Fluid and electrolytes

Question 1

Normal level of sodium and function

Answer 1

Level: 135-145 mEq/L

Function: Regulating fluid balance and brain/muscle/nerve contractility

Question 2

Where sodium goes…

Na? Think….

Answer 2

Where sodium goes, water will follow

Na? Think neuro!!
*Seizure precautions for hypo and hypernatremia

Question 3

Risks of hyponatremia

Answer 3

• Delirium
• Seizure / Coma
• Cerebral oedema
• Rhabdomyolosis (Rapid muscle breakdown)
• Death

You might wonder why hyponatremia causes cerebral oedema as it defies osmosis. However, in hyponatremia, as sodium levels are low in serum, water will then travel into the cells as water follows sodium, therefore causing brain swelling.

Question 4

Risks of hypernatremia

Answer 4

• Delirium
• Seizure /coma
• Myoclonus (Muscle twitching)
• Death

Question 5

What is rhabdomyolosis?

Answer 5

Rhabdomyolosis is the breakdown of muscle due to:
• Severe muscle injury
• Dehydration and overheating
• Medications such as benzodiazipines (Diazepam, temazepam etc), statins, antidepressants (amitryptiline) and can be induced by illicit drug use (cocaine, LSD, amphetamines like meth, MDMA)

Rhabdomyolosis is very toxic to the kidneys as cell breakdown releases myoglobin which is toxic to kidneys. Rhabdomyolosis can also lead to severe electrolyte imbalances as cellular electrolytes are released into the bloodstrem.

Symptoms:
• Dark urine (+ myoglobinuria)
• Increase CK (10k units/L +) in blood
• Muscle weakness and soreness
• Muscle swelling

Treatments:
• IV fluids to flush out toxins and correct electrolyte abnormalities
• Dialysis in severe AKI
• Physio

Question 6

Normal level and functions of potassium (3)

Answer 6

Normal level: 3.5 - 5 mEq/L

Function:
- Maintains INTRAcellular osmolality (K+ is most abundant in cells rather than serum)

• Maintains heart rhythm
• Maintains muscle and skeletal contractions

Question 7

Function of aldosterone

Answer 7

Aldosterone is a hormone that helps the kidneys control how much water and sodium the body holds. Usually aldosterone helps with the re-absorption of Na+ and water, and excretes potassium.

Question 8

How does hyperkalemia affect the heart rhythm as we as vital organs such as the lungs, GI tract etc?

Answer 8

Heart rhythm: Hyperkalemia can disrupt the heart rhythm and can manifest differently from a normal EKG:

• flattened P wave, Prolonged PR interval, widened QRS complex and ST elevation/Tall T wave

Due to the rhythm changes, hyperkalemia can result in ventricular tachycardia and ventricular fibrillation.

As stated earlier, potassium is responsible in maintaining skeletal and muscle contractions. In hyperkalemia, the increase in potassium can result in increased tension within muscules which can disrupt its normal functioning. Patient’s with hyperkalemia can experience muscle weakness, decreased urine production, decreased heart contractions etc.

Question 9

Interventions for hyperkalemia

Answer 9

Initial intervention:
- Insulin & dextrose 5% to move K+ back into the cells from the bloodstream
- Calcium gluconate: Slow down heart rate to help heart pump more efficiently
- Lasix: Furosemide to flush K+ via urine
- Kayaxelate: Binds with K+ and helps with the excretion of K+ via stool (Make sure commode or toilet is near!)
- Albuterol: Can also shift K+ into cells, HOWEVER, contra-indicated if the patient has existing heart issues as can increase HR further and cause palpitations

• Stop meds containing K+ such as or bad for kidneys:
• Dialysis in severe cases
• Low K+ diet: Avoid potatoes, oranges, tomatoes, avocados, strawberries, spinach, fish