1. Electrolyte imbalance
Dr. Mohammed Al-Ghonaim MBBS,FRCP(C)

2. Goals of this Tutorial SESSION OBJECTIVES LEARNING METHODS
Learn to effectively assess and manage various electrolyte abnormalities (NA, K)
Apply your knowledge to real cases!
LEARNING METHODS
Lecture/material review
Interactive case scenarios

3. Body’s fluid compartments

4. Sodium disorders: body’s fluid compartments
TBW = WEIGHT x .5 (women) or .6 (men)
TBW x 1/3 = ECF
TBW x 2/3 = ICF
ECF x 2/3 = Interstitial compartment
ECF x 1/4 = Intravascular compartment
What regulate Sodium balance?

5. Water content of the blood HIGH Water content of the blood LOW
Too much water drunk
Too much salt
or sweating
Brain produces
More ADH
Brain produces
Less ADH
Water content
of the blood normal
Low volume of water
reabsorbed by kidney
High volume of water
reabsorbed by kidney
Urine output
HIGH
Urine output
LOW
(small volume of
Concentrated urine)
(large volume of
dilute urine)

7. Sodium disorders [Na] is a measure of Na relative to water.
It tells you NOTHING about the total body sodium. Abnormalities in the Na concentration tell us that there are abnormalities in the amount of WATER in the ECF compartment.

8. Hyponateremia Plasma [Na+ <135 Approach: Calculate serum Osmolality
Osmolality = Osmoles/kg of water
2(Na+) + Glucose + BUN
Normal is
Determine volume status

9. Case Study: (1)
23 yr old male develops watery diarrhea. He comes to your ER lightheaded and orthostatic. On exam:
dry MM and tachycardia.
Neuro exam is normal and he is alert.
- Labs: Na 129, K 3, HCO3 20, BUN 4, Cr 88, Glucose 75, Urine Na 5, Urine osm 520.

10. Hyponatremia Hypotonic Hyponatremia Serum OSM Low Normal High
Marked hyperlipidemia
(lipemia, TG >35mM)
Hyperproteinemia
(Multiple myeloma)
Hyperglycemia
Mannitol
Hypotonic
Hyponatremia
*Note: all have ↑ADH
SIADH: inappropriate
Rest: appropriate
ECFv *
Low
High
Normal
CHF
Cirrhosis
Nephrosis
Hypothyroidism AI
SIADH
Reset Osmostat
Water Intoxication
1° Polydipsia
TURP post-op
Renal loss (UNa > 20)
Diuretics
Thiazide
K-sparing
ACE-I, ARB
IV RTA, Hypoaldo
Cerebral salt wasting
Extra-renal loss (UNa <10)
Bleeding
Burns
GI (N/V, diarrhea)
Pancreatitis

11. Hyponateremia
Hyponatremia with high osmolality: [Na] is low since water will flow into the ECF compartment as a result of hyperglycemia for example.
The calculated and measured osm will be elevated in that case. Na will decrease by approx 1.6 meq/dL for every 100 mg/dl increase in glucose above 100.
In the case of mannitol the measured osm will be high but the calculated osm will be low.

12. Case Study: (1) continue
Diagnosis:
First step: calculate osmolality
Low ( )
Second step: Volume status
Low ECF volume
Treatment:
Acute vs Chronic
Any neurological symptoms

14. Case study-2
72 yr old woman with DM presents to ER with polyuria and polydipsia x 5 days.
Normal physical examination.
Labs:
Na 129, K 4.2, Cl 89, HCO2 3.4, BUN 5, Cr 88, Glucose 780.
What is the osm?
Why is he hyponatremic?
What is the corrected Na?
What is the treatment

15. Case study-3
A 50 yr old male with h/o hyperlipidemia has the following labs:
Na 125, M-Osm 270, TGs 1000, total protein 85.

16. Case study-4
72 yr old male who is a heavy smoker presents with cough and hemoptysis.
His physical exam is completely normal in terms of volume status.
CXR reveals a 6 cm left sided chest mass.
Labs: Na 125, K 4.2, Cr 1.1, M OSM 270, Urine Na is 45. He takes no meds. TSH and am cortisol are normal.
What is causing the hyponatremia

17. Case Study: (5)
A 72-year-old woman presents with a 2-day history of presyncope when rising from a chair.
Over the last week she has had a bout of viral gastroenteritis with diarrhea.
She is drinking 2–3 L of water per day
Medications:
Hydrochlorothiazide, 25 mg/d, for HTN
On examination:
She had postural hypotension, JVP is low
Labs:
sodium 128 mmol/L, potassium 3.1 mmol/L, creatinine 125 mmol/L and urea nitrogen 10 mmol/L.

