eMedicine Specialties > Pediatrics: Cardiac Disease and Critical Care Medicine > Critical Care
Hypernatremia: Treatment & Medication
Updated: Nov 2, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
Medical care involves the correction of hypernatremia. In correcting hypernatremia, do not rapidly decrease the sodium level because a rapid decline in the serum sodium concentration can cause cerebral edema. The recommended rate of sodium correction is 0.5 mEq/h or as much as 10-12 mEq/L in 24 hours. Dehydration should be corrected over 48-72 hours. Guidelines for hydration management have been established.4 If the serum sodium concentration is more than 200 mEq/L, peritoneal dialysis should be performed using a high-glucose, low-sodium dialysate.
- One of the following equations may be used to calculate body water deficit:
- The equations are based on a goal of plasma sodium concentration of 145 mEq/L. In children, total body water (TBW) is 60% of their lean body weight. Therefore, TBW = 0.6 X weight. Babies are an exception to these equations and may have a TBW as much as 80% of their body weight.
- Water deficit (in L) = [(current Na level in mEq/L ÷ 145 mEq/L) - 1] X 0.6 X weight (in kg)
- Water deficit (in L) = [(current Na level in mEq/L - 145 mEq/L)/145 mEq/L)] X 0.6 X weight (in kg)
- Water deficit (in L) = [1- (145 mEq/L ÷ current Na level in mEq/L)] X 0.6 X weight (in kg)
- Example calculation: A child weighs 10 kg and has a plasma sodium concentration of 160 mEq/L. By using the first equation, water deficit (in L) = [(160 mEq/L ÷ 145 mEq/L) - 1] X 0.6 X 10 = 0.62 L.
- The equations are based on a goal of plasma sodium concentration of 145 mEq/L. In children, total body water (TBW) is 60% of their lean body weight. Therefore, TBW = 0.6 X weight. Babies are an exception to these equations and may have a TBW as much as 80% of their body weight.
- The volume of replacement fluid needed to correct the water deficit is determined by using the concentration of sodium in the replacement fluid. The replacement volume can be determined as follows:
- Replacement volume (in L) = TBW deficit X [1 ÷ 1 - (Na concentration in replacement fluid in mEq/L ÷ 154 mEq/L)]
- Example calculation: If the patient from the example calculation above has a TBW of 0.62, and if the replacement fluid contains 0.2% NaCl (Na concentration of 34 mEq/L), the replacement volume (in L) = 0.62 L X [1 ÷ 1 - (34 mEq/L ÷ 154 mEq/L)] = 0.79 L. This volume has to be replaced slowly over 48-72 hours.
- The election of intravenous fluid is based on the following:
- If the patient is hypotensive, normal saline (lactated Ringer solution, or 5% albumin solution) should be used regardless of a high serum sodium concentration.
- In hypernatremic dehydration, 0.45% or 0.2% NaCl should be used as a replacement fluid to prevent excessive delivery of free water and a too-rapid decrease in the serum sodium concentration.
- In cases of hypernatremia caused by sodium overload, sodium-free intravenous fluid (eg, 5% dextrose in water) may be used, and a loop diuretic may be added.
- The serum sodium concentration should be monitored frequently to avoid too-rapid correction of hypernatremia.
- In cases of associated hyperglycemia, 2.5% dextrose solution may be given. Insulin treatment is not recommended because the acute decrease in glucose, which lowers plasma osmolality, may precipitate cerebral edema.
- Once the child is urinating, add 40 mEq/L KCl to fluids to aid water absorption into cells.
- Calcium may be added if the patient has an associated low serum calcium level.
- Serum sodium levels should be monitored every 4 hours.
Consultations
Consultation is also recommended for patients with renal dysplasia, medullary cystic disease, reflux nephropathy, or polycystic disease.
- Critical care specialist: Patients with symptomatic hypernatremia may need to be transferred to a pediatric ICU for appropriate treatment and monitoring.
- Endocrinologist: Consult an endocrinologist for patients with primary hyperaldosteronism.
- Nephrologist: Consult a nephrologist in cases of renal failure, obstructive uropathy, and serum sodium levels of more than 180 mEq/L for possible peritoneal dialysis.
Diet
- In diabetes insipidus, a sodium-restricted and protein-restricted diet should be prescribed.
Medication
The medications described below are used in patients with diabetes insipidus who have hypernatremia.
Vasopressin and vasopressin analogs
Desmopressin is a synthetic ADH with actions mimicking vasopressin. These agents are used to treat diabetes insipidus, which deprives the kidney of its capacity to produce concentrated urine. This effect results in large volumes of dilute urine (polyuria) and excessive thirst (polydipsia). Serum sodium concentrations may be elevated, but hypernatremia is most likely to be severe when fluid is restricted.
