The main cause of low sodium also known as hyponatremia is drinking too much water which dilutes the sodium levels in your blood.
Drinking too much water, especially without adequate electrolyte replacement, can dilute the sodium concentration in your blood and lead to low sodium levels.
Even conditions such as kidney disease and kidney failure can impair your body's ability to regulate fluid and electrolyte balances and lead to low sodium levels.
And certain medications like water pills or diuretics and even pain medications and some antidepressants can also lead to low sodium levels.
And conditions such as the syndrome of inappropriate antidiuretic hormone secretion or adrenal insufficiency also known as Addison's disease can disrupt fluid and electrolyte balance and cause low sodium levels.
Hear failure, liver disease and even certain gastrointestinal problems such as severe vomiting or diarrhea as well as excessive sweating can cause low sodium levels and lead to hyponatremia.
Low sodium is also known as hyponatremia and is when the sodium in your blood falls below 135 mEq/L.
Normal blood sodium levels are between 135 to 145 milliequivalents per liter or mEq/L.
Symptoms of low sodium are headache, fatigue, confusion and nausea.
When you have low sodium, limited fluid intake, medications and sometimes hospitalization may be required.
The action of hormones such as atrial natriuretic peptide and vasopressin along with signals such as blood volume and reduced blood pressure are what stimulates the kidneys to release sodium and water.
When your blood volume increases, your kidneys respond by filtering more fluid and excreting more sodium and water through a process called pressure natriuresis.
And Atrial Natriuretic Peptide is released by your heart in response to high blood volume and atrial natriuretic peptide inhibits sodium and water reabsorption in your kidneys and promotes their excretion.
And ADH, also called antidiuretic hormone is released in response to low blood pressure or high blood osmolarity and promotes water reabsorption in your kidneys and conserves water.
The RAAS is also a complex system which regulates your blood pressure and your fluid volume.
And when your blood pressure drops, your kidneys release renin, which triggers the production of angiotensin II which in turn stimulates the release of aldosterone.
Aldosterone is what promotes sodium reabsorption in your kidneys and leads to water retention and also increased blood volume.
Low levels of antidiuretic hormone decreases water reabsorption in the kidneys which decrease the permeability of the cells of the collecting duct so that large quantities of dilute urine are excreted.
And an antidiuretic hormome arginine vasopressin is secreted from your posterior pituitary gland, under the influence of the hypothalamus.
To increase water retention in the kidneys vasopressin also known as ADH or antidiuretic hormone is released.
The antidiuretic hormone signals the kidneys to reabsorb more water and decreases urine output and also increasing the water levels in your body.
ADH or antidiuretic hormones are produced in the hypothalamus and is stored in the posterior pituitary gland and acts primarily on your kidneys to increase water reabsorption.
The ADH triggers the insertion of water channels called aquaporins into the collecting duct cells of your kidneys and allows water to move out of your urine and back into your bloodstream.
Other hormones are also involved which include the renin-angiotensin, aldosterone system, which plays a role in water and sodium balance, with aldosterone, which is another hormone, promoting sodium retention, which leads to water retention indirectly.
The release of ADH is triggered by factors such as increased blood osmolarity, concentrations of solutes in the blood, low blood pressure and decreased blood volume.
And in some cases your body may produce too much ADH which leads to excessive water retention and hyponatremia which is low sodium levels in your blood and is a condition called SIADH.
The urine sodium level in SIADH is often greater than 40 mEq/L or 40 mmol/L as a result of the body retaining water and diluting the sodium levels in your blood.
Normal urine sodium levels are often between 40 to 220 mEq/day or 40 to 220 mmol/day.
In SIADH the kidneys inappropriately retain water which leads to dilution of the sodium levels in your blood which is called hyponatremia and also causes a decrease in urine output.
And in some cases of SIADH, the increase in water in your body signals the kidneys to release an increased amount of salt in your urine.
The organ that SIADH affects is the kidneys which causes the kidneys to retain excess water and causes hyponatremia which is low sodium levels in your blood.
The way you fix sodium in SIADH is through fluid restriction and in some cases medications which increase water excretion or block the effects of vasopressin.
A salt solution given through an IV in the hospital is sometimes used for fixing sodium levels in SIADH.
With SIADH you don't restrict sodium but instead you restrict fluid and in some cases a high sodium diet may be considered in chronic situations to help manage the hyponatremia in SIADH.
Fluid restriction is the first line treatment for SIADH, which aims to prevent further dilution of sodium levels.
And the specific amount of fluid restriction will also vary depending on the individuals urine output, symptoms and severity of hyponatremia.
A common starting point when restricting fluid intake for SIADH is less than the urine output or a target of 800-1200 mL per 24 hours.
Restricting fluid intake is the most common treatment for SIADH as the condition of SIADH involves your body retaining too much water.
Medications such as loop diuretics are also sometimes used to help the kidneys excrete excess water and sodium although they are also often used in conjunction with fluid restriction.
And vasopressin receptor antagonists such as vaptans are medications which block the action of ADH or antidiuretic hormone and allows your kidneys to excrete more water.
And an antibiotic called demeclocycline can also be used to reduce the effects of ADH.
A hypertonic saline may also be used in severe cases of hyponatremia when associated with SIADH and is given through an IV which is a concentrated salt solution that can be used to rapidly raise your sodium levels but it has to be done under close medical solution.
And Urea which is a solute that must be excreted by your kidneys can be used to increase your osmotic load and increase urine volume which can help with free water excretion.
The drug of choice for SIADH is vasopressin receptor antagonists or vaptans such as conivaptan and tolvaptan, which are used along with fluid restriction and in severe enough cases hypertonic saline.
The reason why you should not give normal saline in SIADH is because it can worsen hyponatremia which is low sodium levels by causing water retention and diluting of the blood as the persons kidneys are already retaining water as a result of excessive ADH.
In SIADH, your body retains water as a result of the inappropriate release of antidiuretic hormone ADH which leads to hyponatremia.
Giving normal saline in SIADH will lower the serum sodium even more.
The most serious complication of SIADH is hyponatremia which causes your body to retain too much water and leads to a dilution of sodium in your blood.
Other serious complications that can occur from SIADH are brain swelling and brain damage that can lead to seizures, confusions, hallucinations, coma and even death if your sodium levels drop too rapidly.
And other complications such as respiratory failure and brain herniation can occur with SIADH although they are less common.