with the classic symptoms of polyuria, polydipsia and polyphagia, associated with hyperglycemia. Concurrent conditions at the time of T1D diagnosis may alter its presentation and potentially lead to challenges in diagnosis and management. Clinical Case: We present a 17-year-old male with worsening fatigue and unintentional weight loss for two months, then one week of emesis and abdominal pain. Initial work-up by his primary care provider showed sodium 125 mmol/L (133–145), potassium 5.7 mmol/L (3.5–5.1), HCO3 20 mmol/L (21–31), anion gap 13 mmol/L (9–18), random glucose 141 mg/dL (70–199). Due to hyponatremia and dehydration, he was sent to a local emergency room where he was found to be mildly hypotensive at 87/57 mmHg. He received intravenous fluids for hydration and was sent home. On out-patient follow up, he appeared well despite being hypotensive. His additional labs revealed a random glucose of 330 mg/dl and elevated HbA1C of 8.3% (4.4–5.6). His urine was positive for glucose but negative for ketones. He was admitted for further management of new onset diabetes. On admission, he was well appearing and in no acute distress. Blood pressure was 86/57 mmHg, heart rate was 109 bpm, and other physical exam findings were unremarkable. Although his hyperglycemia improved after initiation of insulin therapy, his electrolyte abnormalities persisted, raising suspicion for adrenal insufficiency. An ACTH stimulation test was performed, with both baseline and 60-minute cortisol levels low at 1 ug/dl and 0.9 ug/dl, respectively, confirming adrenal insufficiency. He responded well to glucocorticoid and mineralocorticoid replacement. His electrolytes and blood pressure normalized. Further testing confirmed elevated levels of Glutamic Acid Decarboxylase antibodies 0.19 nmol/L (less than 0.02), Islet Antigen 2 Antibodies: 3.38 nmol/L (less than 0.02), and 21-Hydroxylase antibodies, consistent with T1D with concomitant Addison’s disease (AD). Conclusion: About 0.5% of patients with T1D have AD, but the diagnosis of T1D typically precedes AD for several years, thus the coexistence of both autoimmune conditions at diagnosis is rare.