Hypernatremia and Hyponatremia
Sodium (Na+ )
Sodium is a type of metal that is very reactive. Since it’s so reactive, sodium is never found in free form in nature. Instead, sodium is always found as a salt. The most common dietary form of sodium is sodium chloride. Sodium chloride is commonly referred to as table salt.
- It is the most abundant caution of the extra cellular fluid
- After trauma and surgery, there is a period of shut down of sodium excretion for up to 48 hours. During this period, it may not be advisable to administer large quantities of isotonic saline.
- The concentration of serum sodium is not related to the volume status of extracellular fluid. A severe volume deficit may exist with a normal low or high serum level.
- Daily requirement of sodium is one millimol/kg. The excretion of sodium by the kidneys is under the control of aldosterone.
Sodium depletion (Hyponatremia) Na+ less than 130 milliequivalent/liter
Hyponatremia (low blood sodium) is a condition that means you don’t have enough sodium in your blood. You need some sodium in your bloodstream to control how much water is in and around the cells in your body. It can present with signs and symptoms of either fluid excess or fluid overload depending on the primary cause. Hyponatremia can be associated with
- Volume depletion, sodium and water depletion. Most frequent cause of sodium and water depletion in surgery is small intestinal obstruction. Duodenal, Biliary, pancreatic and high intestinal fistula are also causes of hyponatremia.
- Water intoxication with excess volume and edema, over-prescribing of intravenous 5% D/W and colorectal washouts with plain water
Hyponatremia signs and symptoms may include:
- Nausea and vomiting
- Loss of energy, drowsiness and fatigue
- Restlessness and irritability
- Muscle weakness, spasms or cramps
- Ringer’s Lactate or Normal Saline: In cases of volume depletion.
- Fluid restriction and sodium sparing diuretics: In case of fluid excess.
Sodium Excess (Hypernatremia) Na+ more than 145 mmol/L
Hypernatremia is the medical term used to describe having too much sodium in the blood. Sodium is an important nutrient for proper functioning of the body. Most of the body’s sodium is found in the blood. It’s also a necessary part of the body’s lymph fluids and cells. Depending on the cause it can be of fluid excess or fluid deficit.
In many cases, hypernatremia is mild and doesn’t cause serious problems. However, in order to prevent or reverse problems caused by hypernatremia, it’s important to correct high sodium levels.
How are sodium levels controlled?
Hypernatremia can occur when there is a too much water loss or too much sodium gain in the body. The result is too little body water for the amount of total body sodium.
Changes in water intake or water loss can affect the regulation of the concentration of sodium in the blood. Changes in fluid can be caused by:
- dramatic changes in thirst
- changes in urine concentration
In healthy people, thirst and urine concentration are triggered by receptors in the brain that recognize the need for fluid or sodium correction. This normally results in increased water intake or changes in the amount of sodium passed in the urine. That can rapidly correct hypernatremia.
The main symptom of hypernatremia is excessive thirst. Other symptoms are lethargy, which is extreme fatigue and lack of energy, and possibly confusion.
Advanced cases may also cause muscle twitching or spasms. That’s because sodium is important for how muscles and nerves work. With severe elevations of sodium, seizures and coma may occur.
Severe symptoms are rare and usually found only with rapid and large rises of sodium in the blood plasma.
- Excessive water loss in burns or sweating, insensible losses through the lungs.
- Excess amount of 0.9% saline solution is given IV during the early operative period where there is some degree of retention of sodium.
Treatment: 5% D/W can be infused slowly