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Zorluk: Çok zorMedical History Evaluation

A 48-year-old man is evaluated in the endocrinology clinic for a 4-month history of progressive central weight gain, easy bruising, and proximal muscle weakness. He reports significant difficulty climbing stairs. His medical history includes asthma and HIV. His medications include a fluticasone-salmeterol inhaler, which he has used at a stable dose for three years, and an antiretroviral regimen consisting of bictegravir, emtricitabine, and tenofovir alafenamide, which has kept his viral load undetectable for five years. He explicitly denies using oral, topical, or injectable corticosteroids. His blood pressure is 158/96158/96 mmHg. Physical examination reveals a dorsocervical fat pad, facial plethora, and wide violaceous striae on his abdomen.

Laboratory studies show:
Morning serum cortisol: 0.80.8 μ\mu g/dL (Normal: 5−255 - 25 μ\mu g/dL)
Plasma ACTH: <5< 5 pg/mL (Normal: 10−6010 - 60 pg/mL)

Which of the following elements of his recent medical history most likely explains his clinical presentation and laboratory findings?

  1. A
    Heavy, unrecorded consumption of alcoholic beverages
  2. B
    Chronic utilization of his current antiretroviral therapy regimen
  3. Initiation of oral therapy for onychomycosisCevap
  4. D
    Covert use of anabolic-androgenic steroids
  5. E
    Recent cessation of over-the-counter nonsteroidal anti-inflammatory drugs

Cevap

The correct answer is the initiation of oral therapy for onychomycosis, which introduces a potent CYP3A4 inhibitor that interacts with his inhaled corticosteroid.
The correct answer identifies the initiation of oral therapy for onychomycosis as the trigger for this patient's condition. This patient presents with classic Cushing syndrome (central adiposity, violaceous striae, proximal weakness) coupled with profoundly low endogenous cortisol and ACTH levels. This laboratory pattern definitively points to exogenous glucocorticoid administration suppressing the hypothalamic-pituitary-adrenal (HPA) axis. Although the patient denies taking systemic steroids, he is on a fluticasone inhaler. Fluticasone has high glucocorticoid receptor affinity but typically low systemic bioavailability due to extensive first-pass metabolism by hepatic and intestinal cytochrome P450 3A4 (CYP3A4). Itraconazole, a common oral treatment for onychomycosis, is a potent CYP3A4 inhibitor. Taking these medications concurrently leads to massive systemic accumulation of fluticasone, resulting in iatrogenic Cushing syndrome and severe secondary adrenal suppression. Careful review of the medical history for seemingly unrelated recent prescriptions is critical for diagnosing complex pharmacological interactions.

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1
Identify the clinical syndrome.
The patient exhibits classic signs of Cushing syndrome (weight gain, proximal weakness, violaceous striae, facial plethora, hypertension).
Recognizing the syndrome guides the interpretation of the subsequent endocrinologic laboratory workup.
2
Interpret the laboratory findings (cortisol and ACTH).
Both morning serum cortisol and plasma ACTH are profoundly suppressed.
Low ACTH with low endogenous cortisol indicates that the hypothalamic-pituitary-adrenal (HPA) axis is suppressed by an exogenous source of glucocorticoids. Endogenous Cushing syndrome (e.g., pituitary adenoma, adrenal tumor) would present with elevated cortisol.
3
Correlate the exogenous steroid source with the medication history.
The patient denies oral/injectable steroids but is taking inhaled fluticasone.
Standard doses of inhaled fluticasone rarely cause severe systemic Cushing syndrome unless its first-pass metabolism is impaired.
4
Evaluate for pharmacokinetic drug-drug interactions.
Fluticasone is metabolized extensively by the hepatic and intestinal enzyme CYP3A4.
If CYP3A4 is inhibited, systemic absorption and accumulation of fluticasone skyrocket, leading to iatrogenic Cushing syndrome.
5
Identify the source of CYP3A4 inhibition in the history.
Oral therapy for onychomycosis (e.g., itraconazole) is a classic, potent inhibitor of CYP3A4.
Adding itraconazole to a patient on fluticasone precipitates sudden, severe exogenous hypercortisolism.

Anahtar Kavram

Iatrogenic Cushing syndrome with secondary adrenal suppression can be precipitated by drug-drug interactions, classically when a potent CYP3A4 inhibitor (like itraconazole) is prescribed alongside an inhaled corticosteroid (like fluticasone).
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Medical History Evaluation

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