The human body is mostly water, with the majority of it inside of the cells and a large portion outside of cells as well. The water contains charged minerals called electrolytes, such as sodium, which has a positive charge in water and a relatively high concentration outside of cells compared with inside cells. It has two primary roles in the body: to help cells transfer electrical and chemical currents, such as during nerve conduction and muscle contraction, and to define the distribution of water. High sodium levels, called hypernatremia, can accompany varied amounts of water in the body. High sodium with water retention has specific causes. It is important to consult a physician for the management of high sodium levels and other disorders.
Causes
High sodium with water retention is called hypervolemic hypernatremia. Water tends to attract sodium in part because of their electrical-magnetic charges. Water is a polar molecule, meaning that even though it does not have a charge, it does have a positive pole and a negative pole. The positive charge of sodium attracts water around it, so that high concentrations of sodium tend to attract more water. In this way, sodium retention can cause increased water retention. High sodium and water can be caused by the administration of intravenous fluids with a high sodium concentration, the ingestion of sea water, or by excessive adrenal gland activity in which too much of the hormones aldosterone or cortisol are made.
Symptoms
It is possible to have no symptoms from mildly high sodium levels, but the retention of water tends to be noticeable. Symptoms can include swelling of the tissues, particularly the legs in a standing position. Excess fluid in the lungs can cause shortness of breath, and high fluid levels in blood vessels can increase blood pressure. High sodium and water can interfere with nerve and muscle functioning, leading to confusion, irritability, weakness and fatigue. Very high sodium can lead to coma or death.
Diagnosis
The diagnosis of hypervolemic hypernatremia begins with a history and physical exam. For example, a history of adrenal gland problems in the family increases the chance that a person might have adrenal hyperactivity. A physical exam can reveal swelling in the feet, ankles, legs or other parts of the body. The lung sounds might be coarse from fluid in the lungs, and the breathing rate or heartbeat can be elevated or normal, while the blood pressure might be elevated. Blood tests measure the concentration of sodium and other chemicals in the blood, and urine tests can help shape the diagnosis as well.
Treatment
The treatment of high sodium and water retention generally comes in two stages. First, medications such as diuretics can be given to rid the body of water and sodium. Diuretics increase water and electrolyte loss by signaling the kidneys to make urine. After initial management, the underlying causes are addressed. If a medication is to blame or if excess intravenous fluids are the culprit, the type of medication or rate IV fluid can be changed. An adrenal gland tumor might be detected and could be removed.
References
- "Physiology (fourth edition)"; Linda Costanzo; 2008
- "Harrison's Principles of Internal Medicine (17th edition)"; Anthony Fauci et al; 2008
- "Robbins and Cotran Pathologic Basis of Disease (eight edition)"; Vinay Kumar et al; 2009
