A 22 y/o male presents to the ED with weakness and BP = 84/37. Sodium = 132, potassium = 5.9. Patient is lightheaded. ACTH is elevated at baseline. Then, Cosyntropin 250 mcg is given by IM injection. At 60 mins, serum cortisol = 10 mcg/dL. Which of the following etiologies is most likely for this presentation?

Correct Answer: C

Rationale: The presentation and lab findings (low BP, hyponatremia, hyperkalemia, elevated ACTH, and inadequate cortisol response to Cosyntropin) suggest primary adrenal insufficiency (Addison's disease). The most common cause in developed countries is autoimmune adrenalitis. Tuberculosis is less common today, and metastasis or hemorrhage would typically have additional clinical clues.

Correct Answer: A

Rationale: Burkholderia cepacia is a common pathogen in cystic fibrosis patients, causing severe lung infections.

Correct Answer: D

Rationale: Late menopause and nulliparity increase ovarian cancer risk due to prolonged ovulation. Early pregnancy (<30) reduces risk by decreasing ovulatory cycles. Oral contraceptives also reduce risk by suppressing ovulation, making it the exception.

Correct Answer: D

Rationale: Asking about food consumption can help identify potential sources of infection such as contaminated food or water.

Correct Answer: C

Rationale: Low complement levels (C3 and C4) along with significant proteinuria and hematuria indicate systemic lupus erythematosus. Lupus nephritis often presents with these laboratory abnormalities.