Hypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium. The total volume of water lost (usually via GI or renal routes) is regained through normal oral intake. Therefore, if a patient has access to water and an intact thirst mechanism, many etiologies of hypernatremia may remain hidden. The etiology of hypernatremia is often easily determined by clinical history. Treatment is primarily a replacement of the free water deficit by IV or oral routes.
Water regulationWater RegulationRenal Na+ and water regulation work in tandem to control how fluid is distributed throughout the compartments of the body. Sodium is the body’s dominant extracellular solute, and is responsible for the osmotic force that keeps differing amounts of water in each compartment. Changes in Na+ balance are sensed by the body through changes in blood volume. Renal Sodium and Water Regulation is controlled by the interplay between the osmoreceptorsOsmoreceptorsRenal Sodium and Water Regulation in the hypothalamusHypothalamusThe hypothalamus is a collection of various nuclei within the diencephalon in the center of the brain. The hypothalamus plays a vital role in endocrine regulation as the primary regulator of the pituitary gland, and it is the major point of integration between the central nervous and endocrine systems.Hypothalamus and the response to antidiuretic hormoneAntidiuretic hormoneAntidiuretic hormones released by the neurohypophysis of all vertebrates (structure varies with species) to regulate water balance and osmolarity. In general, vasopressin is a nonapeptide consisting of a six-amino-acid ring with a cysteine 1 to cysteine 6 disulfide bridge or an octapeptide containing a cystine. All mammals have arginine vasopressin except the pig with a lysine at position 8. Vasopressin, a vasoconstrictor, acts on the kidney collecting ducts to increase water reabsorption, increase blood volume and blood pressure.Hypernatremia (ADH) in the kidneysKidneysThe kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine.Kidneys: Anatomy, resulting in very tight control of serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia and plasma osmolalityPlasma osmolalityVolume Depletion and Dehydration.
Allows water to move from the tubular fluid into the renal medulla via diffusionDiffusionThe tendency of a gas or solute to pass from a point of higher pressure or concentration to a point of lower pressure or concentration and to distribute itself throughout the available space. Diffusion, especially facilitated diffusion, is a major mechanism of biological transport.Peritoneal Dialysis and Hemodialysis
ADH stimulates the production and insertion of aquaporin channelsChannelsThe Cell: Cell Membrane in the collecting ductCollecting ductStraight tubes commencing in the radiate part of the kidney cortex where they receive the curved ends of the distal convoluted tubules. In the medulla the collecting tubules of each pyramid converge to join a central tube (duct of bellini) which opens on the summit of the papilla.Renal Cell Carcinoma:
High ADH levels → maximal levels of water reabsorption → concentrated urine
Low ADH levels → minimal levels of water reabsorption → dilute urine
Plasma osmolality and antidiuretic hormone (ADH): graph illustrating the relationship between the plasma osmolality of ADH release
Image by Lecturio.
Etiology
Etiologies of hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia are organized according to volume statusVolume StatusACES and RUSH: Resuscitation Ultrasound Protocols.
Hypervolemic hypernatremiahypervolemic hypernatremiaHypervolemic hypernatremia is when the hypernatremia is cause by gain of more sodium than water.Hypernatremia[5,6,8,9,12,15,16]
Gain of more sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia than water
Excessive intake of sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia:
Infusion of isotonicIsotonicSolutions having the same osmotic pressure as blood serum, or another solution with which they are compared.Renal Sodium and Water Regulation saline, hypertonic salineHypertonic salineHypertonic sodium chloride solution. A solution having an osmotic pressure greater than that of physiologic salt solution (0. 9 g NaCl in 100 ml purified water).Hyponatremia, or sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.HyponatremiabicarbonateBicarbonateInorganic salts that contain the -HCO3 radical. They are an important factor in determining the ph of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.Electrolytes solutions
Oral ingestion of salt tablets (i.e., for the treatment of hyponatremiaHyponatremiaHyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism.Hyponatremia)
Salt poisoning (i.e., excessive oral ingestion of table salt)
AldosteroneAldosteroneA hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Hyperkalemia mediated:
EuvolemicEuvolemicSyndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[5,6,8,9,12–15]
Loss of water only
DiabetesDiabetesDiabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance.Diabetes Mellitus insipidus (DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus) (both central and nephrogenic)
DementiaDementiaMajor neurocognitive disorders (NCD), also known as dementia, are a group of diseases characterized by decline in a person’s memory and executive function. These disorders are progressive and persistent diseases that are the leading cause of disability among elderly people worldwide.Major Neurocognitive Disorders
