Hypernatremia

A hypernatremia is a serum sodium concentration> 145 mEq / L. There is a lack of total body water relative to the total amount of sodium in the body ahead of this does that the water absorption is less than the water loss. One very important symptom is thirst. Other clinical manifestations arise due to the osmotic outflow of water from the Gehellen. There are signs on the part of the CNS, such as confusion, neuromuscular excitability, seizures and coma. Diagnosis requires the determination of serum sodium levels and occasionally further laboratory tests. The therapy is normally a controlled water replacement. In case of insufficient response to treatment tests (eg. As monitored thirst test or vasopressin administration) was performed to detect other causes than the reduced water absorption.

A hypernatremia is a serum sodium concentration> 145 mEq / L. There is a lack of total body water relative to the total amount of sodium in the body ahead of this does that the water absorption is less than the water loss. One very important symptom is thirst. Other clinical manifestations arise due to the osmotic outflow of water from the Gehellen. There are signs on the part of the CNS, such as confusion, neuromuscular excitability, seizures and coma. Diagnosis requires the determination of serum sodium levels and occasionally further laboratory tests. The therapy is normally a controlled water replacement. In case of insufficient response to treatment tests (eg. As monitored thirst test or vasopressin administration) was performed to detect other causes than the reduced water absorption.

(To hypernatremia in newborn neonatal hypernatremia.) A hypernatremia is a serum sodium concentration> 145 mEq / L. There is a lack of total body water relative to the total amount of sodium in the body ahead of this does that the water absorption is less than the water loss. One very important symptom is thirst. Other clinical manifestations arise due to the osmotic outflow of water from the Gehellen. There are signs on the part of the CNS, such as confusion, neuromuscular excitability, seizures and coma. Diagnosis requires the determination of serum sodium levels and occasionally further laboratory tests. The therapy is normally a controlled water replacement. In case of insufficient response to treatment tests (eg. As monitored thirst test or vasopressin administration) was performed to detect other causes than the reduced water absorption. Etiology hypernatremia can result from lack of total body water (TBW) in relation to the total amount of sodium body. Since the total body volume is determined on sodium by the volume status of the ECF, a hypernatremia must be considered together with the ECF volume: A distinction hypovolemia, a normovolaemia and Hypervolaemia. Note that the ECF volume, and the effective plasma volume are not identical. For example, a reduction of the effective plasma volume can occur together with a reduced ECF Volume (as diuretics use or hemorrhagic shock), but can also at elevated ECF Volume (z. B. in heart failure, in hypoalbuminemia or in capillary leak syndrome) occurrence. To hypernatremia include an impaired thirst or inadequate access to water, as well as factors affecting or primary causes. The severity of the underlying disease, which leads to the inability to drink to feel thirsty and the effects of cerebral Hyperosmolality are probably responsible for the high mortality in hospitalized adults with hypernatremia. There are various causes of hypernatremia (see Table: Major causes of hypernatremia). Important causes of hypernatremia Description Category Examples Hypovolaemic hypernatremia Reduced TBW and sodium with relatively larger decrease in TBW Gastrointestinal loss diarrhea vomiting loss through the skin burns Excessive sweating Renal losses Intrinsic renal disease loop diuretics osmotic diuresis (glucose, urea, mannitol) normovolaemic hypernatremia Reduced TBW with nearly normal total body sodium Extrarenal losses due to respiratory tachypnea Extrarenal losses renal through the skin Excessive sweating fever losses Zen tral diabetes insipidus Nephrogenic diabetes insipidus Other causes water shortage Primary Hypodipsie change the position of the Osmosensoren hypervolaemic hypernatremia Increased sodium with normal or elevated TBW supply hypertonic fluids hypertonic saline sodium bicarbonate Total parenteral nutrition Mineralokortikoidüberschuss Adrenal tumors that Deoxycorticost eron secrete Congenital adrenal hyperplasia (defect of the 11-hydroxylase) TBW = total body water (total body water). Hypovolemic hypernatremia hypernatremia A together with hypovolemia occurs when a sodium loss is accompanied by a relatively greater loss of water. Frequent extrarenal causes are the same ones that lead to hyponatremia and hypovolemia. In a severe fluid loss either a hypernatremia or hyponatremia can occur, depending on the quantitative ratio of the sodium and water loss to each other. Renal cause of hypernatremia and volume depletion may be a diuretic therapy. Loop diuretics inhibit sodium re in the concentrating units of the nephron and can increase the excretion of water. Osmotic diuresis can, due to the presence of hypertonic substances into the tubular lumen the distal nephron, also affect the renal concentration capacity. Glycerol, mannitol and urea occasionally also cause an osmotic diuresis, which can lead to hypernatremia. The most common cause of hypernatremia in the context of an osmotic diuresis is hyperglycemia in patients with diabetes. Because glucose does not cross the cell membrane without insulin, hyperglycemia dehydrated the ICF compartment additionally. The degree of hyperosmolality in hyperglycemia can be masked by a decrease in serum sodium. This sodium reduction resulting from the passage of water from the cells into the ECF (Verschiebungshyponaträmie) patients with kidney disease may also have a predisposition to hypernatremia when their kidneys are no longer capable of urine maximum konzentrieren.Normovolämische hypernatremia A hypernatremia with a normovolemia means a decrease of the TBW with almost normal values ??for the total body sodium and is a pure water deficit. Extrarenal causes water loss such. B. excessive sweating lead to sodium loss, and it may already occur hypernatremia before significant hypovolemia. A loss of nearly pure water insipidus and nephrogenic occurs in central diabetes insipidus diabetes. An essential hypernatremia (primary Hypodipsie) occasionally occurs in children with brain damage and in chronically ill elderly patients. It is characterized by an impairment of thirst sensation (eg., By lesions in the thirst center of the brain) characterized. An altered osmotic threshold for the release of vasopressin is