This slide was first presented during the Malaysian 1st Emergency Medicine Annual Scientific Meeting, in conjunction with the Academy of Medicine Malaysia, Academy of Medicine Singapore and the Academy of Medicine Hong Kong Tripartite Meeting in Aug 2016.

1. Life Threatening
Electrolyte Abnormalities
Dr. Chew Keng Sheng
Professor/Emergency Physician,
Faculty of Medicine and Health Sciences,
Universiti Malaysia Sarawak
1

2. Objectives
1. Hyperkalemia
a. Basic science - potassium adaptation (feedforward control)
b. Pseudohyperkalemia
c. Clinical features
d. Treatment
2. Hypokalemia
3. Hyponatremia
a. Adjusting serum sodium according to glucose level
b. Formula for calculating sodium deficits - the caveat
c. Goal and rate of correction
2

3. Hyperkalemia
3

4. The role of Aldosterone
revisited
Aldosterone stimulates renal K+ excretion
only at supraphysiological levels, with
little effect within the physiological range of
K+
A kaliuretic reflex arising from receptors in
the gut, portal vein or liver (?).
Rabinowitz, L. Aldosterone and potassium homeostasis.
Kidney Int 49.6 (1996): 1738-1742.
4

5. Youn, J.H. and McDonough, A.A. "Recent advances in understanding integrative control of potassium
homeostasis." Annual review of physiology 71 (2009): 381-401. 5

6. The ‘gut feeling’ is literally telling us that it is not easy to
get hyperkalemia in a normal healthy individual!
Image source: pixabay.com
6

7. Potassium Adaptation
Potassium Adaptation: enhanced
efficiency of potassium excretion when
potassium intake is increased
Hyperkalemia is a rare occurrence in
normal individuals because of
potassium adaptation
Youn, J.H. and McDonough, A.A. "Recent advances
in understanding integrative control of potassium
homeostasis." Annual review of physiology 71
(2009): 381-401.
7

8. What do we know
1. Increasing potassium intake alone is not a common cause of hyperkalemia
unless it occurs acutely
2. Persistent hyperkalemia means impaired urinary potassium excretion (e.g.
reduction in aldosterone secretion or responsiveness, acute or chronic kidney
disease, etc)
3. Large release of potassium from the cells (increased tissue breakdown)
causing a transient elevation
8

9. Pseudohyperkalemia
9

10. Pseudohyperkalemia
Traumatic hemolysis from venipuncture (can be
up to 20% of samples). Lab reports as “slightly
hemolyzed”
Release from muscle cells distal to a tourniquet
with fist clenching
Common in cases of leucocytosis (TWC > 50,000
- 100,000/mm3
) or thrombocytosis (>500,000 - 1
million/mm3
)
10

11. Effects of fist clenching
Don BR et al (1990): Both repeated fist clenching
and isometric handgrip increased the plasma
potassium level by as much as 1.6 mmol/l from the
contracting arm.
Don, Burl R et al. "Pseudohyperkalemia caused by fist
clenching during phlebotomy." New England Journal of
Medicine 322.18 (1990): 1290-1292.
Solid circles represent patients,
open circles represent controls
11

12. Thrombocytosis
Potassium moves out of platelets after clotting has occurred. Therefore, serum
potassium is normally higher than plasma potassium by 0.1 - 0.5 mmol/l
Graber et al (1988): N = 283 controls and 161 patients with reactive
thrombocytosis.
Hyperkalemia noted in 34% of patients with a platelet count >500,000/mm3
vs 9%
of patients with a platelet count less than 250,000/mm3
An increase of K+ level of 0.15 mmol/l for every increase of 100,000/mm3
in the
platelet count.
Graber, Mark et al. "Thrombocytosis elevates serum potassium." American Journal of Kidney Diseases 12.2
(1988): 116-120.12

13. Leucocytosis
High white blood cell counts (>120,000/mm3
) (e.g., due to chronic lymphocytic
leukemia) causes pseudohyperkalemia due to cell fragility.
May be more prominent when blood is sampled in heparinized tubes
Centrifugation of a heparinized tube causes in vitro cell destruction and release of
potassium
Lee, Hong-Kee et al. "Pseudohyperkalemia—is serum or whole blood a better specimen type than
plasma?." Clinica Chimica Acta 396.1 (2008): 95-96.
13

14. Exclude pseudohyperkalemia
Suspect when there no apparent cause for
hyperkalemia in an asymptomatic patient
Look for wide variability in repeated
measurements of K+ level
Attempt venipuncture without a tourniquet,
repetitive fist clenching. If a tourniquet is required,
release tourniquet after needle insertion. Then
waiting for about one minute (or 2) before drawing
the blood sample.
14