Mechanically ventilated patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship
Restrained patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship
Impaired thirst mechanism (more common in the elderly)
Medications:
LithiumLithiumAn element in the alkali metals family. It has the atomic symbol li, atomic number 3, and atomic weight [6. 938; 6. 997]. Salts of lithium are used in treating bipolar disorder.Ebstein’s Anomaly
AminoglycosidesAminoglycosidesAminoglycosides are a class of antibiotics including gentamicin, tobramycin, amikacin, neomycin, plazomicin, and streptomycin. The class binds the 30S ribosomal subunit to inhibit bacterial protein synthesis. Unlike other medications with a similar mechanism of action, aminoglycosides are bactericidal. Aminoglycosides
Amphotericin
PhenytoinPhenytoinAn anticonvulsant that is used to treat a wide variety of seizures. The mechanism of therapeutic action is not clear, although several cellular actions have been described including effects on ion channels, active transport, and general membrane stabilization. Phenytoin has been proposed for several other therapeutic uses, but its use has been limited by its many adverse effects and interactions with other drugs.First-Generation Anticonvulsant Drugs
Loss of more water than sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia
GI losses:
DiarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea
VomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
MannitolMannitolA diuretic and renal diagnostic aid related to sorbitol. It has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity.Osmotic Diuretics
Elevated ureaUreaA compound formed in the liver from ammonia produced by the deamination of amino acids. It is the principal end product of protein catabolism and constitutes about one half of the total urinary solids.Urea Cycle from excessive tube feeding
Recovery from AKIAKIAcute kidney injury refers to sudden and often reversible loss of renal function, which develops over days or weeks. Azotemia refers to elevated levels of nitrogen-containing substances in the blood that accompany AKI, which include BUN and creatinine. Acute Kidney Injury
Increased insensible water loss (i.e., sweat, burnsBurnsA burn is a type of injury to the skin and deeper tissues caused by exposure to heat, electricity, chemicals, friction, or radiation. Burns are classified according to their depth as superficial (1st-degree), partial-thickness (2nd-degree), full-thickness (3rd-degree), and 4th-degree burns. Burns, feverFeverFever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever)
Can also include central and nephrogenic DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus
The primary clinical finding in hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia is thirst. If the patient is unable to ingest enough water to keep their serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia from rising significantly, dehydrationDehydrationThe condition that results from excessive loss of water from a living organism.Volume Depletion and Dehydration and neurologic findings may also occur. The severity of neurologic findings depends on the acuity and magnitude of the hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia.
Acute hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,10,16]
Onset < 48 hours
More likely to be symptomatic (due to less time for brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification adaptation)
Less severe increases in serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia are needed to induce symptoms.
Chronic hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,10,16]
Onset > 48 hours (or unknown)
Less likely to be symptomatic (due to adequate time for brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification adaptation)
More severe increases in serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia are needed before symptoms will appear.
Mild symptoms[9]
HeadacheHeadacheThe symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders.Brain Abscess
AnorexiaAnorexiaThe lack or loss of appetite accompanied by an aversion to food and the inability to eat. It is the defining characteristic of the disorder anorexia nervosa.Anorexia Nervosa
NauseaNauseaAn unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses.Antiemetics
VomitingVomitingThe forcible expulsion of the contents of the stomach through the mouth.Hypokalemia
Severe symptoms[5,9,15]
LethargyLethargyA general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction.Hyponatremia
Confusion
Neuromuscular irritability
SeizuresSeizuresA seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
ComaComaComa is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma
Diagnosis
In most cases, the etiology of hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia (Na+ > 145 mmol/L) will be clear and treatment can be initiated without any further testing.[9,10,16] If the diagnosis is not clear, the following steps may be helpful:
Quickly identify acute causes and very severe cases:[5,9,10]
Examples of acute causes: salt poisoning, DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes InsipiduspatientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship without free access to water
Example of a very severe case: Na > 160 mmol/L
If acute, urgent and aggressive treatment is warranted.
If severe but not necessarily acute, prioritize urgent treatment over definitive diagnosis.
