Dehydration

Question 1

What is the most accurate measure of the degree of dehydration?

Answer 1

The degree of weight loss during diarrhoeal illness

Question 2

What are the three ways that dehydration is assessed as?

Answer 2

1. No clinically detectable dehydration
2. Clinical dehydration
3. Shock

Question 3

Weight loss in no clinically detectable dehydration?

Answer 3

< 5% loss of body weight

Question 4

Weight loss in clinical dehydration?

Answer 4

5 - 10% loss of body weight

Question 5

Weight loss in shock?

Answer 5

> 10% loss of body weight

Question 6

Explain the term ‘Isonatremic dehydration’?

Answer 6

1. The total body deficit of sodium and water is proportional
2. Plasma sodium remains in normal range

Question 7

Explain the term ‘hyponatremic dehydration’?

Answer 7

1. When patients with diarrhoea drink large quantities of water
2. Greater net loss of sodium than water
3. Extracellular plasma sodium concentration falls so there is a higher concentration intracellularly
4. Water moves extracellularly to intercellularly within the cells from low concentration to high concentration

Question 8

What are the symptoms of ‘hyponatremic dehydration’

Answer 8

The movement of water extracellularly to within cells leads to increase in brain volume

** Seizures**

Question 9

Where is hyponatremic dehydration most common?

Answer 9

in poorly nourished infants in developing countries

Question 10

Explain the term ‘hypernatremic dehydration’?

Answer 10

1. Water loss exceeds sodium level loss
2. Extracellular fluid has a higher concentration than intracellular fluid as a result
3. Fluid flows from intracellular space to the extra cellular spaces

Question 11

What are the symptoms of hypernatremic dehydration?

Answer 11

1. Hyperreflexia // Seizures // Altered consciousness - Water is drawn out of the brain causing cerebral shrinkage.
2. Clinical signs of dehydration are more difficult to recognise e.g. depressed fontanelles due to increased fluid.