MKSAP Quiz: 3-week history of fatigue, nausea, and poor appetite
Patients need to be told they are overweight, study findsDrug adverse events affect patients' choices more than benefits
A 65-year-old woman is evaluated for a 3-week history of fatigue, nausea, and poor appetite. In the week before symptom onset, she had acute bronchitis with productive cough and fever. The patient has a 2-year history of osteoarthritis of the knees that requires intra-articular corticosteroid injections every 3 to 4 months; her last injection was 3 months ago. Her only other medication is acetaminophen.
On physical examination, the patient looks tired. Temperature is 37.5 °C (99.5 °F), blood pressure is 112/58 mm Hg, pulse rate is 92/min, respiration rate is 17/min, and BMI is 32. The patient has cushingoid features and central obesity. There are multiple ecchymoses on the upper and lower extremities. Decreased axillary and pubic hair is noted. There is bony hypertrophy and small effusions of the knees bilaterally but no evidence of warmth or erythema.
Laboratory studies:
Which of the following is the most likely cause of this patient's current symptoms?
A. Adrenal adenoma
B. Exogenous corticosteroids
C. Pituitary microadenoma
D. Primary adrenal insufficiency
MKSAP Answer and Critique
The correct answer is B) Exogenous corticosteroids. This item is available to MKSAP 15 subscribers as item 64 in the Endocrinology and Metabolism section.
This patient has central adrenal insufficiency. Use of systemic corticosteroids is the most common cause of central adrenal insufficiency, with supraphysiologic dosages of exogenous corticosteroids causing disruption of hypothalamic/pituitary adrenocorticotropic hormone (ACTH) production. Consequently, the adrenal cortex atrophies. When subsequently challenged by stress, the hypothalamus and pituitary gland are unable to stimulate adequate adrenal production of cortisol. This central effect of exogenous corticosteroids can occur after only 3 weeks of suppressive therapy. The patient appears to have developed Cushing syndrome as a result of chronic systemic exposure to the intra-articular injections of corticosteroids. Despite her cushingoid features, however, she has clinical and biochemical evidence of adrenal insufficiency. Her low-normal serum ACTH level and her partial response to cosyntropin stimulation indicate that she has central (secondary) adrenal insufficiency. Patients with adrenal insufficiency often decompensate during concurrent illnesses. Because the rest of her pituitary function is normal, another cause of her loss of ACTH secretion is unlikely.
An adrenal adenoma could cause a suppressed ACTH level, cushingoid features, and central obesity, but her symptoms suggest glucocorticoid deficiency. Furthermore, an adrenal adenoma would cause an elevated, not suppressed, cortisol level.
A nonfunctioning pituitary adenoma is extremely unlikely in light of the isolated ACTH deficiency and the timing of symptom onset—3 months after exogenous corticosteroid administration. A functioning pituitary adenoma might produce excessive ACTH, but in that case both the ACTH and cortisol levels would be elevated, not suppressed as they are in this patient.
Primary adrenal insufficiency (Addison disease) is typically associated with low cortisol production and elevated ACTH levels.
Key Point
- Secondary adrenal insufficiency due to exogenous corticosteroids may be associated with suppression of both adrenocorticotropic hormone and cortisol levels and with clinical findings of excess glucocorticoids.