Ongoing losses: Address any other factors to limitLimitA value (e.g., pressure or time) that should not be exceeded and which is specified by the operator to protect the lungInvasive Mechanical Ventilation further free water replacement needs.
Etiology unknown and only mild hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia:[5,9]
Primary hyperaldosteronismPrimary hyperaldosteronismAutonomous (renin-independent) secretion of aldosterone.Hyperaldosteronism diagnosis → check plasmaPlasmaThe residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.Transfusion Products levels of:
ReninReninA highly specific (leu-leu) endopeptidase that generates angiotensin I from its precursor angiotensinogen, leading to a cascade of reactions which elevate blood pressure and increase sodium retention by the kidney in the renin-angiotensin system.Renal Sodium and Water Regulation
AldosteroneAldosteroneA hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Hyperkalemia
Etiology unknown and not aldosterone-mediated:[9,10,16]
Urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation < 300 mOsm/kg (< plasma osmolalityPlasma osmolalityVolume Depletion and Dehydration): DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus
Central DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus: urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation increases after desmopressinDesmopressinHemophilia
Nephrogenic DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus: no change in urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation after desmopressinDesmopressinHemophilia
Urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation indeterminate (300–600 mOsm/kg): DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus vs. osmotic diuresisOsmotic diuresisVolume Depletion and Dehydration
Check the response to desmopressinDesmopressinHemophilia to diagnose possible DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus.
Urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation > 600 mOsm/kg (usually nonrenal water loss (i.e., diarrheaDiarrheaDiarrhea is defined as ≥ 3 watery or loose stools in a 24-hour period. There are a multitude of etiologies, which can be classified based on the underlying mechanism of disease. The duration of symptoms (acute or chronic) and characteristics of the stools (e.g., watery, bloody, steatorrheic, mucoid) can help guide further diagnostic evaluation. Diarrhea)):
Note: high urine osmolalityOsmolalityPlasma osmolality refers to the combined concentration of all solutes in the blood.Renal Sodium and Water Regulation represents the appropriate response by the kidneysKidneysThe kidneys are a pair of bean-shaped organs located retroperitoneally against the posterior wall of the abdomen on either side of the spine. As part of the urinary tract, the kidneys are responsible for blood filtration and excretion of water-soluble waste in the urine.Kidneys: Anatomy to high plasma osmolalityPlasma osmolalityVolume Depletion and Dehydration in hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia
Diagnostic algorithm for hypernatremia with an unknown etiology:[9,12]
Keep in mind that an evaluation is not necessary if the underlying cause is ascertained from the patient’s history and physical examination.
DI: diabetes insipidus; Uosm: urine osmolality
Image by Lecturio.
Management
Management may vary depending on practice location. The following information is based on US and UK literature.
General considerations
HypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia is treated by replacing the free water deficit by giving a hypotonicHypotonicSolutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Renal Sodium and Water Regulation solution (i.e., 5% dextroseDextroseIntravenous Fluids in water IV). Management is generally empirical with frequent monitoring of the serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia and adjustment of the fluid rate.
Give isotonicIsotonicSolutions having the same osmotic pressure as blood serum, or another solution with which they are compared.Renal Sodium and Water Regulation fluids.
After stabilization, switch to hypotonicHypotonicSolutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Renal Sodium and Water Regulation fluids to address hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia.
If DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus (euvolemicEuvolemicSyndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH)):[9,13,16]
Give hypotonicHypotonicSolutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Renal Sodium and Water Regulation fluids to correct hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia.
Resume or start desmopressinDesmopressinHemophilia to maintain normal serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia (for central DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus)
If hypervolemic:[13,15]
If aldosteroneAldosteroneA hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Hyperkalemia mediated:
May only need free access to oral hypotonicHypotonicSolutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Renal Sodium and Water Regulation fluids (hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia should be mild)
Treat the underlying condition.
Other causes:
Consider adding a loop diuretic with hypotonicHypotonicSolutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Renal Sodium and Water Regulation fluid administration to induce natriuresis.
Consider hemodialysisHemodialysisProcedures which temporarily or permanently remedy insufficient cleansing of body fluids by the kidneys.Crush Syndrome in end-stage renal disease or refractory cases.
