This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
[{'content': 'SIADH feature \nSelect and explain. \nA. Hyponatremia with sodium excretion > 20 mEq/L, B. Hypernatremia with hypokalemia, C. Hypernatremia with Na+ excretion < 20 mEq/L, D. Hyponatremia with hyperkalemia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: (A) Hyponatremia with sodium excretion > 20mEq/l # Syndrome of Inappropriate Antidiuretic Hormone (ADH) secretion (SIADH) is defined by the hyponatremia and hypo-osmolality resulting from inappropriate, continued secretion or action of the hormone despite normal or increased plasma volume, which results in impaired water excretion.> Diagnosis:> In the absence of a single laboratory test to confirm the diagnosis, SIADH is best defined by the classic Bartter-Schwartz criteria, which can be summarized as follows: Hyponatremia with corresponding hypo-osmolality Continued renal excretion of sodium Urine less than maximally dilute Absence of clinical evidence of volume depletion Absence of other causes of hyponatremia Correction of hyponatremia by fluid restriction> Cardinal features of SIADH include: Hyponatermia (dilutional hyponetremia with Na+ < 135 mmol/l) Decreased plasma osmolality (<280 m osm/kg) with inappropriately increased urine osmolality > 150 m osm). Urine sodium over 20 meq/l Low Blood urea Nitrogen < Wmg/L Hypouricemia (<4mg/dL), Absence of cardiac, liver or renal disease, Normal thyroid and adrenal function> A high BUN suggests a volume contracted state and excludes a diagnosis of SIADH.', 'role': 'assistant'}]