navigating the ups and downs of electrolyte management

MICHAEL KENNEDY RPH, PHARMD

Navigating the Ups and Downs of Electrolyte Management

Learning Objectives

• Demonstrate an understanding of the relationship between various

electrolytes

• Identify electrolyte levels which require management

• Describe replacement strategies for abnormal electrolyte levels including

potassium, magnesium, calcium, phosphate, and sodium

• Select an appropriate therapy for electrolyte replacement

Disclosures

Will be provided with an honorarium from PANL for presenting

Potassium

Potassium

Found in many fruits and

vegetables including

apricots, bananas,

potatoes, soybeans, and

lentils

Normal range is 3.5-

5.0mmol/L

Hypokalemia

Typically defined as K+ <3.5 mmol/L

Causes

Diet

Medications such as diuretics

Diarrhea

Vomiting

Other electrolyte imbalances (magnesium)

Often discovered on routine bloodwork only vs symptomatic

May present as muscle weakness

ECG changes (prolonged QTc)

Presentation:

3.0-3.4mmol/L – usually asymptomatic

2.5-2.9mmol/L –asymptomatic/muscle weakness/ECG changes

<2.5mmol/L – more urgent cases, QTc changes/risk of MI increases

Hypokalemia Treatment Strategies

IV preparations

10mmol/20mmol mini-bags

Various 1000ml K+ bags

Orally

Slow K 600mg tablet

Micro K 600mg tablet

K-Dur 1500mg tablet

K-Lyte 25 mEq tablet

Liquid K-10 solution

Keep patient factors in mind

Liquid vs capsule vs tablet

IVF assessment important

D5W will cause insulin spike – can make hypokalemia worst

Assess IV access

10mmol IV max if peripherally

20mmol IV acceptable if given via

central line

Patients will report a burning

sensation if given too quickly

Hyperkalemia

Defined as K+ >5.0mmol/L

causes

Medication use

ACE/Septra

K+ sparing diuretics

Tissue breakdown

Overcorrection of hypokalemia

Renal dysfunction

Presentation:

5.1-5.4mmol/L – often

asymptomatic

5.5-6.5mmol/L – moderate

hyperkalemia, may present with

chest pain, nausea/vomiting

>6.5mmol/L – requires prompt

treatment, arrythmia

development/increased risk of MI

Hyperkalemia Treatment Strategies

Kayexalate

Calcium

Insulin + Glucose

Salbutamol

Loop diuretics

Dialysis

Often treatment strategies are combined

For example Insulin + Glucose + Salbutamol + IV Calcium together

Clinical Pearl

Kayexalate works by exchanging sodium ions for potassium ions in

the GI tract before it is eliminated from the body via stool

Ensure patient is moving bowels or has medications available to help

pass stool before giving kayexalate

Common strategy involves giving Kayexalate 30g po x 1 dose +

Lactulose 30ml po x 1 dose.

Magnesium

Magnesium

Found in almonds,

seafood, berries, bananas,

green leafy vegetables,

and even coffee (woo!)

Normal range 0.66-1.07

mmol/L

Hypomagnesemia

Defined as serum magnesium

<0.66 mmol/L

Causes

Renal failure

Malabsorption via GI tract

Alcohol

Medication use

Chemotherapy

Digoxin

Cyclosporin/tacrolimus

Aminoglycosides

Outcomes:

Tremors

Weakness

Delirium

Arrythmia development

Hypokalemia

Hypomagnesemia Treatment

Strategies

IV preparations

Magnesium sulfate

1g, 2g, 4g

Oral magnesium

Magnesium oxide

Magnesium citrate

Magnesium glucohyptenate

Hypermagnesemia

Defined as serum magnesium

>1.07mmol/L

Causes

Renal failure

Overcorrection from

hypomagnesemia therapy

Often a rare occurrence in the

absence of the above two causal

factors

Outcomes

Nausea/vomiting

Drowsiness

Hypotension/bradycardia

Muscle paralysis

Cardiac arrest

Hypermagnesemia Treatment

Strategies

Isotonic solutions IV (Normal saline infusion to aid in kidney function)

Loop diuretics

Dialysis

Clinical Pearl

Use IV preparations for more severe hypomagnesemia as oral preparations are poorly absorbed and can lead to diarrhea (thus more electrolyte imbalance)

Ensure rate of magnesium IV is appropriate (typically 1g IV per hour). Too quick will result in inability to absorb dose before eliminating from body

Potassium and Magnesium

Relationship

Hypomagnesemia leads to increased renal elimination of

potassium.

