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The electrolyte disturbance hyponatremia (British hyponatraemia) exists in humans when the sodium (Natrium in Latin) concentration in the plasma falls below 135 mmol/L. Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The International Statistical Classification of Diseases and Related Health Problems 10th Revision ( ICD -10) is a coding of diseases and signs symptoms abnormal findings E00-E35 - Endocrine diseases (E00-E07 Thyroid gland / Thyroid hormone ( Congenital iodine-deficiency syndrome ( The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify Diseases The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. Electrolytes play a vital role in maintaining Homeostasis within the body Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Blood plasma is the Liquid component of Blood, in which the Blood cells are suspended At lower levels water intoxication may result, an urgently dangerous condition. Water intoxication (also known as hyperhydration or water poisoning) is a potentially fatal disturbance in Brain functions that results when the Hyponatremia is an abnormality that can occur in isolation or, as most often is the case, as a complication of other medical illnesses. In the case of other mammals, particularly agricultural animals, different indications are relevant. The following refers to humans; an introduction to sodium deficiency in cattle is appended.
Most patients with chronic water intoxication are asymptomatic, but may have symptoms related to the underlying cause. A symptom' (from Greek σύμπτωμα, "accident misfortune that which befalls" from συμπίπτω, "I befall" from
Severe hyponatremia may cause osmotic shift of water from the plasma into the brain cells. Osmosis is the Diffusion of a solvent (frequently water through a semi-permeable membrane, from a solution of low solute concentration (high water potential The brain is the center of the Nervous system in animals All Vertebrates and the majority of Invertebrates have a brain The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called Typical symptoms include nausea, vomiting, headache and malaise. Nausea ( Latin: Nausea, Greek:, " Sea-sickness " also called wamble) is the sensation of unease and discomfort Vomiting (also called throwing up, emesis) is the forceful expulsion of the contents of one's Stomach through the Mouth and sometimes the A headache ( cephalalgia in medical terminology is a condition of pain in the Head; sometimes Neck or upper back pain may also be interpreted Malaise is a feeling of general discomfort or uneasiness an "out of sorts" feeling often the first indication of an infection or other disease As the hyponatremia worsens, confusion, diminished reflexes, convulsions, stupor or coma may occur. A reflex action, also known as a reflex, is an involuntary and almost instant movement in response to stimulus. An epileptic seizure is caused by excessive and/or hypersynchronous electrical Neuronal activity and is usually self-limiting Stupor is the lack of critical cognitive function and Level of consciousness wherein a sufferer is almost entirely unresponsive and only responds to base stimuli such as pain In Medicine, a coma (from the Greek koma, meaning deep sleep is a profound state of Unconsciousness. Since nausea is, itself, a stimulus for the release of ADH, which promotes the retention of water, a positive feedback loop may be created and the potential for a vicious circle of hyponatremia and its symptoms exists. Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Positive feedback, sometimes referred to as "cumulative causation" is a Feedback loop system in which the system responds to perturbation in the same direction
An abnormally low plasma sodium level is best considered in conjunction with the person's plasma osmolarity and extracellular fluid volume status. Osmolarity is a measure of the osmoles of solute per Liter of solution while the osmolality is a measure of the osmoles of Solute per Kilogram Extracellular fluid (ECF usually denotes all body fluid outside of cells
Most cases of hyponatremia are associated with reduced plasma osmolarity. Plasma osmolality is a measure of the concentration of substances such as Sodium, Chloride, Potassium, Urea, Glucose, and other In fact, the vast majority of adult cases are due to increased vasopressin, i. Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in e. , anti-diuretic hormone (ADH). Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Vasopressin is a hormone that causes retention of water; salt is also retained but to a lesser extent. Hence, the patient with hyponatremia can be viewed as the patient with increased ADH activity. It is the physician's task to identify the cause of the increased ADH activity in each case.
In patients who are volume depleted, i. e. , their blood volume is too low, ADH secretion is increased, since volume depletion is a potent stimulus for ADH secretion. As a result, the kidneys of such patients recover water and produce a fairly concentrated urine. Treatment is simple (if not without risk) — simply restore the patient's blood volume, thereby turning off the stimulus for ongoing ADH release and water retention.
Some patients with hyponatremia have normal blood volume. In those patients, the increased ADH activity and subsequent water retention may be due to "physiologic" causes of ADH release such as pain or nausea. Alternatively, they may have the Syndrome of Inappropriate ADH (SIADH). The syndrome of inappropriate antidiuretic hormone (SIADH is a condition commonly found in the hospital population especially in patients being hospitalized for Central nervous system SIADH represents the sustained, non-physiologic release of ADH and most often occurs as a side effect of certain medicines, lung problems such as pneumonia or abscess, brain disease, or certain cancers (most often small cell lung carcinoma).
