Thread by @NephroP

1/How can #POCUS #echofirst help in the evaluation of #hyponatremia?
#Nephrology consulted for low sodium. Pt received diuretic for shortness of breath (which was possibly due to hiatal hernia as shown on CXR).
2 physicians FELT patient was EUVOLEMIC
Small 🧵below 👇 #MedEd

2/Based on the above labs, it does look like euvolemic hyponatremia (Urine Na is high, Uosm >100 but not too high, BUN not high). BP was 150s systolic.
That's it? Give some salt tablets or UreNa etc.?
No; perform PHYSICAL EXAM (= #POCUS)
IVC was small - doesn't tell much 😬

3/ Next step? Look at the heart, assess stoke volume.
Recent echo LVEF>50%
LV contraction looks good visually
We measured LVOT VTI (couldn't measure LVOT diameter due to chest deformity precluding good PLAX view but its not a problem; VTI is generally enough)
#POCUS

4/ #POCUS 👆 shows low VTI unexpected for normal EF.
BP is fine but flow changes precede ⬇️ in BP. Cannot rely.
Patient is likely hypovolemic. Lets recommend fluids but after making sure pt is fluid responsive. So, performed passive leg raise. 👇

5/ Repeat VTI improved by >15% without significant change in HR. That means the patient is volume responsive.
I took average of at least 3 readings to account for error.
#POCUS #echofirst

6/ Next step: Recommended Normal Saline administration. Na improved to 130 in 2 days. True euvolemic hypoNa would not have improved as U osm was less than that of saline.
Repeat #POCUS performed - If VTI improves, it proves our diagnosis. Here it is 👇

7/ Average VTI ~21 (I performed 6 readings to be sure) - Normalized!
The diagnosis of hypovolemic hyponatremia is accurate!!
There could be underlying chronic hypoNa, poor protein intake etc. but that's not the primary driving force here.

8/ Take home points:
1/ Appropriate management of #hyponatremia depends on accurate assessment of volume status
2/ Conventional exam is not always reliable for fluid assessment
3/ Don't trust anybody's FEELINGS about volume. Examine (#POCUS) the patient.

9/ A slideshow of my old lecture on hyponatremia. May help if read at low speed (0.5 or 0.25x) #Nephrology #MedEd

Cc hemodynamic friends @khaycock2 @ArgaizR @ThinkingCC @KalagaraHari @khaledsidiya @RJonesSonoEM @Thind888 et al. for further discussion.