This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrine System, Subject name: Physiology
Hypeonic dehydration would result from: 
Select and explain. 
A. G.I. fluid loss, B. Diabetes mellitus, C. Primary hypoadrenocoicalism, D. SIADH
B: Diabetes mellitus
Answer: B: Diabetes mellitus 
Explanation: ECF disturbance are of 2 types: Dehydration Overhydration DEHYDRATION: Isotonic dehydration Water & Na+ lost in equal propoion no shift of H2O k/o isotonicity of ECF seen in: GI fluid loss Burns Hemorrhage Hypeonic dehydration: H2O lost from ECF ECF becomes hypeonic H2O moves from ICF to ECF, and intracellular volume decreases seen in: Alcoholism Diabetes mellitus, diabetes insipidus. Hypotonic dehydration: H2O & Na+ lost but Na loss >>> H2O loss ECF becomes hypotonic, H2O moves to ICF compament causing secondary increase in ICF volume seen in: 1deg hypoaldosteronism 1deg hypoadrenocoicism OVERHYDRATION / VOLUME EXPANSION: Isotonic overhydration: k/o administration of oral / IV isotonic saline Hypeonic overhydration: Administration of oral / IV hypeonic saline Hypotonic overhydration: SIADH - excess ADH secreted in euvolemic states that result in hypervolemia