A third group of patients with hyponatremia are often said to be "hypervolemic". They are identified by the presence of peripheral edema. In fact, the term "hypervolemic" is misleading since their blood volume is actually low. The edema underscores the fact that fluid has left the circulation, i. e. , the edema represents fluid that has exited the circulation and settled in dependent areas. Since such patients do, in fact, have reduced blood volume, and since reduced blood volume is a potent stimulus for ADH release, it is easy to see why they have retained water and become hyponatremic. Treatment of these patients involves treating the underlying disease that caused the fluid to leak out of the circulation in the first place. In many cases, this is easier said than done when one recognizes that the responsible underlying conditions are diseases such as liver cirrhosis or heart failure — conditions that are notoriously difficult to manage, let alone cure.
It is worth considering separately, the hyponatremia that occurs in the setting of diuretic use. Patients taking diuretic medications such as furosemide (Lasix), hydrochlorothiazide, chlorthalidone, etc. Furosemide ( INN) or frusemide (former BAN) is a Loop diuretic used in the treatment of congestive Heart failure and Edema Hydrochlorothiazide, sometimes abbreviated HCT, HCTZ, or HZT is a popular Diuretic drug of the Thiazide class that acts by inhibiting Chlortalidone (formerly spelled chlorthalidone in the UK and still so called in the United States is a drug used to treat hypertension , become volume depleted. That is to say that their diuretic medicine, by design, has caused their kidneys to produce more urine than they would otherwise make. This extra urine represents blood volume that is no longer there, that has been lost from the body. As a result, their blood volume is reduced. As mentioned above, lack of adequate blood volume is a potent stimulus for ADH secretion and thence water retention.
Hyponatremia can also result from adrenal insufficiency, congenital adrenal hyperplasia, hypothyroidism, and some medications. Adrenal insufficiency is a condition in which the Adrenal glands located above the Kidneys do not produce adequate amounts of steroid hormones (chemicals produced by the Congenital adrenal hyperplasia ( CAH) refers to any of several Autosomal Recessive Diseases resulting from Mutations Hypothyroidism is the disease state in humans and animals caused by insufficient production of Thyroid hormone by the Thyroid gland. However, the vast majority of cases, and perhaps all, of medication-associated hyponatremia is not due to the medication per se. Rather, the medication has caused SIADH or has led to volume depletion (see above)
A recent surge in death from hyponatremia has been attributed to overintake of water while under the influence of MDMA. MDMA ( 34-methylenedioxy- N -methylamphetamine) most commonly known today by the street name Ecstasy (often abbreviated E, X, This may also be related to inappropriate release of ADH that is stimulated by the drug.
Also, Almond et al.  found hyponatremia in as many as 13% of runners in a recent Boston Marathon, with life-threatening hyponatremia (serum Na below 120 mmol/L) in 0. 6%. The runners at greatest risk of serious water intoxication had moderate weight gain during the race due to excessive water consumption (see reference). Water intoxication (also known as hyperhydration or water poisoning) is a potentially fatal disturbance in Brain functions that results when the Siegel et al.  recently found that in addition to over-zealous drinking, the cause of exercise-associated hyponatremia (EAH) is from an inappropriate secretion of the hormone arginine vasopressin, or antidiuretic hormone. This excess hormone secretion prevents the kidneys from excreting the excess water in the urine.
