This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Adrenal Gland, Subject name: Pathology
A 14-year-old boy is brought to OPD with c/o increasing weakness, easy fatigability, and weight loss over the past 3 months. In addition, he has recently developed nausea, vomiting, and abdominal pain. His blood pressure is markedly decreased, and he has increased pigmentation of his skin creases. These findings are suggestive of 
Select and explain. 
A. Cushing syndrome., B. Secondary hyperaldosteronism, C. Osteitis fibrosa cystica, D. Addison disease.
D: Addison disease.
Answer: D: Addison disease. 
Explanation: - The clinical findings are suggestive of Addison disease (primary adrenocoical insufficiency). - MCC cause - Tuberculosis ; Autoimmunity - Hyperpigmentation in Addison disease results from compensatory hypothalamic production of pro-opiomelanocoin, precursor peptide of both coicotropin & melanocyte-stimulating factor