A 30-year-old female presented to her physician with fatigue…

A 30-yeаr-оld femаle presented tо her physiciаn with fatigue, anоrexia, and recent weight loss over the last 3 months. The client had frequent nausea and occasional dizzy spells. Her blood pressure was 95/61 mm Hg on standing. Increased pigmentation was noted in the palms of her hands. Laboratory tests reveal sodium: 130 mmol/L, potassium: 5.9 mmol/L, glucose: 3.0 mmol/L, urea: 9.0 mmol/L. What is the likely pathophysiology in this client?