Estimating sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia correction rate (based on fluids given):[10,13]
Does not account for continued fluid loss (e.g., urine, insensible)
Not entirely reliable, but can be a starting point
Table: SodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia concentration of IV fluidsIV fluidsIntravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids[9]
For all patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship, the basic treatment strategy involves the following steps:[9,13]
Calculate the free water deficit
Determine a suitable serum Na+ correction rate
Estimate ongoing free water losses (e.g., renal, gastrointestinal, insensible)
Create suitable fluid repletion program (including monitoring and adjustment)
Acute hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia:[9,10]
Uncommon (only occurs in specific situations):
Salt poisoning
DIDIDiabetes insipidus (DI) is a condition in which the kidneys are unable to concentrate urine. There are 2 subforms of di: central di (CDI) and nephrogenic di (NDI). Both conditions result in the kidneys being unable to concentrate urine, leading to polyuria, nocturia, and polydipsia.Diabetes Insipidus without appropriate compensatory water intake
Severe hyperglycemiaHyperglycemiaAbnormally high blood glucose level.Diabetes Mellitus without appropriate compensatory water intake
Identify quickly due to the need for prompt and aggressive management.
Goal:
A decrease in serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia by about 1 mmol/L/hr and a complete correction within 24 hours[5,9,14,15,16]
Note: Some literature suggests not correcting > 10 mmol/L/day.[13,15]
Determine free water deficit
Determine the total amount of free water needed for the day:
Free water deficit + insensible water losses + renal/extrarenal water losses
Febrile patientsPatientsIndividuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures.Clinician–Patient Relationship: add 3.5 mL/kg/day per 1℃
Renal free water loss = urine volume x [1 – (urine Na+ + urine K+)/serum Na+)]
Initiate D5W IV infusion:[9,10,14–16]
May be calculated (as above) → Note: Some recommend decreasing this by 75%‒50%.
May consider a starting rate of about 3‒6 mL/kg/hr[7]
Monitor serum Na+ closely and adjust the fluid rate as needed → initially monitor serum Na+ every 1‒2 hours[2,15,16]
Chronic hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia: [9,10]
Vast majority of hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia cases
Goal: Decrease serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia by about 8‒10 mmol/L/day (< 0.5 mmol/L/hr) until normal.[9,13,14,16]
Determine free water deficit
Determine the total amount of free water needed for the day
Begin D5W IV infusion:
May be calculated (as above) → Note: Some recommend decreasing this by 75%‒50%.
May consider a starting rate of 1.35 mL/kg/hr[7]
Oral free water is an option if hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia is not severe.[9,16]
Monitor serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia and adjust the rate as needed:
Check serum Na+ every 2 hours initially, then space out to 4‒6 hours.[15,16]
An acute rise in tonicityTonicityPlasma tonicity refers to the concentration of only the osmotically active solutes in bloodRenal Sodium and Water Regulation results in abrupt movement of fluid out of the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification. A slow rise in tonicityTonicityPlasma tonicity refers to the concentration of only the osmotically active solutes in bloodRenal Sodium and Water Regulation allows the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification to adapt and minimize the effect of fluid shifts. An overly rapid correction of hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia could result in abrupt movement of fluid into the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification and cause cerebral edemaCerebral edemaIncreased intracellular or extracellular fluid in brain tissue. Cytotoxic brain edema (swelling due to increased intracellular fluid) is indicative of a disturbance in cell metabolism, and is commonly associated with hypoxic or ischemic injuries. An increase in extracellular fluid may be caused by increased brain capillary permeability (vasogenic edema), an osmotic gradient, local blockages in interstitial fluid pathways, or by obstruction of CSF flow (e.g., obstructive hydrocephalus).Increased Intracranial Pressure (ICP).
Acute hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,13,15]
Sudden rise in plasmaPlasmaThe residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.Transfusion ProductstonicityTonicityPlasma tonicity refers to the concentration of only the osmotically active solutes in bloodRenal Sodium and Water Regulation → rapid shift of water out of the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification
The brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification essentially shrinks in volume.
