Hyponatremia causes, signs and symptoms, treatment. Hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 5 meq per l. Proper interpretation of the various laboratory tests helps to differentiate the various types of hyponatremia. If you have moderate, chronic hyponatremia due to your diet, diuretics or drinking too much water, your doctor may recommend temporarily cutting back on fluids. Clinical manifestations are primarily neurologic due to an osmotic shift of water. Renal loss of electrolytefree water due to ureainduced osmotic diuresis. Normal saline forms the mainstay of treatment for hypovolemic hyponatremia while 3% nacl and fluid restriction are important for euvolemic hyponatremia. Because total body sodium content is reflected by extracellular fluid ecf volume status, hyponatremia must be considered along with status of the ecf volume. Hyponatremia endocrine and metabolic disorders merck. This causes the body to suddenly excrete a lot of free water, thereby causing the sodium to rise.
Sodium is also needed for nerves, muscles, and other body tissues to work properly. May, 2014 hyponatremia, defined as a decrease in serum sodium below 6 mmoll, is a common occurrence in both inpatients and outpatients and can be found in up to 15% of the general hospital populations. Common causes include diuretic use, diarrhea, heart failure, liver disease, renal disease, and the syndrome of inappropriate adh secretion siadh. The causes of hypovolemic hyponatremia may be renal or nonrenal figure 2. It is very important for maintaining blood pressure. This form of autocorrection is by far the most common cause of overcorrection. Hyponatremia causes, pathophysiology, algorithm, correction. Intense and prolonged exercise that causes excessive sweating. Categorisation based on fluid status aids diagnosis of the underlying cause and helps guide treatment. Treatment of severe hyponatremia american society of nephrology. This watering down effect makes the amount of sodium seem low. Avoidance of neurologic injury requires a clear understanding of why the serum sodium na concentration falls and why it rises, how the brain responds to a changing serum na concentration, and what the goals of therapy should be. David mount, a kidney specialist and clinical chief of the renal division at brigham and womens hospital in.
Psychotropicinduced hyponatremia mdedge psychiatry. Hyponatremia is a common, multifactorial clinical condition. Treatment varies with the nature of onset acute or chronic, severity and symptoms. Severe hyponatremia can cause problems in the absence of hypoosmolality, however. If the level of sodium in the fluids outside the cells goes down, the fluids enter the cells causing the cells to swell. Mar 01, 2015 hyponatremia is a common electrolyte disorder defined as a serum sodium level of less than 5 meq per l. Diagnosis, evaluation, and treatment of hyponatremia american. The most common causes of hyponatremia are the syndrome of inappropriate antidiuresis siad, diuretic use. Normal range mild hyponatraemia moderate hyponatraemia severe hyponatraemia 5146 mmoll 5 mmoll 120129 mmoll of hyponatraemia step 1. A 4 to 6 meql increase in serum na concentration is sufficient to treat lifethreatening cerebral edema caused by. Most of the individual causes of hyponatremia are discussed in detail separately table 2, as are issues related to the diagnosis and treatment of hyponatremia algorithm 1 and algorithm 2 3,4. However, because the signs and symptoms of hyponatremia occur in many conditions, its impossible to diagnose the condition based on a physical exam alone. Identifying the cause and providing appropriate treatment can mitigate the adverse effects of hyponatremia 2.
Hyponatremic dehydration dehydration with serum sodium hyponatremia becomes pronounced, additional symptoms will become evident. Feb 03, 2020 hyponatremia happens when too much sodium leaves your body, or when more water than sodium stays in your blood. Hyponatremia, the most common electrolyte disorder encountered, is associated with increased morbidity and mortality even in its milder forms. Laboratory evaluation blood and urine s osm 237 mosml, u na mar 22, 2016 hyponatraemia represents a relative excess of water in relation to sodium and is defined as a serum sodium of lipids or proteins in which the concentration of sodium in the water phase is normal plasma osmolality. The precise mechanism is incompletely understood, but the syndrome of inappropriate antidiuretic hormone secretion is felt to play a significant role. Postoperative hyponatremia in the orthopedic patient is associated with longer hospitalizations, greater hospital costs, more frequent discharges to extendedcare facilities 1 and higher mortality 2.
Correction of serum sodium concentration should not exceed 68 meql in any 24hour period regardless of duration of hyponatremia, clinical presentation, and method of treatment. Diagnosis and treatment of hyponatremia american journal of. Resembles siadh table 1 except that in csw renal salt wasting and volume depletion is the main defect with secondary rise in adh whereas a high arginine vasopressin avp level is the primary etiologic event in patients with siadh table 2. There are several ways you may be able to prevent hyponatremia. Surveys from around the world suggest that up to a third of very low birthweight infants are hyponatraemic in the first week after birth and between 25 and 65% thereafter unpublished data.