15. Clinical Features
15

16. Clinical Features
Vague symptoms, may be overshadowed by primary illnesses that precipitate the
hyperkalemia
Most serious manifestations - muscle weakness or paralysis, cardiac conduction
abnormalities, and cardiac arrhythmias
Usually occur when the serum potassium concentration is ≥7.0 mmol/l
Absence of symptoms do not rule out hyperkalemia
16

17. Muscle Weakness
Muscle weakness may mimic Guillain-Barré syndrome - ascending muscle
weakness that begins with the legs and progresses to the trunk and arms
Sphincter tone and cranial nerve function are typically intact
Symptoms resolve with correction of the hyperkalemia.
17

18. ECG Manifestations
ECG manifestations depends on:
● the absolute se K+ level
● the rate of increase
Alfonzo, Annette VM et al. "Potassium disorders—clinical
spectrum and emergency management." Resuscitation 70.1
(2006): 10-25.
Note:
progression and severity of ECG changes do
not correlate well with the serum potassium
concentration 18

19. ECG Manifestations
In a retrospective review of 90 hypokalemic patients by Montague et al (2008),
although the probability of ECG abnormalities increased with increasing serum
potassium, but the ECG was insensitive for the diagnosis of hyperkalemia.
Szerlip et al (1986) reported 2 cases of severe hyperkalemia >9.0 mmol/l with no
expected ECG manifestations
Szerlip, Harold M, James Weiss, and Irwin Singer. "Profound hyperkalemia without electrocardiographic
manifestations." American Journal of Kidney Diseases 7.6 (1986): 461-465.
Montague, Brian T, Jason R Ouellette, and Gregory K Buller. "Retrospective review of the frequency of
ECG changes in hyperkalemia." Clinical Journal of the American Society of Nephrology 3.2 (2008):
324-330.
19

20. ECG Manifestations
Seen commonly when se K+ >5.5
mmol/l
Earliest ECG manifestation is
narrow-based, peaked T waves
(vs broad-based T waves in
myocardial infarction or
intracranial lesions)
Best seen leads II, III, V2 - V4
Only 22% of patients Parham, Walter A et al. "Hyperkalemia revisited." Texas Heart Institute
Journal 33.1 (2006).
Image Graphic 80441 Version 5.0 from UptoDate
20

21. As the hyperkalemia gets more severe, there is progressive lengthening of the PR
interval and QRS duration
When se K+ level reaches 8 - 9 mmol/l, SA node may stimulate the ventricles
directly without evidence of atrial activity. This is because the SA node is less
susceptible to the effects of hyperkalemia; the absence of P wave and widened
QRS mimics ventricular tachycardia
When se K+ reaches 10 mmol/l, the progressively widened QRS merges with T
wave producing sine wave
Parham, Walter A et al. "Hyperkalemia revisited." Texas Heart Institute
Journal 33.1 (2006).
ECG Manifestations
21

22. Management in Emergency
Department
22

23. Calcium
Hyperkalemia-induced depolarization of the
resting membrane potential leads to
inactivation of sodium channels and
decreased membrane excitability
Calcium restores the gap between resting
membrane potential to the threshold potential
Effect seen within 1 min, last 30 - 60 minutes
Calcium gluconate vs calcium chloride
Solid line - normal action
potential
Dotted line- hyperkalemic effect
Parham, Walter A et al. "Hyperkalemia revisited." Texas Heart Institute Journal 33.1 (2006).23

24. Insulin
Insulin works by stimulating Na-K-ATPase pump to drive potassium into the cells
Independent of its effect on glucose.
Glucose administration is to prevent hypoglycemia (not always necessary if se
glucose >13 mmol/l)
Glucose without insulin may cause paradoxical effect by increasing plasma
osmolality, drawing water and K+ out of cells
Alfonzo, Annette VM et al. "Potassium disorders—clinical spectrum and emergency management."
Resuscitation 70.1 (2006): 10-25.
24

25. Insulin
Effect begins in 10 to 20 min, peaks at 30 to 60 minutes, and lasts for 4 - 6 hours
Reduce potassium by 0.6 - 1.0 mmol/l
Renal failure patients maybe resistant to the glucose-lowering effect of insulin, but
the hypokalemic effect of insulin is still intact because Na-K-ATPase activity can
still be enhanced
Alvestrand, A et al. "Insulin-mediated potassium uptake is normal in uremic and healthy subjects."
American Journal of Physiology-Endocrinology and Metabolism 246.2 (1984): E174-E180.
25