Attempting to correct potassium while hypomagnesemia present

often leads to repeated dosing/failure to correct/increased cost

and adverse effects associated with hypokalemia therapy

Can often correct mild hypokalemia by correcting hypomagnesemia

If both magnesium and potassium levels are low, attempts to correct

magnesium first should be made

Calcium

Calcium

Found in dairy products,

dark green vegetables

such as spinach, nuts,

and fortified products

(such as orange juice)

Normal range 2.15-2.62

mmol/L

Hypocalcemia

Defined as serum calcium <2.15

mmol/L

Causes

Medications

Bisphosphonates

Calcium binders

Chemotherapy

Renal failure

Hormonal imbalances

Hypomagnesemia

Outcomes

numbness in hands and feet,

muscle cramps, confusion, loss of

consciousness, seizures

Hypocalcemia Treatment

Strategies

Oral replacement

Calcium carbonate

Calcium citrate

Ensure spacing between doses to

allow for elemental iron absorption

(absorption tends to be highest

with doses of 500mg elemental

calcium or less)

Ensure vitamin D deficiency is

ruled out if long term calcium

replacements are an issue

IV replacement

Calcium gluconate

Calcium chloride

Calcium chloride offers 3x as

much elemental calcium vs

gluconate, but is also more likely

to cause tissue necrosis if

extravasation occurs

Hypercalcemia

Defined as serum calcium

>2.62mmol/L

Causes

Malignancy

Often seen in multiple myeloma

Too much oral intake?

Unlikely to cause hypercalcemia due to the inhibition of PTH release and decreased calcitriol synthesis

Increased PTH levels

Increased osteoclast activity

Outcomes

Mild: often asymptomatic

Moderate: polyurea, polydipsia,

nausea/vomiting, constipation

Severe: confusion, cognitive delay,

coma

Hypercalcemia Treatment

Strategies

IV fluid (Normal Saline) to ensure

adequate renal function

Calcitonin (salmon)

Denosumab

Bisphosphonates

Zoledronic acid

Pamidronate

Avoidance of high calcium

containing foods and vitamin D

supplementation important during

initial phase of correction

Be careful not to overshoot!

Clinical Pearl Ionized calcium levels

Ionized calcium is the most active form of

calcium (calcium not attached to proteins)

Ionized calcium is more reflective of a true

calcium level in a patient versus serum

calcium

If a patient has low albumin (<20g/L),

perform an ionized calcium level to rule out

hypocalcemia versus correcting calcium

levels based upon albumin

Ionized calcium uses a different reference

range versus serum calcium

Normal range: 1.18-1.32mmol/L

Phosphate

Phosphate

Found in eggs, yogurt,

salmon, chicken, sunflower

seeds, red meats, cola

Normal range 0.74-1.52

mmol/L

Hypophosphatemia

Defined as serum phosphate <0.74

mmol/L

Causes

Medications

antacids

Phosphate binders

IV iron

Inadequate intake

Vitamin D deficiency

Outcomes

Mild/moderate deficiency usually

asymptomatic

Severe cases can present with

decreased level of consciousness,

seizures, coma

Hypophosphatemia Treatment

Strategies

IV replacement

Available as potassium phosphate

IV

Oral replacement

Phosphate Novartis tablets

Jamp sodium phosphate tablets

and IV options when replacement

is needed in moderate to severe

cases

Oral replacements are given as

effervescent tablets

Be aware of patient at hand!

Hyperphosphatemia

Defined as serum phosphate >1.52

mmol/L

Causes

Medication use

Penicillin

Corticosteroids

Acute/chronic kidney disease

Tumour lysis syndrome

Rhabdomyolysis

Outcomes

Muscle cramping, numbness,

tingling, symptoms resulting from

subsequent hypocalemia

Hyperphosphatemia Treatment

Strategies

Acute hyperphosphatemia

IV fluid (Normal Saline) to support kidney function

Dialysis correction

IV calcium (rare cases)

Chronic hyperphosphatemia

(typically in CKD)

Phosphate restrictive diets

No Coke or Pepsi

Phosphate binders

Calcium containing Vs Non-calcium containing phosphate binders

Clinical Pearl Ensure phosphate levels are assessed early

as replacements can often take 8 hours or

more

IV potassium phosphate often given over 4

hours per replacement (unless in critical care

unit)

Patients with limited IV access can be

delayed replacing phosphate due to

multiple other medications needing access

Calcium and Phosphate Relationship

Inversely related

Low calcium = high

phosphate

High phosphate = low

calcium

Sodium

Sodium

Found in processed meats,

cheeses, sauces (i.e soy

sauce), and naturally (i.e

sea salt)

Normal range 135-145

mmol/L

Hyponatremia

Defined as serum sodium <135

mmol/L

Causes

Medications

Diuretics

Amiodarone

Carbamazepine

Amitriptyline

Exercise-induced

Water overdose!