Causes of hyponatremia true hyponatremia is regarded as a low sodium level in true hyponatremia as sodium and its accompanying anions are the major effective plasma solutes in the ecf, hyponatremia and hypoosmolality almost always coexist. Although sometimes called rare, it is actually more common than herniation from untreated acute hyponatremia. Drinking too much water or receiving too much fluid through an iv. Hyponatremia is decrease in serum sodium concentration of water relative to solute. To provide guidelines for appropriate investigations and treatment of hyponatraemia in hospitalised patients. Too much correction of chronic hyponatremia causes osmotic demyelination. He or she may also suggest adjusting your diuretic use to increase the level of sodium in your blood. Clinical practice guideline on diagnosis and treatment of. Hyponatremia represents a relative excess of water in relation to sodium. True hyponatremia is regarded as a low sodium level in the presence of hypoosmolality. Causes of hypernatremia involve a net gain of sodium or a loss of free water. Diagnosis and treatment of hyponatremia american journal. Learn why it happens, how to spot the symptoms, and how to get the right treatment. Hyponatremia is usually defined as a plasma sodium level hyponatremia results from the inability of the kidney to excrete a sufficient amount of fluid, or is due to excessive fluid intake.
The most common causes of hypervolemic hyponatremia are heart failure, cirrhosis, and kidney injury. Sodium helps to control the amount of water in your body. A common classification of hyponatremia is based on the amount of total body water that is present. The ddavp clamp may be used to avoid this pitfall next section. Hyponatremia can be the result of illnesses and medications. Clinical practice guideline on diagnosis and treatment of hyponatraemia goce spasovski, raymond vanholder1, bruno allolio2, djillali annane3, steve ball4. Treatment consists of correcting the underlying cause, sodium and fluid restriction, and.
Diagnosis and treatment of hyponatremia inside the silver fridge. There are several singlecenter series of osmotic demyelination documented by autopsy or magnetic resonance imaging mri table 1 33 38. Hyponatremia is a condition that occurs when sodium levels in the body are too low. Hyponatraemia is common in inpatients and this includes newborns in neonatal intensive care units. Hyponatremia defined as a serum sodium level causes of either asymptomatic or symptomatic hyponatremia. Hyponatremia annals in the clinic patient information. Hyponatremia, defined as a decrease in serum sodium below 6 mmoll, is a common occurrence in both inpatients and outpatients and can be found in up to 15% of the general hospital populations. To confirm low blood sodium, your doctor will order blood tests and urine tests. Hyponatremia happens when too much sodium leaves your body, or when more water than sodium stays in your blood. Hyponatremia treatment is aimed at addressing the underlying cause, if possible. Differential diagnosis and treatment of hyponatremia. A low sodium level in your blood may be caused by too much water or fluid in the body.
Cns disturbances such as hemorrhage, tumors, infections, and trauma. However, hyponatremia occasionally may develop in the course of treatment with drugs used in everyday. If you have a condition that can lead to low blood sodium. Any of the following conditions can lead to hyponatremia. Hyponatremia is defined as a decrease in the serum sodium concentration to a level below 6 mmol per liter. Hyponatremia may be euvolemic, hypovolemic or hypervolemic. Traditional options to manage hyponatremia in such patients are fraught with challenges.
Renal loss of electrolytefree water due to ureainduced osmotic diuresis has been described as causative in up to 10%. Low blood sodium can also be due to losing sodium from the body or losing both sodium and fluid from the body. Consider primary or secondary adrenal insufficiency as an underlying cause of the hypotonic hyponatraemia. When sodium levels are low, your body holds onto too much water. Renal causes include diuretic excess, renal failure, salt wasting nephropathy, aldosterone deficiency, chronic pyelonephritis, nephrocalcinosis, proximal renal tubular acidosis and ketonuria. Defining the cause of postoperative hyponatremia in the. Sodium is found mostly in the body fluids outside the cells. Most frequently it occurs when excessive water dilutes the amount of sodium in the body or when not enough total sodium is present in the body. Hypotonic dilutional hyponatremia represents an excess of. Hyponatremia in pneumonia journal of hospital medicine. Hyponatremia is an important and common clinical problem.
Hyponatremia defined as a serum sodium level hyponatremia. Rule out artefactual causes is the patient on iv fluids. Apr 12, 2019 hyponatremia and hypernatremia are primarily disorders of water metabolism, said dr. Hyponatremia occurs because of an imbalance of water and sodium. Mar 15, 2017 a defect in osmoregulation causes vasopressin to be inappropriately stimulated, leading to urinary concentration. Some patients also complain muscle cramps, seizures, and decreased consciousness.
An overview of the causes of hypotonic hyponatremia is presented in this topic. Whereas hypernatremia always denotes hypertonicity, hyponatremia can be associated with. Although the likelihood of demyelination caused by overcorrection of acute hyponatremia is low, no clinical advantage is derived from exceeding this cutoff. Hyponatremia and hypernatremia are classified based on volume. If the level of sodium in the fluids outside the cells goes down, the fluids enter the cells causing the. Sodium in the body fluid is used to maintain electrolyte balance, blood pressure and for the working of muscles and nerves.