Assorted electrolytes

Question 1

Sodium

Answer 1

• Mainly in ECF
• Excreted via kidneys
• Changes in concentration affect BP and intracellular fluid composition and volume
• <1% normally excreted
• Increase in blood osmolality = increase in ADH = water reabsorption and decreased urinary output
• High sodium = hypertonic hyponatraemia
• Low sodium = hypotonic hyponatraemia (caused by hypovolaemia which is when there is less water AND sodium or euvolaemia where there is more water but no change in sodium)

Question 2

Hyponatraemia causes

Answer 2

Diuretics, diarrhoea, heart failure, liver disease, renal disease, bad ADH secretion

Question 3

Hyponatraemia symptoms

Answer 3

Headache, lethargy, dizziness, confusion

Question 4

Hypernatraemia symptoms

Answer 4

Fever, thirst, dry mucous membranes, restlessness

Question 5

Causes of hypernatraemia

Answer 5

Dehydration and diuretics

Question 6

Potassium

Answer 6

• Produced high K+ intracellularly
• Negative intracellular potential = RMP
• Kidneys maintains K+ balance
• 90% reabsorbed
• K+ exchanged for H+ in intercalated cell, stimulated by acidosis and low potassium conc
• Secretion of potassium and reabsorption of sodium in principal cells stimulated by aldosterone, increased [K+], alkalosis and increased tubular flow
• Located intracellularly

Question 7

Hypokalaemia causes

Answer 7

Alkalosis, insulin, diarrhoea, renal loss, hyperaldosteronism

Question 8

Symptoms of hypokalaemia

Answer 8

Skeletal muscle weakness, loss in smooth muscle tone, bradycardia

Question 9

Treatment of hypokalaemia

Answer 9

IV K+

Question 10

Causes of hyperkalaemia

Answer 10

Tissue damage, acidosis, aldosterone impairment (spironolactone, Addison’s)

Question 11

Symptoms of hyperkalaemia

Answer 11

Neuromuscular irritability, restlessness, intestinal cramping, loss of muscle tone, paralysis
Causes ECG changes - sine wave and Kussmaul breathing (hyperventilation), T waves taller, P waves disappear

Question 12

Treatment of hyperkalaemia

Answer 12

Diet and medication adjustment but if severe, administer insulin an glucose

Question 13

What does calcitonin do?

Answer 13

Increases osteoblast activity

Question 14

Causes of hypocalcaemia

Answer 14

Nutritional deficiency, vit D deficiency, hypoparathyroidism, kidney failure, hyperventilation

Question 15

Symptoms of hypocalcaemia

Answer 15

Confusion, muscle spasm, paraesthesia, drowsiness, coma

Prolonged QT interval

Question 16

Treatment of hypocalcaemua

Answer 16

Oral calcium and vit D needed, IV in severe cases

Question 17

Causes of hypercalcaemia

Answer 17

Hyperparathyroidism, excess vit D, malignancy

Question 18

Symptoms of hypercalacemia

Answer 18

Stones, bones, moans, groans

Short QT syndrome, depressed T waves, hypertension, kidney stones

Question 19

Treatment of hypercalcaemia

Answer 19

Reduce calcium in diet or PTH

Question 20

Causes of hypophosphataemia

Answer 20

Reduced intestinal absorption, primary hyperparathyroidism, osteomalacia, rickets

Question 21

Symptoms of hypophosphataemia

Answer 21

Muscle weakness, confusion, hallucinations, convulsions

Left shift of oxy-haem dissociation curve, arrythmias, heart failure

Question 22

Treatment of hypophosphataemia

Answer 22

Oral or IV phosphate

Question 23

Causes of hyperphosphataemia

Answer 23

CKD

Question 24

Symptoms of hyperphosphataemia

Answer 24

Associated with calcium depletion due to calcium phosphate formation (precipitates in lungs, kidneys, joints)

Question 25

Treatment for hyperphosphataemia

Answer 25

Reduce dietary phosphate or start dialysis

Question 26

Causes of hypomagnesaemia

Answer 26

Malnutrition, defective gut absorption, urinary loss, alcoholism, diuretics

Question 27

Symptoms of hypomagnesaemia

Answer 27

Irritability, tremor, ataxia, hyperreflexia, confusion, hallucinations, convulsions Causes QRS widening, PR interval prolongation, flat T waves

Question 28

Causes of hypermagnesaemia

Answer 28

Kidney disease, magnesium containing laxatives or antacids

Question 29

Symptoms of hypermagnesaemia

Answer 29

Depressed muscle contraction and nerve function, narcosis, respiratory paralysis, cardiac conduction defects ECG changes = long QT, bradycardia and heart blocks

Question 30

How is a decrease in BP corrected?

Answer 30

Heart decreases release of ANP Kidney increases renin and angiotensin secretion to produce aldosterone Pituitary increases ADH secretion

Question 31

Isotonic hyponatraemia

Answer 31

Normal conc

Question 32

Hypertonic hyponatraemia

Answer 32

High conc