A 38-year-old woman comes to the office with a 3-week history of weight loss, nausea, abdominal pain, and postural dizziness. She traveled to Thailand 6 months ago and has felt fatigued since then. Medical history is notable for moderate persistent asthma treated with an inhaled beta-2 agonist and inhaled corticosteroid. Over the last 2 years, the patient has had several asthma exacerbations requiring oral prednisone. She also has hypothyroidism treated with levothyroxine. The patient is married and is a stay-at-home mother. Blood pressure is 90/60 mm Hg and pulse is 96/min. Pharyngeal examination shows bilateral tonsillar enlargement. Skin examination shows increased pigmentation at the palmar creases and mucous membranes as well as a few patches of vitiligo. Initial laboratory testing shows mild hyponatremia and hyperkalemia with normal renal function. Complete blood count is normal, but differential shows moderate eosinophilia. Follow-up testing confirms a low 8 AM serum cortisol. Which of the following is the most likely cause of this patient's adrenal insufficiency?

Question

A 38-year-old woman comes to the office with a 3-week history of weight loss, nausea, abdominal pain, and postural dizziness.  She traveled to Thailand 6 months ago and has felt fatigued since then.  Medical history is notable for moderate persistent asthma treated with an inhaled beta-2 agonist and inhaled corticosteroid.  Over the last 2 years, the patient has had several asthma exacerbations requiring oral prednisone.  She also has hypothyroidism treated with levothyroxine.  The patient is married and is a stay-at-home mother.  Blood pressure is 90/60 mm Hg and pulse is 96/min.  Pharyngeal examination shows bilateral tonsillar enlargement.  Skin examination shows increased pigmentation at the palmar creases and mucous membranes as well as a few patches of vitiligo.  Initial laboratory testing shows mild hyponatremia and hyperkalemia with normal renal function.  Complete blood count is normal, but differential shows moderate eosinophilia.  Follow-up testing confirms a low 8 AM serum cortisol.  Which of the following is the most likely cause of this patient's adrenal insufficiency?

Quizplus · Accepted Answer

11ec25c8_d0ba_c2c2_bc81_33c7a65acc51_MD0003_00 This patient has several features of chronic primary adrenal insufficiency (PAI), including weight loss, abdominal pain, and fatigue. Hyperpigmentation is a common finding and is due to cosecretion of melanocyte-stimulating hormone with ACTH (both are derived from proopiomelanocortin), which is increased in response to cortisol deficiency. In addition, loss of mineralocorticoid production can cause hypotension, hyponatremia, and hyperkalemia. Eosinophilia and hyperplasia of lymphoid tissue (eg, tonsils) are common but nonspecific findings. Autoimmune adrenalitis is responsible for >90% of cases of PAI in developed countries. It is due to autoantibodies against adrenal enzymes that are responsible for corticosteroid synthesis. Autoimmune adrenalitis can occur as an isolated disorder or in association with other autoimmune syndromes (eg, primary hypothyroidism, vitiligo). (Choice A) Bilateral adrenal hemorrhage due to sepsis (eg, Neisseria meningitidis) can lead to PAI; however, this is less common, and the onset of clinical features is typically acute and dramatic. (Choice B) Hyperfunctioning adrenal tumors are a potential cause of hypercortisolism, but not PAI. Bilateral adrenal metastasis can cause PAI but this is a rare occurrence. (Choice D) Exogenous glucocorticoids can suppress pituitary secretion of ACTH and hypothalamic production of corticotropin-releasing hormone, leading to central (secondary) adrenal insufficiency. In contrast to PAI, secretion of melanocyte-stimulating hormone is not increased so patients do not display hyperpigmentation. Also, because mineralocorticoid production is controlled by the renin-angiotensin system, aldosterone levels are normal and hyperkalemia is not seen with central adrenal insufficiency. mineralocorticoid production (Choice E) PAI in HIV disease can be due to opportunistic infections (eg, cytomegalovirus, atypical mycobacteria, fungal infections) or inhibition of glucocorticoid synthesis by azole antifungal drugs. However, this patient has no apparent opportunistic infections, and her other autoimmune findings make autoimmune adrenalitis more likely. (Choice F) PAI due to tuberculosis (TB) is typically seen with miliary disease and is uncommon in developed countries. It is unlikely that this patient contracted TB and so rapidly developed manifestations of TB-induced PAI following her trip to Thailand 6 months ago. Educational objective: Autoimmune adrenalitis is the most common cause of primary adrenal insufficiency (PAI) in developed countries. The key differentiating features of PAI from central adrenal insufficiency are the hyperpigmentation and hyperkalemia seen in PAI. References: Diagnosis and treatment of primary adrenal insufficiency: an Endocrine Society Clinical Practice Guideline. (http://www.ncbi.nlm.nih.gov/pubmed/26760044) Tuberculosis of the adrenal gland: a case report and review of the literature of infections of the adrenal gland. (http://www.ncbi.nlm.nih.gov/pubmed/25165474)

A 38-Year-Old Woman Comes to the Office with a 3-Week