This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fluids and Electrolyte Imbalance, Subject name: Medicine
Acute hyponatremia become symptomatic at: 
Select and explain. 
A. <135 mEq, B. <125 mEq, C. <120 mEq, D. <110 meq
B: <125 mEq
Answer: B: <125 mEq 
Explanation: Hyponatremia is commonly defined as a serum sodium <135 mmol/L (<135 mEq/L). In patient with hyponatremia that develops over hours, life-threatening seizures and cerebral edema may occur at values as high as 125 mmol/L. In contrast some patients with more chronic hyponatremia that has slowly developed over months to years may be asymptomatic even with serum levels <110 mmol