Morning report

Karen Estrella-Ramadan

Hypernatremia

Definition serum sodium concentration >145 mEq/L. It is characterized by a deficit of total body

water (TBW) relative to total body sodium levels due to either loss of free water, or infrequently, the administration of hypertonic sodium solutions

Extracellular and plasma volumes tend to be maintained in hypernatremic dehydration until dehydration is severe (ie, when the patient loses >10% of body weight).

Na140meq

Na180meq

Cerebral edema

Na180meq

Na140meq

Symptoms:-Irritability-High-pitched cry-Intermittent lethargy-Seizures-Increased muscle tone-Fever-Rhabdomyolysis]

-Oligoanuria-Excessive diuresis

Sustained hypernatremia can occur only when thirst or access to water is impaired. groups at highest risk are infants and intubated

patients. Mortality rate: 10%

In children with acute hypernatremia, mortality rates are as high as 20%.

Neurologic complications occur in 15% of patients intellectual deficits, seizure disorders, and spastic

plegias

Mechanisms:1. Hypovolemic hypernatremia

Increase water loss > than Na loss

Excessive perspiration Diarrhea Renal dysplasia Obstructive uropathy Osmotic diuresis

Mechanisms: 2. Euvolemic hypernatremia

PURE WATER DEPLETION

Central diabetes insipidus *adipsic diabetes insipidus : When ADH secretion and thirst are both impaired, affected

patients are vulnerable to recurrent episodes of hypernatremia Idiopathic causes Head trauma Suprasellar or infrasellar tumors (eg, craniopharyngioma, pinealoma) Granulomatous disease (sarcoidosis, tuberculosis, Wegener granulomatosis) Histiocytosis Sickle cell disease Cerebral hemorrhage Infection (meningitis, encephalitis) Associated cleft lip and palate Nephrogenic diabetes insipidus Congenital (familial) conditions Renal disease (obstructive uropathy, renal dysplasia, medullary cystic disease, reflux

nephropathy, polycystic disease) Systemic disease with renal involvement (sickle cell disease, sarcoidosis, amyloidosis) Drugs (amphotericin, phenytoin, lithium, aminoglycosides, methoxyflurane)

Mechanisms: 3. Hypervolemic hypernatremia

Sodium excess

Improperly mixed formula NaHCO3 administration NaCl administration Primary hyperaldosteronism

In summary….

Lab work-MUST HAVE!!! Serum: NA, osmolality, BUN, and creatinine Urine: [Na]

In hypovolemic hypernatremia: extrarenal losses: <20 mEq/L renal losses: [Na]urine >than 20 mEq/L.

In euvolemic hypernatremia, urine sodium data vary. In hypervolemic hypernatremia, the urine sodium level

is more than 20 mEq/L. Urine: Osmolarity

Uosm < Posm then the patient has either central or nephrogenic diabetes insipidus (DI)

Uosm is intermediate (between 300 to 600 mosmol/kg), the hypernatremia may be due to an osmotic diuresis or to DI

Uosm above 600 mosmol/kg, then both the secretion of and response to endogenous ADH are intact.

Imaging-should we do any? Head: should be considered in alert patients

with severe hypernatremia to rule out a hypothalamic lesion affecting the thirst center CT scans may help in diagnosing intracranial

tumors, granulomatous diseases (eg, sarcoid, tuberculosis, histiocytosis), and other intracranial pathologies

Other tests Aldosterone test Cortisol test Antidiuretic hormone (ADH) test Corticotropin (ACTH) test

Gral principles management

SODIUM correction: 0.5 mEq/h or as much as 10-12 mEq/L in 24 hours

Dehydration should be corrected over 48-72 hours.

If the serum sodium concentration is more than 200 mEq/L, peritoneal dialysis should be performed using a high-glucose, low-sodium dialysate.

Main 2 calculations

1. Maintenance fluids2. Water deficit (in L) = [(current Na level in

mEq/L ÷ 145 mEq/L) - 1] X 0.6* X weight (in kg)

*60% BW in children

40% BW in adults

Election of fluids If the patient is hypotensive: use NS, LR or 5%

albumin regardless of a high serum sodium concentration.

In hypernatremic dehydration, 0.45% NS 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.

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.

Follow-up Serum sodium levels should be monitored

every 4-6 hours 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 Record daily body weights. Restrict sodium and protein intake. Treat the underlying disease.

More about management

To be continued… on Thursday at noon : )

References http://emedicine.medscape.com/article/907653-

followup#a2651 http://

www.uptodate.com.elibrary.einstein.yu.edu/contents/etiology-and-evaluation-of-hypernatremia?source=see_link#H6017722

http://www.uptodate.com.elibrary.einstein.yu.edu/contents/treatment-of-hypernatremia?source=search_result&search=hypernatremia&selectedTitle=1%7E150

http://pediatrics.uchicago.edu/chiefs/resources/documents/HyperHypoNatremia.pdf