Board Review: Internal Medicine
A 48-year-old female presents to the ED with generalized fatigue. Patient has a past medical history of HTN, HLD, Crohn’s Disease. She admits to some nausea, vomiting, and dizziness as well. Vital signs: T 98.3F, HR 73, BP 70/50, RR 18, Pulse Ox 100% on room air. Blood glucose is 35. Exam is unremarkable. Patient admits that she stopped taking all of her medications three days ago because she ran out. Medication list shows hydrochlorothiazide, atorvastatin, and prednisone. Which lab test would be most helpful in making the diagnosis?
Answer: C. Cortisol
The patient’s history is concerning for adrenal insufficiency secondary to abrupt cessation of daily corticosteroids. While all of these tests will be helpful in ruling out the differential diagnosis, cortisol will be the most useful in making the correct diagnosis. The three categories of adrenal insufficiency are as follows:
Primary Adrenal Insufficiency:
Causes- Addison’s Disease, Congenital Adrenal Hyperplasia, Medications (Etomidate, Ketoconazole, etc.)
Labs: High CRH, High ACTH, low cortisol, low aldosterone
Secondary Adrenal Insufficiency:
Causes- Pituitary Tumors, Sheehan Syndrome, Trauma
Labs: High CRH, Low ACTH, low cortisol, normal aldosterone
Tertiary Adrenal Insufficiency:
Causes- Hypothalamus tumors, chronic steroid use
Labs: Low CRH, low-normal ACTH, low cortisol
If labs demonstrate a low cortisol level it is helpful to obtain an ACTH level. An ACTH stimulation test is useful in differentiating between secondary and tertiary adrenal insufficiency. Treatment of these patients is immediate volume resuscitation and IV glucocorticoids. Typically IV hydrocortisone is recommended, however, prednisone/prednisolone/dexamethasone can be used if needed. Ultimately, patient’s will require mineralocorticoid replacement as well, however, this is a much slower onet. These patients will require continuous steroid replacement and should be admitted to the hospital.
Idrose A (2020). Adrenal insufficiency. Tintinalli J.E., & Ma O, & Yealy D.M., & Meckler G.D., & Stapczynski J, & Cline D.M., & Thomas S.H.(Eds.), Tintinalli's Emergency Medicine: A Comprehensive Study Guide, 9e. McGraw-Hill. https://accessemergencymedicine.mhmedical.com/content.aspx?bookid=2353§ionid=190079291
Pazderska, A., & Pearce, S. H. (2017). Adrenal insufficiency - recognition and management. Clinical medicine (London, England), 17(3), 258–262. https://doi.org/10.7861/clinmedicine.17-3-258