18. Hypernateremia Plasma [Na] >145
Caused primarily by Na+ gain, or water deficit
Etiology:
Impaired thirst
Water loss
Renal
Extra renal
Na+ gain
Trans cellular shift

19. Hypernateremia

20. Case study: (1) 76 yrs old male HTN,DM II, dementia
Admitted to ICU with septic shock, intubated
Called to see due to Na154,
Bp 125/76mmHg,
Urine out put 1.3 L/day

21. Case study: (2) 25 yrs old male presented with polyuria
Found to have Na 156
Bp 110/67 mmHg, low JVP
Urine out put=6 L/day
Urine osmolality 100
Calculate the osmolar excretion rate
6 x 100 = 600 Mosmole
Replace the fluid deficit
Dx Diabetes insipidis (central Vs nephrogenic)

22. Potassium disorders Potassium is one of the body's major ions.
98% of the body's potassium is intracellular
Total body potassium stores 50 mEq/kg (ie, approximately 3500 mEq in a 70-kg person).
potassium homeostasis:
GI absorption is complete
daily intake of 1 mEq/kg/d ( mEq)
90% of this excess is excreted through the kidneys
10% is excreted through the gut
Normal K level: – 5.0

23. Hypokalemia K < 3.5 mEq/L Clinical manifestations: Fatigue Cramps
Constipation
Weakness / Paralysis
Parasthesias
Arrhythmias

24. EKG Changes in Hypokalemia
Flattened T waves
ST depressions
Prominent U waves
Prolonged QT
Prolonged PR interval

25. Pathophysiology of hypokalemia
Deficient intake (Poor potassium intake)
Due to a shift from extracellular to intracellular
Increased excretion
Renal
Extra renal

26. Case study: (1) 35 yrs old male HTN on treatment
Found to have hypokalemia (K=2.9) referred for evaluation.
HCO3=29
Urine K (spot)= 30

27. How to asses kidney response?
Urinary excertion of K
U k < 15 mmol/l in hypokalemia
U k > 200 mmol/l in hyperkalemia
TTKG < 2 in hypokalemia
>8 in hyperkalemia

29. Approach to Hypokalemia
Step 1: Redistribution or depletion?
Redistribution causes
Insulin therapy (usually in DKA)
Beta 2 agonists (e.g. albuterol)
Metabolic alkalosis
Replacement of potassium in these settings may lead to overshoot and hyperkalemia

30. Approach to Hypokalemia
Step 1: Redistribution or depletion?
Depletion causes (common)
GI tract losses (diarrhea, vomiting)
Loop/thiazide diuretic therapy
Other medications (e.g. amphotericin B)
Osmotic diuresis (DKA)
Endocrinopathies (mineralocorticoid excess)
Salt wasting nephropathies/RTA’s
Magnesium deficiency

31. Approach to Hypokalemia
Step 2: Estimate the deficit
For every 100 mEq below normal, serum K+ usually drops by 0.3 mEq/L
Highly variable from patient to patient, however!!
For every 10 mEq below normal, serum K+ usually drops by 0.1 mEq

32. Approach to Hypokalemia
Step 3: Choose route to replace K+
In nearly all situations, ORAL replacement is PREFERRED over IV replacement
Oral is quicker
Oral is less dangerous
Increase dietary intake
Potatoes / Bananas
Choose IV therapy ONLY in patients who are NPO (for whatever reason) or who have severe depletion

33. Approach to Hypokalemia
Step 5: Choose dose/timing
Mild/moderate hypokalemia
3.0 to 3.5 mEq/L
60-80 mEq PO (or IV) QD, divided doses
Sometimes will require up to 160 mEq QD (severe diarrhea, IV diuretics)
Avoid too much PO at once
GI upset or just poor response
Usually divide as BID or TID dosing
Severe hypokalemia (< 3.0 mEq/L)
Can use combination of IV and PO
Avoid more than mEq PO in a single dose
Avoid IV infusion rates faster than 20 mEq/hour—can cause arrhythmia!!!