26. Salbutamol
A beta-2 agonist drives potassium into the cells by increasing the activity of the
Na-K-ATPase pump
Lowers se K+ level by 0.6 - 1.0 mmol/l
Nebulized form requires much higher dose than dose for asthma (10 - 20 mg vs
2.5 - 5 mg for asthma)
Effect begins in 10 to 20 min, peaks at 30 to 60 minutes, and lasts for 4 - 6 hours
Alfonzo, Annette VM et al. "Potassium disorders—clinical spectrum and emergency management."
Resuscitation 70.1 (2006): 10-25.
26

27. Combined salbutamol + insulin-glucose?
Allon & Copkney (1990):
● insulin with glucose alone: reduced 0.65 +/- 0.09 mmol/l
● salbutamol alone: reduced 0.66 +/- 0.12 mmol/liter
● combined regimen: reduced 1.21 +/- 0.19 mmol/l;
● (p < 0.02)
Alfonzo, Annette VM et al. Potassium disorders—clinical spectrum and emergency management.
Resuscitation 70.1 (2006): 10-25.
Allon, Michael, and Charles Copkney. Albuterol and insulin for treatment of hyperkalemia in hemodialysis
patients. Kidney international 38.5 (1990): 869-872.
27

28. Sodium bicarbonate
More of historical interest
For persistent metabolic acidosis.
In a study by Blumberg et al (1992) on 12 dialysis patients (se K+ of 5.25 - 8.15
mmol/l) received IV bicarbonate over a 6-hour period. No change of potassium
level noted during first 4 hours. Only at four and six hours did a moderate decline
to 5.44 mmol/l (p<0.05) and to 5.30 mmol/l (p<0.01) noted respectively. In 3
patients, no or minimal change noted even after 6 hours
Blumberg, Alfred, Peter Weidmann, and Paolo Ferrari. Effect of prolonged bicarbonate administration on
plasma potassium in terminal renal failure." Kidney international 41.2 (1992): 369-374.
28

29. Hypokalemia
29

30. Introduction
Generally, se K+ decreases by 0.3 mmol/l for every 100 mmol reduction in total
body potassium
Muscle weakness usually does not occur at se K+ level >2.5 mmol/l unless it
develops acutely.
Many hypokalemic patients are also deficient in magnesium. Magnesium is
important for potassium update and for maintenance of intracellular K+ level,
particularly in the myocardium
Alfonzo, Annette VM et al. Potassium disorders—clinical spectrum and emergency management.
Resuscitation 70.1 (2006): 10-25.
30

31. A note on hypomagnesemia
● Can be subtle, commoner than expected - 12% in hospitalized patients (Agus
1999), 65% in ICU patients (Tong & Rude, 2005)
● Neuromuscular - tremor, tetany, convulsions, weakness, delirium, and coma,
etc
● Cardiovascular - widened QRS and peak, tall T waves, then widened PR
interval and ventricular arrhythmias with severe cases
● Accompanying hypocalcemia, hypoparathyroidism, hypokalemia
31
Tong, G.M, and Rude, R.K.. Magnesium deficiency in critical illness. Journal of Int Care Med 20.1 (2005): 3-17.
Agus, Zalman S. Hypomagnesemia.Journal of the American Society of Nephrology 10.7 (1999): 1616-1622.

32. Treatment of hypokalemia
2 g KCl in 200 ml over 2 hours or 1 g KCl in 100 ml over 1 hour
[1 g KCl = 13 mmol/l of potassium]
Rates as high as 40 mmol/hour may be required for life-threatening patients
Advising patient just to increase intake of potassium-rich foods,
such as oranges and bananas may not be effective enough
because dietary potassium is predominantly in the form of
potassium phosphate or potassium citrate which results in the
retention of only 40% as much potassium as KCl.
Image source: https://www.flickr.com/photos/codex41/9725166177 32

33. Hyponatremia
33

34. Classification
1. Hypertonic hyponatremia
a. Hyperglycemia
i. osmotic shift of water from ICF to ECF
ii. Need to do correction
2. Isotonic hyponatremia
a. Hyperlipidemia - Pseudohyponatremia
i. Relatively larger relative proportion of
plasma volume occupied by excess lipids
3. Hypotonic hyponatremia
a. Hypervolemic
b. Euvolemic
c. Hypovolemic
Verbalis JG et al. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am
J Med. 2013;126(10 Suppl 1):S1-42.34

35. Adjusting se sodium level due to glucose level
High glucose load causes osmotic shift - pulls water out of the cells
Se sodium fall by about 1.6 mmol/l for each 5.5 mmol/L increase in se glucose
concentration (Katz 1973)
Se sodium fall by about 2.4 mmol/l for each 5.5 mmol/L increase in se glucose
concentration (Hillier et al, 1999)
Katz MA. Hyperglycemia-induced hyponatremia--calculation of expected serum sodium depression. N
Engl J Med. 1973;289(16):843-4.
Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J
Med. 1999;106(4):399-403.
35