Desmopressin acetate (DDAVP)
Structural analog of vasopressin (ADH), the endogenous posterior pituitary hormone that maintains serum osmolality in a physiologically acceptable range. Works in neurohypophysial (eg, central) diabetes insipidus. Exerts similar antidiuretic effects. Vasopressin increases resorption of water at level of renal collecting duct, reducing urinary flow and increasing urine osmolality.
Adult
PO: 0.05 mg PO bid initially; titrate to effect; usual range 0.1-0.2 mg/d divided bid/tid
Intranasal: 10-40 mcg/d divided qd/bid; titrate dose to achieve control of excessive thirst and urination; not to exceed 40 mcg/d
Note: The nasal spray pump can only deliver doses of 10 mcg (0.1 mL) or multiples of 10 mcg (0.1 mL); if doses other than this are needed, the rhinal tube delivery system is preferred
Pediatric
PO: 0.05 mg PO divided bid initially; titrate to effect
Intranasal: 3 months to 12 years: 5-30 mcg/d divided qd/bid
Note: The nasal spray pump can only deliver doses of 10 mcg (0.1 mL) or multiples of 10 mcg (0.1 mL); if doses other than this are needed, the rhinal tube delivery system is preferred
Coadministration with demeclocycline and lithium decrease effects; fludrocortisone and chlorpropamide increase effects
Documented hypersensitivity; platelet-type von Willebrand disease
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Avoid overhydration in patients to benefit from its hemostatic effects
Vasopressin (Pitressin)
Exogenous, parenteral form of ADH. Antidiuretic and increases resorption of water at renal collecting ducts.
Adult
5-10 U IM/SC bid/qid; titrate to effect
Continuous IV infusion: 0.5 mU/kg/h (ie, 0.0005 U/kg/h) IV initially; double dosage every 30 min prn, not to exceed 10 mU/kg/h IV (ie, 0.01 U/kg/h)
Pediatric
2.5–10 U IM/SC bid/qid; titrate to effect
Continuous IV infusion: Administer as in adults
Lithium, epinephrine, demeclocycline, heparin, and alcohol may decrease effects; chlorpropamide, urea, fludrocortisone, and carbamazepine may potentiate effects
Documented hypersensitivity; coronary artery disease
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Caution in cardiovascular disease, seizure disorders, nitrogen retention, asthma, or migraine; excessive doses may result in hyponatremia
Diuretics
These drugs promote the excretion of water and electrolytes by the kidneys. They are used in patients with nephrogenic diabetes insipidus.
Hydrochlorothiazide (Esidrix, HydroDIURIL)
Works by increasing excretion of sodium, chloride, and water by inhibiting sodium ion transport across renal tubular epithelium. Resulting sodium depletion reduces glomerular filtration rate, enhancing reabsorption of fluid in proximal portion of nephron, decreasing delivery of sodium to ascending limb of loop of Henle and consequently reducing capacity to dilute urine.
Adult
25-100 mg/d PO qd or intermittently
Pediatric
Infants <6 months: Up to 3 mg/kg/d PO divided bid, total range 12.5-37.5 mg/d
Children 6 months to 2 years: 1-2 mg/kg/d PO divided qd/bid, total range 12.5-37.5 mg/d
Children 2-12 years: 1-2 mg/kg/d PO divided qd/bid, not to exceed 37.5-100 mg/d
Thiazides may decrease effects of anticoagulants, antigout agents and sulfonylureas; thiazides may increase toxicity of allopurinol, anesthetics, antineoplastics, calcium salts, loop diuretics, lithium, diazoxide, digitalis, amphotericin B, and nondepolarizing muscle relaxants
Documented hypersensitivity; anuria or renal decompensation
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in renal disease, hepatic disease, gout, diabetes mellitus, and erythematosus
More on Hypernatremia |
| Overview: Hypernatremia |
| Differential Diagnoses & Workup: Hypernatremia |
 Treatment & Medication: Hypernatremia |
| Follow-up: Hypernatremia |
| Multimedia: Hypernatremia |
| References |
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References
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Further Reading
Keywords
hypernatremia, high serum sodium, pure water depletion, sodium excess, water depletion exceeding sodium depletion, total body water, TBW, Na, salt poisoning, dehydration, thirst, sodium loading, diabetes insipidus, diarrhea, gastroenteritis, dysplasia, medullary cystic, polycystic, tubulointerstitial disease, obstructive uropathy, heat stroke, rhabdomyolysis, oligoanuria, craniopharyngioma, pinealoma, sarcoid, tuberculosis, Wegener granulomatosis, histiocytosis, sickle cell disease, meningitis, encephalitis, cleft lip and palate, amyloidosis
