Normal serum sodium value

Serum sodium is a substance that plays important roles in the human body. Serum sodium has a certain normal value, and whether it is too much or too little, it indicates that the human body has certain health problems. For example, if serum sodium is low, a person may have diarrhea, high blood sugar, high blood lipids, renal insufficiency and other problems. If the serum sodium is too high, it means that the person has kidney disease, dehydration, brain damage or endocrine disease.

1. Normal value of serum sodium:

Enzymatic analysis: 136~146mmol/L (136~146mEq/L);

Ion selective electrode method: 135~145mmol/L (145~155mEq/L).

2. Decreased serum sodium

1. Loss of sodium, such as loss from the gastrointestinal tract (vomiting, diarrhea, intestinal fistula, etc.).

2. Hyperglycemia, such as diabetes, increases plasma osmotic pressure due to high sugar concentration, causing water in the cells to move outside the cells, diluting the plasma and reducing the sodium content.

3. High temperature and profuse sweating can cause sodium loss, but serum sodium is often within the normal range, which is related to the simultaneous loss of water and concentration of extracellular fluid.

4. Hyperlipidemia: Due to the high lipid content in the serum, the sodium concentration decreases, and the serum water is occupied by a large number of hydrophobic molecules. In fact, the overall sodium does not decrease.

5. Acute and severe infections may cause hyponatremia, which may be caused by incomplete regulation of gas, fluid and electrolytes. Chronic infections, such as tuberculosis, may also cause hyponatremia, which may be due to cellular metabolic disorders, Na+ entering the cells and causing mild hyponatremia.

6. Chronic renal insufficiency, such as uremia, may cause hyponatremia. Due to the increase in urea concentration in the blood, in order to maintain plasma osmotic pressure, water moves from the tissues to the blood, and the sodium is diluted and reduced. On the other hand, the sodium retention ability of the kidneys of patients with renal insufficiency is weakened, and the sodium homeostasis mechanism becomes fragile. Patients with chronic renal insufficiency often have increased plasma atrial natriuretic peptide, which may be related to the occurrence of hyponatremia because atrial natriuretic peptide has a favorable effect on sodium. Salt-losing nephritis (also known as renal salt-losing syndrome) is caused by renal tubular lesions, which reduce the response of renal tubular epithelial cells to aldosterone and lead to large-scale excretion of sodium, resulting in decreased serum sodium.

7. Endocrine diseases, such as chronic adrenocortical insufficiency, due to insufficient secretion of adrenal cortical hormones, weaken the kidney's sodium retention function, and water and sodium are lost from the kidneys.

8. Cirrhosis often causes hyponatremia, which may be related to repeated paracentesis or frequent use of diuretics. Patients with cirrhosis often have elevated plasma atrial natriuretic peptide levels, which may be another factor causing decreased serum sodium.

9. Brain diseases such as encephalitis, brain abscess, meningitis, brain trauma, cerebral hemorrhage, etc. may also cause a decrease in serum sodium levels, which may involve a series of neurohumoral factors.

10. Cardiovascular diseases, such as congestive heart failure and acute myocardial infarction, can also cause hyponatremia.

3. Increased serum sodium

1. Decreased body fluid volume, such as dehydration.

2. Kidney diseases, such as acute and chronic glomerulonephritis, are accompanied by sodium and water retention. However, due to the simultaneous water retention, clinical testing of serum sodium may show no significant changes.

3. Endocrine diseases, such as primary or secondary aldosteronism with hypernatremia; Cushing's syndrome may have mild elevation of serum sodium, or long-term use of adrenal cortical hormones may cause hyperabsorption of sodium in the renal tubules, leading to high serum sodium.

4. Brain injury can cause hypernatremia. Due to the disorder of the osmotic pressure regulation center, it becomes traumatic diabetes insipidus. The urine cannot be concentrated, fluid is lost, serum sodium increases, plasma osmotic pressure increases, and hypoosmolar urine occurs. In this case, it is difficult to normalize serum sodium even with large amounts of water.