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). Na140meqNa180meq 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 traumatrauma  Suprasellar or infrasellar tumors (eg, craniopharyngioma, pinealoma)craniopharyngioma  Granulomatous disease (sarcoidosis, tuberculosis, Wegener granulomatosis)sarcoidosistuberculosisWegener granulomatosis  Histiocytosis  Sickle cell disease  Cerebral hemorrhage  Infection (meningitis, encephalitis)  Associated cleft lip and palatecleft 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  NaHCO 3 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 mEq/L in 24 hours  Dehydration should be corrected over 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 fluids 2. 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  followup#a followup#a2651  s/etiology-and-evaluation-of- hypernatremia?source=see_link#H s/etiology-and-evaluation-of- hypernatremia?source=see_link#H  s/treatment-of- hypernatremia?source=search_result&search=hypernatre mia&selectedTitle=1%7E150 s/treatment-of- hypernatremia?source=search_result&search=hypernatre mia&selectedTitle=1%7E150  /HyperHypoNatremia.pdf /HyperHypoNatremia.pdf