Certain conditions that interfere with laboratory tests of serum sodium concentration (such as extraordinarily high blood levels of lipid or protein) may lead to an erroneously low measurement of sodium. Lipids are broadly defined as any fat- Soluble ( lipophilic) naturally-occurring Molecule, such as fats oils waxes cholesterol sterols fat-soluble Proteins are large Organic compounds made of Amino acids arranged in a linear chain and joined together by Peptide bonds between the Carboxyl This is called pseudohyponatremia, and can occur when laboratories use the flame-photometric and indirect (but not direct) ion-selective electrode assays.  This is distinct from a true dilutional hyponatremia that can be caused by an osmotic shift of water from cells to the bloodstream after large infusions on mannitol or intravenous immunoglobulin. Mannitol or hexan-123456-hexol (C6H8(OH6 is a Polyol that is used as an osmotic Diuretic agent and a Intravenous immunoglobulin (IVIG is a blood product administered Intravenously It contains the pooled IgG Immunoglobulins ( Antibodies
When the plasma osmolarity is low, the extracellular fluid volume status may be in one of three states:
Treat underlying cause and give IV isotonic saline. A burn is a type of Injury that may be caused by Heat, cold, Electricity, Chemicals, Light, Radiation, or Vomiting (also called throwing up, emesis) is the forceful expulsion of the contents of one's Stomach through the Mouth and sometimes the In Medicine, diarrhea, also spelled diarrhoea (see spelling differences) is frequent loose or liquid Bowel movements Acute diarrhea Urine is a liquid waste product of the body secreted by the Kidneys by a process of filtration from Blood and Excreted through the Urethra. A diuretic is any Drug that elevates the rate of urination ( Diuresis) Thiazide is a term used to describe a type of molecule and a class of Diuretic. Addison's disease (also known as chronic Adrenal insufficiency, '''hypocortisolism''' or '''hypocorticism) is a rare Endocrine disorder Cerebral salt-wasting syndrome ( CSWS) is a disease featuring Hyponatremia (low blood Sodium levels and Dehydration in response to disease processes The kidneys are complicated organs that have numerous biological roles It is important to note that sudden restoration of blood volume to normal will turn off the stimulus for continued ADH secretion. Hence, a prompt water diuresis will occur. This can cause a sudden and dramatic increase the serum sodium concentration and place the patient at risk for so-called "central pontine myelinolysis" (CPM). Central pontine myelinolysis is a neurologic disease caused by severe damage of the Myelin sheath of nerve cells in the Brainstem, more precisely in That disorder is characterized by major neurologic damage, often of a permanent nature.
Because of the risk of CPM, patients with low volume hyponatremia may eventually require water infusion as well as volume replacement. Doing so lessens the chance of a too rapid increase of the serum sodium level as blood volume rises and ADH levels fall.
The cornerstone of therapy for SIADH is reduction of water intake. The syndrome of inappropriate antidiuretic hormone (SIADH is a condition commonly found in the hospital population especially in patients being hospitalized for Central nervous system Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Polydipsia is a medical symptom in which the patient drinks abnormally large amounts of Fluids The word derives from the Greek πολυδιψία, the If hyponatremia persists, then demeclocycline (an antibiotic with the side effect of inhibiting ADH) can be used. Demeclocycline (marketed as Declomycin, Declostatin and Ledermycin) is a member of the Tetracycline antibiotics group used in various types of SIADH can also be treated with specific antagonists of the ADH receptors, such as conivaptan or tolvaptan. Arginine vasopressin ( AVP) also known as vasopressin, argipressin or antidiuretic hormone ( ADH) is a Hormone found in Conivaptan (YM 087 brand name Vaprisol) is a non-peptide inhibitor of Antidiuretic hormone (vasopressin Tolvaptan ( INN) also known as OPC-41061, is a selective competitive Arginine vasopressin receptor 2 antagonist under investigation
Placing the patient on water restriction can also help in these cases. Heart failure is a Cardiac condition that occurs when a problem with the structure or function of the Heart impairs its ability to supply Hypothyroidism is the disease state in humans and animals caused by insufficient production of Thyroid hormone by the Thyroid gland. Adrenal insufficiency is a condition in which the Adrenal glands located above the Kidneys do not produce adequate amounts of steroid hormones (chemicals produced by the The liver is a vital organ in the human body and is present in Vertebrates and some other animals Cirrhosis is a consequence of chronic Liver Disease characterized by replacement of liver tissue by fibrous Scar tissue as well as regenerative Not to be confused with Nephritic syndrome Nephrotic syndrome is a nonspecific disorder in which the Kidneys are damaged to leak large Psychogenic polydipsia is a special form of Polydipsia, caused by mental disorders
Severe hyponatremia may result from a few hours of heavy exercise in high temperature conditions, such as hiking in desert areas, or from endurance athletic events when electrolytes are not supplied. (Such an incident notably happened to long-distance athlete Craig Barrett in 1998). This article contains some information from the New Zealand Olympic Committee Year 1998 ( MCMXCVIII) was a Common year starting on Thursday (link will display full 1998 Gregorian calendar)
Sodium deficiency exists in grazing animals where soil sodium levels have been depleted by leaching. This is more common in mountainous regions. Agricultural science research conducted in the northern Thai highlands in the 1970s found that an endemic sodium deficiency masked all other nutrient deficiencies across all seasons and reduced productivity. Agricultural science is a broad multidisciplinary field that encompasses the parts of exact natural economic and Social sciences that are used in the practice and understanding The Thai Highlands are mountains in the north of Thailand that extend through Laos, Burma and China to link to the Himalayas, of which Sodium supplementation increased liveweight gain by around 30% and also reproductive rates by around 30%. Simple salt supplementation is now recommended in this region and neighbouring mountains, as both a herd management tool and for increased productivity (see sources below).