Hypernatremia (Practical Approach) - Dr. Gawad

Hypernatremia
Practical Approach
Mohammed Abdel Gawad
Nephrology Consultant - Alexandria - Egypt
MD Nephrology - Mansoura University
European Specialty Examination in Nephrology (ESENeph)
NephroTube Founder/Admin
Member of ISN education SoMe team
Co-chair of AFRAN Web & Media Committee
drgawad@gmail.com
@Gawad_Nephro
NephroTube Webinar, 08-July-2021

To download the lecture
contact me
drgawad@gmail.com
For more Nephrology lectures visit
www.NephroTube.com

Fluid Compartments
POTASSIUM
SODIUM
4

• Hypernatremia (serum sodium more than 145 mEq/L)
5
Hypernatremia

Hypernatremia & Hyper-osmolality
Posm = 2 (Na) + glucose mg/dl + urea
------------------------------- ----------
18 6
6

Hypernatremia & Hyper-osmolality
Posm = 2 (Na) + glucose mg/dl + urea
------------------------------- ----------
18 6
7

Neurological Symptoms
9
Brain
cells
Plasma Brain
cells
Plasma

Question 1
Is the patient’s hypernatremia related to water deficit or gain of
Na+?
Question 2
Calculate his water deficit for serum [Na+] of 140 mEq/L?
Question 3
What is your choice of fluid administration?
Question 4
Estimate the reduction in serum [Na+], if 1 L of a fluid is infused
in 1 h?

2 Steps
13
Development of Hypernatremia
In the ICU, patients are often unable to
respond to normal thirst because of
altered mentation, sedation, or intubation

UNa < 20
UNa > 20 UNa < or > 20 UNa > 20
Orthostatic changes Edema

UNa < 20
UNa > 20 UNa > 20
Blood Glucose level
UNa < or > 20

UNa < 20
UNa > 20 UNa > 20
Hypernatremia,
Hypokalemia,
Metabolic Alkalosis,
HTN
Blood Glucose level
UNa < or > 20

UNa < 20
UNa > 20 UNa > 20
Hypernatremia,
Hypokalemia,
HTN
Blood Glucose level
Polyuria
Polyuria
UNa < or > 20

Question 1
Is the patient’s hypernatremia related to water
deficit or gain of Na+?

Question 1
Is the patient’s hypernatremia related to water
deficit or gain of Na+?
The patient’s hypernatremia is due to water deficit rather
than Na+ gain, as the patient has orthostatic changes

UNa < 20
UNa > 20 UNa > 20 UNa > 20
Hypernatremia,
Hypokalemia,
HTN
Blood Glucose level
Polyuria
Polyuria

AJKD. VOLUME 72, ISSUE 5, PA17-A19, NOVEMBER 01, 2018

Am J Kidney Dis. 67(3):507-511, 2016.

Handbook of Critical Care Nephrology. Chapter 20. 2021

2016 Mar;12(3):168-76
pre-provasopressin
Copeptin is a 39-
amino acid-long
peptide derived from
the C-terminus of pre-
pro-hormone of
arginine vasopressin,
neurophysin II and
copeptin

urine osmolality ×
urine volume >900
mosmol/day
Am J Kidney Dis. 67(3):507-511, 2016.

Am J Kidney Dis. 2016 Mar;67(3):507-11

Question 2
Calculate his water deficit for serum [Na+] of 140 mEq/L?

Calculation of Water Deficit
Add obligatory water output to the calculated infustae volume
• Obligatory water output from sweat and stool, which is approximately 30 to 40 mL/h
• Ongoing urinary and/or gastrointestinal losses is roughly equivalent to losing 50 mL/h

Assess volume status
Hypovolemia
Step 1: Correction of volume deficit:
Administer isotonic saline
(only in cases of frank circulatory
compromise until hypovolemia
improves)
Step 2: Correction of water deficit:
Calculate water deficit then replace
Euvolemia
Correction of water deficit:
Calculate water deficit then
replace
Hypervolemia
Calculate water deficit then replace
Step 2: Removal of Na:
Furosemide (20-40mg/6hrs)
The ideal fluid is enteral water.
Often patients in the ICU have various contraindications
to enteral intake and in that case D5W can be used.

Assess volume status
Hypovolemia
Step 1: Correction of volume deficit:
Administer isotonic saline
(only in cases of frank circulatory
compromise until hypovolemia
improves)
1- Calculate water deficit
2- Administer 0.45% saline, 5%
dextrose, or oral water
Euvolemia
Correction of water deficit:
2- Administer 0.45% saline,
5% dextrose, or oral water
Hypervolemia
2- Administer 5% dextrose
Step 2: Removal of Na:
Furosemide (20-40mg/6hrs)
Question 3
What is your choice of fluid administration?

Treatment of Acute Hypernatremia
• Correct the serum sodium at an initial rate of 2-3 mEq/L/h (for 2-3 h)
(maximum total, 12 mEq/L/d).
Treatment of Chronic Hypernatremia
• Corrected at a rate not to exceed 0.5 mEq/L/h and a total of 8-10
mEq/d
Measure serum and urine electrolytes every 1-2 hours
Measure serum and urine electrolytes every 1-2 hours

>0.5 mmol/L per hour overall and >8, >10, and >12 mmol/L per 24 hours
chronic hypernatremia
128 with chronic
hypernatremia

Cerebral adaptation to hypernatremia
(Increase intracellular osmolality)
52
Immediate response:
increase in intracellular electrolytes.
But it is a limited because a there
is a maximum concentration that is
tolerable for cell function

Cerebral adaptation to hypernatremia
(Increase intracellular osmolality)
53
Later response:
Organic solutes (osmolytes) as Inositol,
glutamine, glutamate and taurine begin to
accumulate 24 to 48 hours after the onset
of hypernatremia

Question 4
Estimate the reduction in serum [Na+], if 1 L of a fluid
is infused in 1 h?

IMPORTANT !!!!
• It must be emphasized that the calculation of fluid deficit is only an
estimate based on several assumptions.
• When treating a patient with hypernatremia, it is important to
frequently assess plasma sodium to assure that the rate of correction
is proceeding as planned.
56

Evaluation & Follow up !!!!
• To assure an appropriate rate of correction, plasma sodium should be
measured frequently.
• Initially, plasma sodium checks should be about every two hours; less
frequent checks may occur when the plasma sodium is falling at a
predictable rate.
57

Hypernatremia (Practical Approach) - Dr. Gawad

Hypernatremia (Practical Approach) - Dr. Gawad

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