Outcomes

Mild: headache, lethargic,

nausea/vomiting

Severe: symptoms usually

secondary to cerebral edema

Drop in serum osmolality results in an intracellular fluid shift thus leading to edema

Hyponatremia Treatment Strategies

Fluid restriction

Diuresis of excess water

Oral preparation

Sodium Chloride tablets (1000mg capsule

IV preparation

Sodium Chloride 3% solution (hypertonic saline)

Hypernatremia

Defined as serum sodium >145

mmol/L

Causes

Medications

Diarrhea

Vomiting

Dehydration

Outcomes

Mild: lethargy, weakness, irritability

Severe: rupture of cerebral veins,

hemorrhage

Hypernatremia Treatment

Strategies

Sodium restriction

Medication review

Volume correction using IV fluid

Often D5W is fluid of choice

Clinical Pearl GO SLOW!

Osmotic Demyelination Syndrome (ODS)

occurs when sodium levels are corrected

too quickly in the setting of hyponatremia

Destruction of the myelin sheath around

nerces found in the brain stem occur

Effects are often not seen until 2-6 days after

quick correction

Often leads to permanent dysfunctions

including changes in behavior,

disorientation, dysphagia, and even coma

The Range Dilemma

Try not to get fixated on the numbers

“I read that 10mmol KCL IV = 0.1mmol correction”

Depending on practice setting, electrolyte replacement can vary,

and the concept of “mild/moderate/severe” can change

Critical care

Inpatient Vs Outpatient

Anticipation of treatment effects

Treating the underlying condition

Easy to get lost in trying to correct electrolyte imbalaces day after

day when an underlying uncorrected condition can be a main contributory factor

Diarrhea

Nausea/vomiting

Decreased appetite

Medication interactions

Adherence

Questions

References

Goltzman, D. (2021). Treatment of hypocalcemia. Uptodate. Retrieved October 21 from https://www.uptodate.com/contents/treatment-of-hypocalcemia?search=hypocalcemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Kumon S, Usui R, Kuzuhara S, Nitta K, Koike M. (2017). The Improvement of the Outcome of Osmotic Demyelination Syndrome by Plasma Exchange. Intern Med. Retrieved October 22, 2021, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8267071/

Liamis, G., Milionis, H., Elisaf, M. (2010). Medication-induced hypophosphatemia: a review, QJM: An International Journal of Medicine. Retrieved on October 23, 2021, from https://academic.oup.com/qjmed/article/103/7/449/1585359

Mount, D. (2019). Clinical manifestations and treatment of hypokalemia in adults. Uptodate. Retrieved October 21, 2021, from https://www.uptodate.com/contents/clinical-manifestations-and-treatment-of-hypokalemia-in-adults?search=hypokalemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Mount, D. (2020). Treatment and prevention of hyperkalemia in adults. Uptodate. Retrieved October 21, 2021, from https://www.uptodate.com/contents/treatment-and-prevention-of-hyperkalemia-in-adults?search=hyperkalemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Shane, E., & Berenson, J. (2020). Treatment of hypercalemia. Uptodate. Retrieved October 21, 2021, from https://www.uptodate.com/contents/treatment-of-hypercalcemia?search=hypercalcemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

References

Sterns, R., Hoorn, E. (2021). Treatment of hypernatremia in adults. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/treatment-of-hypernatremia-in-adults?search=hypernatremia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Sterns, R. (2021). Overview of the treatment of hyponatremia in adults. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/overview-of-the-treatment-of-hyponatremia-in-adults?search=hyponatremia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Stubbs, J., Yu, A. (2021). Overview of the causes and treatment of hyperphosphatemia. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/overview-of-the-causes-and-treatment-of-hyperphosphatemia?search=hyperphosphatemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Liamis, G., Milionis, H., Elisaf, M. (2010). Medication-induced hypophosphatemia: a review, QJM: An International Journal of Medicine. Retrieved on October 23, 2021, from https://academic.oup.com/qjmed/article/103/7/449/1585359

Yu, A. (2020). Hypomagnesemia: Evaluation and treatment. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/hypomagnesemia-evaluation-and-treatment?search=hypomagnesemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Yu, A., Gupta, A. (2020). Hypermagnesemia: Causes, symptoms, and treatment. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/hypermagnesemia-causes-symptoms-and-treatment?search=hypermagnesemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1

Yu, A., Stubbs, J. (2021). Hypophosphatemia: Evaluation and treatment. Uptodate. Retrieved on October 22, 2021, from https://www.uptodate.com/contents/hypophosphatemia-evaluation-and-treatment?search=hypophosphatemia%20treatment&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1