Electrolyte imbalances

Question 1

What is the serum value for hyponatraemia?

Answer 1

Less than 135 mmol/L

Severe hyponatremia being below 120 mEq/L

Question 2

What are the signs and symptoms of hyponatraemia?

Answer 2

Vomiting, headache, short-term memory loss, confusion, lethargy, fatigue, loss of appetite, irritability, muscle weakness, spasms or cramps, seizures, and decreased consciousness or coma

Question 3

What are complications for hyponatraemia?

Answer 3

Cerebral oedema –> Secondary to abrupt sodium losses and free water shift from vascular to interstitial space

Question 4

What are potential causes of hyponatraemia?

Answer 4

Liver failure
Cirrhosis 
Renal failure
Steroids
Water intoxication
Burns
Addisons
Diuretics

Question 5

What is the serum value for hypernatraemia?

Answer 5

Hypernatremia is generally defined as a serum sodium level of more than 145 mmol/L

Severe symptoms typically only occur when levels are above 160 mmol/L

Question 6

What are the signs and symptoms of hypernatraemia?

Answer 6

Thirst

The most important signs result from brain cell shrinkage and include confusion, muscle twitching or spasms. With severe elevations, seizures and comas may occur

Question 7

What are the causes of hypernatraemia?

Answer 7

Inadequate intake of free water associated with total body sodium depletion
Severe diarrhoea
ntake of a hypertonic fluid
Salt poisoning

Question 8

What is the serum value for hyperkalaemia?

Answer 8

Over 5.5 mmol/L

Question 9

What are the signs and symptomsa of hyperkalaemia?

Answer 9

The symptoms of an elevated potassium level are generally few and nonspecific

Question 10

What ECG changes are associated with hyperkalaemia?

Answer 10

1. Peaked T waves
2. P wave flattening
3. PR prolongation
4. Wide QRS

Question 11

What are the causes of hyperkalaemia?

Answer 11

Ineffective elimination
Excessive release from cells (insulin deficiency)
Excessive intake

Question 12

What are the signs and symptoms of hypokalaemia?

Answer 12

Severe hypokalemia, with serum potassium concentrations of 2.5–3 meq/L, may cause muscle weakness, myalgia, tremor, and muscle cramps (owing to disturbed function of skeletal muscle), and constipation

Question 13

What are the causes of hypokalaemia?

Answer 13

Inadequate potassium intake
GI or skin losses
Urinary losses
Distribution away from extracellular fluid

Question 14

What ECG changes are associated with hypokalaemia?

Answer 14

1. T wave inversion
2. ST depression
3. Prominent U wave

Question 15

What ECG changes are associated with hypocalcaemia?

Answer 15

1. prolonged ST segment

2. prolonged QT interval

Question 16

What ECG changes are associated with hypercalcaemia?

Answer 16

1. Shortened ST segment

2. Widened T wave

Question 17

What ECG changes are associated with hypomagnesemia?

Answer 17

1. Tall T wave

2. ST depression

Question 18

What ECG changes are associated with hypermagnesemia?

Answer 18

1. Prolonger PR

2. Wide QRS

Question 19

What are the causes of hypercalcaemia?

Answer 19

Primary hyperparathyroidism and malignancy account for about 90% of cases of hypercalcaemia

Lithium use

Question 20

What are the signs and symptoms of hypercalcemia?

Answer 20

Stones - kidney and biliary
Bones - bone pain
Groans - abdominal discomfort
Moans - non-specific symptoms
Thrones - constipation and excessive urination
Muscle tone - muscle weakness

Question 21

What are the signs and symptoms of hypocalcemia?

Answer 21

The symptoms can be recalled by the mnemonic “CATs go numb” - convulsions, arrhythmias, tetany, and numbness in the hands and feet and around the mouth

Question 22

What are the causes of hypocalcaemia?

Answer 22

Hypoparathyroidism (most common)