34. Approach to Hypokalemia
Step 6: Monitor/reassess
Severe hypokalemia, DKA patients
Reassess labs Q4-6 hours
Moderate hypokalemia, IV diuresis patients
Reassess labs BID to TID as needed
Mild hypokalemia
Reassess labs QD or less as needed

35. Summary: Hypokalemia PO almost always preferred over IV
KCl is preferred preparation
Don’t give too much too quickly
Be gentle in renal failure patients
Don’t forget to check magnesium levels in refractory patients

36. Hyperkalemia Symptoms Usually asymptomatic Muscle weakness / paralysis
EKG abnormalities
Peaked T waves
ST depression
1st degree AVB
QRS widening
“Sine wave sign”

37. Hyperkalemia
Elevated potassium level should be evaluated as to the following:
Step 1: Is it real?
Step 2: If real, why did it happen?
Step 3: Is this an emergency?
Step 4: Emergency Rx

38. Pathophysiology of Hyperkalemia
Increase dietary intake
shift of K from ICF to ECF such as:
acidosis
beta blocker
insulin deficiency
periodic paralysis
Decrease renal excretion :

39. EKG changes in Hyperkalemia

40. Approach to Hyperkalemia
Step 1: Is it real?
Assess for/exclude pseudohyperkalemia
Hemolysis—ask the nurse/phlebotomist/lab tech
If suspected—order STAT repeat K+ level
Potassium infusion—ask the nurse
If suspected—order STAT repeat K+ level from peripheral vein AWAY from infusion site
Check CBC (WBC > 70,000, PLT > 1,000)
K+ moves out of WBC’s, PLT’s after clotting
If suspected—order STAT serum/plasma K+ levels
if serum K+ > plasma K+ by more than 0.3mEq/L, suspect pseudohyperkalemia
In any case, have low threshold to repeat labs

41. Approach to Hyperkalemia
Step 2: If real, why did it happen?
Acute or chronic renal failure
Medications (K+ sparing diuretics, ACE inhibitors, ARB’s, BB’s, digoxin, etc.)
Endocrinopathies
K+ supplements or salt substitutes
K+ in IV infusions/TPN

42. Approach to Hyperkalemia
Step 3: Is this an emergency?
How high is the potassium level?
If serum K+ > or = 6.0 mEq/L, then treat as emergency
Are there any EKG changes consistent with hyperkalemia-induced cardiac instability?
If yes, then treat as emergency
Remember, the lack of EKG changes is NOT always entirely reassuring

43. Approach to Hyperkalemia
Step 3 (con’t): EKG assessment
Four stages of EKG changes
Peaked T waves
PR prolongation
QRS widening
Sine waves
PEA or asystole

44. Approach to Hyperkalemia
Step 4: Emergency Rx
Part A: oppose toxic effects on cell membrane
IV calcium infusion (gluconate preferred over chloride)
Less toxic effects if IV extravasation
Give 1-2, 10mL ampules of 10% Calcium gluconate over 2-5 minutes
Keep EKG machine attached to patient!!!
EKG changes will diminish in 1-3 minutes
Action: Stabilization of cardiac cells. Does not lower potassium. Used for hyperkalemia with EKG changes.
If EKG changes do not immediately resolve, dose can be repeated in 5 minutes.

45. Approach to Hyperkalemia
Step 4 (con’t): Emergency Rx
Part B: Shift K+ into cells
Will buy you 1-4 hours before direct elimination methods “kick-in”
Insulin/dextrose therapy
Give 10U regular insulin IV push, together with 1 ampule (50mL) D50 IV push
Follow this with a D 5 containing IV maintenance fluid for several hours.
Effect within 15 minutes.
Peak effect 60 min. Duration 3-4 hours.
Adjuncts
Beta agonist:
Albuterol nebulizer
Peak effect in 90 minutes
Sodium bicarbonate 1 ampule IV push
Onset: 30 minutes
Duration: minutes

46. Approach to Hyperkalemia
Step 5: Emergency or non-emergency therapy (usually takes 4-6 hours to work)
Direct elimination of K+ from body
Sodium polystyrene sufonate (K+ binding resin) plus sorbitol
Give Kayexalate gm
PO if patient can tolerate
PR (retention enema) if upper GI problems
Patient needs to have a colon for this to work!
Hemodialysis as last resort or in severe cases

47. Summary: Hyperkalemia
Make sure it’s real
Determine emergent or not
Degree of hyperkalemia, EKG
Treat emergent cases with calcium gluconate, insulin, dextrose, and kayexalate +/- dialysis
Monitor closely for response to treatment—watch for rebound
Fix the cause if possible