If severe enough, the shrinking can tear the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification’s blood vessels → intracranial hemorrhageIntracranial hemorrhageSubarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most sahs originate from a saccular aneurysm in the circle of willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use.Subarachnoid Hemorrhage and death
Chronic hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,13,15]
Slower rise in plasmaPlasmaThe residual portion of blood that is left after removal of blood cells by centrifugation without prior blood coagulation.Transfusion ProductstonicityTonicityPlasma tonicity refers to the concentration of only the osmotically active solutes in bloodRenal Sodium and Water Regulation → slower shift of water out of the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification
The brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification responds with adaptive mechanisms to counter the water shift:
Takes about 48 hours: the distinction between acute (< 48 hours) and chronic (> 48 hours) hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia
Net effect is a much smaller loss of brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification volume → no tearing of vessels
Does not, however, stop other symptoms from occurring (i.e., lethargyLethargyA general state of sluggishness, listless, or uninterested, with being tired, and having difficulty concentrating and doing simple tasks. It may be related to depression or drug addiction.Hyponatremia, confusion)
OvercorrectionOvercorrectionVolume Depletion and Dehydration of acute hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,14]
Does not commonly cause clinical problems in adults
Does commonly cause clinical problems in children and young adults (i.e., < 40 years old) with severe hyperglycemiaHyperglycemiaAbnormally high blood glucose level.Diabetes Mellitus (i.e., diabetic ketoacidosisKetoacidosisA life-threatening complication of diabetes mellitus, primarily of type 1 diabetes mellitus with severe insulin deficiency and extreme hyperglycemia. It is characterized by ketosis; dehydration; and depressed consciousness leading to coma.Metabolic Acidosis)
Severe hyperglycemiaHyperglycemiaAbnormally high blood glucose level.Diabetes Mellitus results in glucoseGlucoseA primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Lactose Intolerance contributing a significant amount to hypertonicityHypertonicityVolume Depletion and Dehydration.
Plasma osmolalityPlasma osmolalityVolume Depletion and Dehydration and serum glucoseGlucoseA primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Lactose Intolerance must be monitored very closely during treatment to prevent cerebral edemaCerebral edemaIncreased intracellular or extracellular fluid in brain tissue. Cytotoxic brain edema (swelling due to increased intracellular fluid) is indicative of a disturbance in cell metabolism, and is commonly associated with hypoxic or ischemic injuries. An increase in extracellular fluid may be caused by increased brain capillary permeability (vasogenic edema), an osmotic gradient, local blockages in interstitial fluid pathways, or by obstruction of CSF flow (e.g., obstructive hydrocephalus).Increased Intracranial Pressure (ICP):
Goal: decrease in blood glucoseGlucoseA primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.Lactose Intolerance by 50–75 mg/dL/hr
OvercorrectionOvercorrectionVolume Depletion and Dehydration of chronic hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia[9,14,15,17]
Water will always shift back into the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification as hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.Hypernatremia improves.
If the water shift occurs too abruptly, cerebral edemaCerebral edemaIncreased intracellular or extracellular fluid in brain tissue. Cytotoxic brain edema (swelling due to increased intracellular fluid) is indicative of a disturbance in cell metabolism, and is commonly associated with hypoxic or ischemic injuries. An increase in extracellular fluid may be caused by increased brain capillary permeability (vasogenic edema), an osmotic gradient, local blockages in interstitial fluid pathways, or by obstruction of CSF flow (e.g., obstructive hydrocephalus).Increased Intracranial Pressure (ICP) and/or osmotic demyelinationDemyelinationMultiple Sclerosis syndrome can occur.
In practice, complications from hypernatremiaHypernatremiaHypernatremia is an elevated serum sodium concentration > 145 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled by the hypothalamus via the thirst mechanism and antidiuretic hormone (ADH) release. Hypernatremia occurs either from a lack of access to water or an excessive intake of sodium.HypernatremiaovercorrectionOvercorrectionVolume Depletion and Dehydration in adults are extremely rare:
Goal for adults: Decrease serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia by approximately 10 mEq/L/day.
Because overcorrectionOvercorrectionVolume Depletion and Dehydration is not detrimental, therapeutic reraising of serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia is not recommended if the target is exceeded.
Smaller skullSkullThe skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium.Skull: Anatomy volume → less margin for errorErrorRefers to any act of commission (doing something wrong) or omission (failing to do something right) that exposes patients to potentially hazardous situations.Disclosure of Information if the brainBrainThe part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.Nervous System: Anatomy, Structure, and Classification shrinks or swells
Much closer monitoring of treatment is needed.
Goal for children and young adults: Decrease serum sodiumSodiumA member of the alkali group of metals. It has the atomic symbol na, atomic number 11, and atomic weight 23.Hyponatremia by < 0.5 mmol/L/hr and < 10–12 mmol/L/day.
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