Adrenal Insufficiency: Hidden Mimicker With Other Autoimmune Disease Potentials

Background: Adrenal insufficiency has various nonspecific symptoms, which are often overlooked until the patient presents with a life-threatening adrenal crisis. Our patient presented during the COVID19 pandemic, which further blurred our diagnostic sense. Clinical Case: A 26-year-old female presented with sudden intractable non-bloody non-bilious vomiting occurring every 30 minutes along with sharp epigastric pain radiating to her back, dizziness, and extreme fatigue for the last 2 days. She had similar but milder episodes in the past 2–3 years as well and endorsed unintentional weight loss for the same duration. She had been extensively investigated previously but was misdiagnosed as gastroparesis or anxiety and was prescribed medications for the same (pantoprazole, sucralfate, and Lexapro). On presentation this time, she was hypotensive and tachycardic but partially responsive to IV fluids. Her BMI was 15.31 and the abdominal exam was benign. Her basic labs showed Na 125, K 4.9, Calcium 10.5, Cr 1, WBCs 9K, lipase 8, normal LFTs, TSH 6.96, Free T4 1.18. Infectious workup was done and the patient was started on empirical antibiotics. Negative infectious workup, hypotension partially responsive to IV fluid, along with hyponatremia and borderline high potassium level prompted us to check Cortisol. We found Cortisol of 1.3(very low for the degree of her illness). ACTH stimulation test with 250mcg IV cosyntropin showed cortisol of 1.3 at 30 minutes and 1.1 at 60 minutes confirming the diagnosis of adrenal insufficiency. Further workup revealed a positive 21 hydroxylase antibody and ACTH level of 322 (high due to lack of negative feedback to the pituitary). She was comprehensively tested for other autoimmune diseases which showed positive Endomysial IgA and Tissue Transglutaminase antibodies indicating asymptomatic celiac disease. She improved drastically after starting hydrocortisone. TSH was repeated in 3 months which was normal. Conclusion: The onset of chronic adrenal insufficiency is very gradual with vague presentation and it may go undetected unless illness or other stress precipitates acute crisis as in our patient. Since autoimmune adrenalitis is the most common cause of primary adrenal insufficiency (Addison’s disease), patients with a confirmed diagnosis should also undergo workup for other autoimmune diseases.