21/06/2025
A Case Of My Clinic
(Hypernatremia)
* scenario: 80 years male retired patient present after two week illness with lethargy and acute confusional state he recieved iv fluid (Ringer and G/W) by para medic and frequently times he is going to emergency hospital and all times they send him to home.
PMHX = is negatve and has no any chronic illness.
Ix: s.mg = 1.83, s.Na = 152, K = 4.58, cl = 122.0, iCa = 1.53 , eGFR = 6.9
Approach
1. find Cause & diagnose: so, ask for (plasma osmolariy + uNa & uOsm + RBS)
* plasma osmolarity =
2 (plasma Na + plasna BUN/2.8) + (plasma glucose /18)
A.plasma osmo. > 295 = hypertonic hyper natremia
B. pl. osm. < 295 = psudo hyperNa.
* cause:
- Na + H2O loss (low total body Na):
$ Renal losses, osmotic diuresis (mannitol, glucose, urea).
$$ Extrarenal losses= excess sweet, diarrhea.
-- H2O loss + normal total body Na:
# renal loss, DI (nephrogenic, central) serum osm > 295 mOsm/L, s.Na > 145 mEq/L, Uosm < 150mOsm/L.
# # Respiratory & Skin loss
--- Excess Na + increased total body Na:
primary hyperaldosteronism, cushing syndrome, hypertonic dialysis, hypertonic Na bicarbonate, NaCl tablet
2. Dx & Mx:
A. BUN = normal, U Na > 20 mEq/L + Uosm = hypotonic = give hypotonic saline.
Or BUN = increased + U Na < 10 mEq/L, U osm > 600 - 800 mosm/L = give hypotonic saline.
B. BUN +- normal, U Na varies, Uosm often < 100 - 150 mosm/L in central DI = Water replacement, D5W.
Or BUN = increased, U Na = varies, Uosm> 600 - 800 mOsm/L = Water replacement, D5W
C. BUN +- normal, U Na > 20 mEq/L, Uosm isotonic or hypertonic = Diuretic + H2O replacement D5W
N.B:
1.Correct hypernatremia slowly over (48 - 72 hour) ==> Lower Na no faster than (1 - 2 mEq/L/hour.
2. with endogenous Na overload = salt restriction & correction of the primiary underlying disorder. If there is excess exogenous mineralocorticoid = restrict salt & modify replacement therapy.