another possible cause of normovolemic hypernatremia; cause some lesions both an impairment of thirst sensation and an altered osmotic threshold. The non-osmotic release of vasopressin appears intact, so that these patients usually normovolemic sind.Hypervolämische hypernatremia Very rarely occurs hypernatremia in conjunction with volume overload. In these cases, hypernatremia resulting from greatly increased sodium intake in conjunction with an only insufficient water absorption. An example is the excessive administration of hypertonic sodium bicarbonate for treatment of lactic acidosis. A hypernatremia may also caused by the administration of hypertonic saline or by an incorrectly prepared hyperalimentation werden.Hypernatriämie in the elderly The hypernatremia is common in older people, especially in postoperative patients and in patients receiving tube feedings or parenteral nutrition obtained. Other factors include the following: access to water depends on other persons from impairment of thirst sensation impairment of renal concentration capacity (by diuretics, impaired vasopressin release or age-related or disease-related Nephronverlust) impairment of angiotensin II formation (which contributes directly to the impairment of thirst sensation ) symptoms and complaints the main symptom of hypernatremia is thirst. Occurs in patients who have a hypernatremia and are conscious, no thirst on, this indicates a deterioration in the perception or the formation of sense of thirst. For patients whose communication skills or ability to walk is impaired, it can sometimes be difficult to express their thirst or to gain access to water. Patients whose ability to communicate is disturbed, press their thirst sometimes made by being restless. The main symptoms of hypernatremia result from disorders of the central nervous system as part of the brain cell shrinkage. Confusion, neuromuscular excitability, hyperreflexia, seizures or coma may result. Cerebrovascular damage with subcortical or subarachnoid hemorrhage and venous thrombosis have been reported in children who died from severe hypernatremia. In chronic hypernatremia osmotically active substances (idiogene osmoles) generated in CNS cells and enhance intracellular osmolality. Therefore, the extent of Gehirnzelldehydratation and the resulting CNS symptoms in chronic hypernatremia is not as hard as in acute hypernatremia. If the hypernatremia occurs together with a pathological total body sodium, you can also see most of the typical symptoms of a volume deficiency or volume overload. Patients with renal concentration defects are eliminated usually large amounts of hypotonic urine. If the losses are extrarenal, the cause of the loss is usually obvious (z. B. vomiting, diarrhea, excessive sweating) and the urine sodium concentration is low. Diagnostic serum sodium is diagnosed clinically and by means of the serum sodium levels. In patients who do not respond to simple rehydration or where hypernatremia despite adequate access to water again occurs, further diagnostic tests are warranted. To determine the underlying cause it requires the determination of the urine volume and osmolality, in particular after a phase of dehydration. In patients with elevated urine output a thirst attempt is occasionally used to switch between different states polyuric such. As central diabetes insipidus and to nephrogenic diabetes insipidus distinction. Treatment replacement of intravascular volume and the free water Replacement of intravascular volume and the free water is the most important goal of treatment. An oral hydrogenation is sufficient for awareness clear patients without significant GI disorder. In case of severe hypernatremia or in patients who are not able due to changes in consciousness or due to massive vomiting receive oral fluid, the i.v. given rehydration preference. Hypernatremia, which occurred in the last 24 hours should be corrected in the next 24 hours. Hypernatremia, which, however, chronically or of unknown duration should be compensated for 48 hours, and the serum osmolality should to avoid cerebral edema, are not faster than 0.5 mOsm / l / hour reduced. The amount of water (in liters) that is necessary to compensate for the existing deficit, is estimated using the following formula: TBW is specified in liters and by multiplying the body weight in kg of 0.6 in men and 0.5 in women determined; Serum sodium is expressed in mEq / l. This formula assumes a constant total body sodium. In patients with hypernatremia and a deficit in the total body sodium, the actual deficit of free water is greater than that calculated by the formula. Clinical calculator: water deficit in hypernatremia In patients with hypernatremia and an extracellular volume overload (increased total body sodium content) owned by 5% Dextroseinfusionslösung can be replaced, the deficit of free water. In addition, a loop diuretic can be given. Too rapid infusion of 5% Dextroseinfusionslösung glucosuria can produce and thus lead to elimination salt-free water and hypertonicity, especially in patients with diabetes mellitus. Other electrolytes, including serum potassium should be monitored and replaced as necessary. In patients with hypernatremia and normovolemia free water either owned by 5% strength by Dextroseinfusionslösung or 0.45% saline solution may be replaced. The treatment of central diabetes insipidus and acquired nephrogenic diabetes insipidus is discussed elsewhere. Patients with hypernatremia and hypovolemia, in particular patients with diabetes and a nichtketotischen hyperglycemic coma, may optionally 0.45% saline solution as an alternative to a combination of 0.9% saline and 5% dextrose solution to normalize the sodium and water balance become. Alternatively ECF volume and free water can be exchanged separately using the formula for estimating the deficit of free water. If a severe acidosis occurs (pH <7.10), sodium bicarbonate of the 5% dextrose or 0.45% saline solution may be added as long as the resulting solution is hypotonic. Summary hypernatremia is usually caused by limited access to water or an impaired thirst and less frequently by diabetes insipidus. Symptoms include confusion, neuromuscular excitability, hyperreflexia, seizures and coma. In patients who do not respond to simple rehydration, and in which no clear cause is present, the determination of the urine volume and osmolality, in particular after a phase of the dehydration may be required. Replace (<24 h or chronic) intravascular volume and free water orally or intravenously in an amount which is determined by how acutely (> 24 h) has developed the hypernatremia, while other serum electrolyte levels are also observed ( especially potassium and bicarbonate).

Health Life Media Team

Leave a Reply