Electrolyte Disturbances

Question 1

What might you see on an ECG of a patient with hypokalaemia?

Answer 1

Flattened or inverted T waves, U waves, ST depression, atrial arrhythmias

Question 2

Patient has come in with malaise and N/V. On bloods her urea & Cr are raised. UO has not be monitored. What is wrong and what could the resulting electrolyte disturbance be?

Answer 2

Suspected AKI. Poss hyperkalaemia as not being excreted.

Question 3

Sx: N + V, headache, confused
DH: furosemide for CHF

Likely e- abnormality?

Answer 3

Hyponatraemia due to hypovolaemia from diuretics. Na excreted from kidneys.

Question 4

What are the symptoms of hypokalaemia?

Answer 4

Weakness, cramps, parasthesia, hypotonia, palpitations, arrhythmias, nausea

Question 5

What can cause hypernatraemia?

Answer 5

Fluid loss: burns, diarrhoea, fever, glycosuria, resp losses
Inadequate fluid (water) intake - e.g. in elderly
Too much intake: fluids (saline), Conns, bushings

Question 6

A patient has recently received radiotherapy for a breast cancer. She has since developed tingling around her mouth and twitching of her calk muscles. What could be the cause?

Answer 6

Hypocalcaemia due to tumour lysis syndrome.

Question 7

What is Trousseau’s sign?

Answer 7

Spasm of hand from inflated BP cuff. Due to hypocalcaemia

Question 8

A patient who received 30% burns from a gas explosion has begun to feel weak and has general malaise. They are also very confused. On examination reflexes are exaggerated.

Answer 8

Hypernatraemia.

Question 9

What are the Sx of hypocalcaemia?

Answer 9

Twitching muscles, periorbital tingling, spasm hands and feet, tetany, increased reflexes, dry skin, coarse hair, Trousseau’s + Chvostek’s signs.

Question 10

What are the Sx of hypercalcaemia?

Answer 10

Bone - pain, fractures
Stones - renal
Moans - depression
Groans - abdo pain, vom, constipation

Also weakness, tired thirsty, polyuria

Question 11

How is hypercalcaemia treated?

Answer 11

If acute - rehydration 0.9% saline, 3-6L/24h.
Once rehydrated –> diuretics

If not improved –> IV bisphosphonate, e.g. pamidronate

Question 12

Which e- disturbance can cause long QT?

Answer 12

Hypocalcaemia

Question 13

When might you see U waves on an ECG?

Answer 13

Hypokalaemia

Question 14

What is the management of hypokalaemia?

Answer 14

Add K+ to fluids. No more than 10mmol/hour.

If in ICU - can give neat IV K+ with continuous cardiac monitoring

Question 15

What electrolyte abnormalities can renal failure cause?

Answer 15

Hyperkalaemia (not excreted), hyponatraemia

Question 16

What does aldosterone do? Hence what does Addisons and Conns lead to?

Answer 16

Aldosterone –> Na reabsorption, K excretion
Conns –> high Na, low K
Addisons –> low Na, high K

Question 17

How do you determine whether hypernatraemia is due to volume depletion, overload or euvolaemic?

Answer 17

Look at urine osmolality. >400 = dehydrated, <400 = excess Na