36. 36
Assuming se sodium falls 2.0* mmol/l for every 5.5 mmol/l
(equivalent of 100 mg/dl)
Corrected serum sodium =
Measured serum sodium + [se glucose - 5.5 mmol/l] * (2.0/5.5)
*1.6 mmol/l (Katz 1973), 2.4 mmol/l (Hillier et al, 1999)

37. 37
Formula for predicting sodium deficits
Sodium deficit
= (Desired se sodium - measured se sodium) * Total body water
= (Desired se sodium - measured se sodium) * 0.5ϕ
* body weight
Note:ϕ
some would take 0.6
In 3% NaCl, sodium concentration is approx 500 mmol/l or 1 ml = 0.5 mmol/l [1 g NaCl = 17 mmol/l]
Therefore, every 1 ml per kg body weight of 3% NACl increases se sodium by 1 mmol/l

38. Caveat:
38
Formulas may not accurately predict the magnitude of change in serum sodium.
In a series of 62 patients with a baseline se sodium of 112 mmol/l given hypertonic
saline (Mohmand et al, 2007), 74% had an increase in se sodium higher than what
was expected.
Reasons:
Correction of hyponatremia using hypertonic saline removes the hypovolemic
stimulus of ADH release (unless it is in SIADH)
Mohmand, Hashim K et al. Hypertonic saline for hyponatremia: risk of inadvertent overcorrection. Clinical
Journal of the American Society of Nephrology 2.6 (2007): 1110-1117.

39. Goal of therapy
● A 4- to 6-mmol/L increase in serum is sufficient to reverse the most serious
manifestations of acute hyponatremia (Sterns et al, 2010)
● In emergency therapy, the goal is to rapidly increase the serum sodium by 4
to 6 mmol/L over a period of 6 hours (Sterns et al, 2010)
Sterns RH, Nigwekar SU, Hix JK. The treatment of hyponatremia. Semin Nephrol. 2009;29(3):282-99.
Sterns RH, Hix JK, Silver S. Treating profound hyponatremia: a strategy for controlled correction. Am J Kidney
Dis. 2010;56(4):774-9.
39

40. Indications for emergency therapy
● Patients with severe symptoms due to hyponatremia, such as seizures or
obtundation.
● Patients with symptomatic acute hyponatremia, even if symptoms are mild.
● Patients with hyperacute hyponatremia due to self-induced water intoxication,
even if asymptomatic during initial evaluation (risk of cerebral edema due to
osmotically driven water across blood-brain barrier).
● Symptomatic patients who have either acute postoperative hyponatremia or
hyponatremia associated with intracranial pathology.
Verbalis JG, Goldsmith SR, Greenberg A, Korzelius C, Schrier RW, Sterns RH, et al. Diagnosis, evaluation,
and treatment of hyponatremia: expert panel recommendations. Am J Med. 2013;126(10 Suppl 1):S1-42.
40

41. Rate of correction
● Risk of osmotic demyelination syndrome (ODS) in severe hyponatremia -
when serum sodium concentration was increased > 10 to 12 mmol/L within 24
hours or more than 18 mmol/l within 48 hours (Sterns 1987; Karp & Laureno,
1993)
● Keep the rate of increase below 8 mmol/l over 24 hours (Sterns et al, 2009;
Sterns et al, 2010)
Sterns RH. Severe symptomatic hyponatremia: treatment and outcome. A study of 64 cases. Ann Intern
Med. 1987;107(5):656-64.
Karp BI, Laureno R. Pontine and extrapontine myelinolysis: a neurologic disorder following rapid correction
of hyponatremia. Medicine (Baltimore). 1993;72(6):359-73.
Sterns RH, Hix JK, Silver S. Treatment of hyponatremia. Curr Opin Nephrol Hypertens. 2010;19(5):493-8.41

42. “six a day makes sense for safety; so six
in six hours for severe sx’s and stop”
42

43. 43
Conclusion
1. Hyperkalemia - calcium, insulin, salbutamol are useful (insulin + salbutamol
has synergistic effect)
2. If nebulized salbutamol is used, it is 3 times the normal dose used in asthma.
3. Cranial nerve involvement is not common in hyperkalemia
4. Hyponatremia - remember that it may be higher than expected in the
presence of hyperglycemia
5. formula may be used as a guide, but beware that the rise in sodium may be
higher than expected due to diuresis
6. More important is to know the goal: six a day makes sense, so six in six in
severe sxs and stop

44. 44