Nutrition 1: Fluid and electrolyte imbalance

Question 1

What qualifies as hypernatraemia

Answer 1

Na+ levels above normal range of 133-146mmol/L

Question 2

Hypernatraemia symptoms

Answer 2

• convulsions
• hypovalaemia
• thirst
• dehydration
• oliguria (low urinary output)
• postural hypotension
• tachycardia

Question 3

Drugs causing hypernatraemia

Answer 3

• oral contraceptives
• corticosteroids
• sodium bicarbonate
• sodium content in IV antibiotics
• lithium

if hypernatraemia is caused by volume depletion, such as diabetes insipidus, IV glucose can be administered

Question 4

Hyponatraemia

Answer 4

Na+ levels below normal range of 133-146mmol/L

Question 5

Hyponatraemia symptoms

Answer 5

• drowsiness
• confusion
• nausea
• vomiting
• headache
• cramps

Question 6

Drugs causing hyponatraemia

Answer 6

• antidepressants
• loop and thiazide diuretics
• carbamazepine
• desmopressin

Question 7

Hyponatraemia treatment

Answer 7

Mild-moderate:
* oral sodium chloride or sodium bicarbonate (if patient’s blood pH is too low/acidic sodium bicarbonate would be preferred)

Severe:
* IV saline
if saline is isotonic must be given by peripheral vein
if saline is more concentrated must be given by central vein.
Saline must be given slowly due to risk of osmotic demyelination of neurones

Question 8

Rehydration treatment

Answer 8

If electrolyte imbalance imbalance is present:
oral rehydration therapy (K+, Na+, Glucose) should be given:
* Over 3-4 hours in diarrhoea
* Over 12 hours if hypovalaemia is caused by hyernatraemic dehydration, e.g in diabetes insipidus where a lot of water is lost in urine

To replace water deficit:
IV glucose can be adminstered to place deficit HOWEVER should not be given alone unless there is no signficant loss of electrolytes, e.g hypercalcaemia, diabetes insipidus

Question 9

Metabolic acidosis (hyperchloraemia)

Answer 9

When chloride levels are above the normal range (103mmol/L)

Question 10

(metabolic acidosis) hyperchloraemia

Answer 10

Counteracted by sodium bicarbonate which is alkaline.

HyPOkalaemia and HyERchloraemia often occur together. If hyPOkalaemia is present, potassium bicarbonate is preferred

Question 11

HyPERcaclaemia and HyPERcalciuria

Answer 11

When calcium levels are above the normal range: 2.10 -2.58mmol/L

Hypercaciuria is high levels of calcium in the urine

Question 12

Hypercalcaemia treatment

Answer 12

Hypercalcaemia treatment:
* Bisphosphonates
* Corticosteroids

Bisphosphonates and corticosteroids reduce serum calcium. Bisphosphonates cause hypocalcaemia through slowing down bone resorption, by slowing down osteoclasts

Hypercalcaemia associated with malignany treatment:
* Calcitonin

Hypercalcaemia caused by hyperparathyroidism (high levels of parathyroid hormone):
* Cinaclet; reduced parathyroid hormone therefore calcium
* Paracalcitol; used in secondary parathyroidism caused by chonic renal failure

Hypercalciuria
* Bendroflumethiazide + increase fluid intake + reduce dietary calcium

osteoclasts release calcium from bone into serum

Question 13

Drugs which cause hypercalcaemia

Answer 13

Thiazide diuretics
Vitamin D supplements

Question 14

Hypocalcaemia

range

Answer 14

When calcium levels are below the normal range: 2.10 -2.58mmol/L

Question 15

Hypocalcaemia treatment

Answer 15

Can cause osteoperosis

Mild-moderate hypocalcaemia:
vitamin D and calcium supplements

Severe acute hypocalcaemia or hypoca;caemic tetany (muslce spasms):
Slow IV calcium gluconate *too fast = arrhythmias

Question 16

Hypomagnesaemia

Answer 16

Magnesium levels below the normal range of 0.7-1.05mmol/L

Question 17

Hypomagnesaemia treatment

Answer 17

Magnesium is released in large amounts in gastrointestinal fluid, so a loss of magneisum will be observed after dirarrhoea, stoma or fistula.

Treatment:
IV/IM magnesium sulphate
- IM can be painful
- IV also used to treat arrhythmias and used in pregnancy

Question 18

Hypomagnesaemia risk factors

Answer 18

alcoholics

Hypomagnesaemia also leads to low Ca2+, K+ and Na+

Question 19

Phosphate normal range

Answer 19

0.85-1.45mmol/L

Question 20

HyPERphosphataemia treatment

Answer 20

Phosphate binding agents

Question 21

HyPOphosphataemia treatment

Answer 21

Phosphate supplements
(IV if moderate -severe)

Question 22

Normal potassium range

Answer 22

3.5 - 5.3 mmol/L

Question 23

Hyperkalaemia symptoms

Answer 23

Can cause ventricular fibrillation and cardiac arrest

Question 24

Drugs that cause hyerkalaemia

Answer 24

HADBEANS

H - Heparin
A -ACE inhibitors/ARBS
D - digoxin
B - beta blockers
E - eplernone (aldosterone antagonist)
A - Amiloride
N-NSAIDs
S- spiranolactone (aldosterone antagonist)

Question 25

Hyperkalaemia treatment

Answer 25

Mild to moderate with no ECG changes:
Calcium resonium

Acute, severe hyperkalaemia which is potassium levels > 6.5mmol/L:
Slow IV calcium gluconate

IV insulin, glucose and salbutamol all cause Hypokalaemia so it can also be given to further reduce potassium levels

Hyperkalaemia usually occurs with association to hyperchloraemia (acidosis). Sodium bicarbonate is given to combat this.
BUT sodium bicarbonate should not be given through the same line as sodium gluconate = prescripitation and thus THROMBOSIS

Question 26

HyPOkalaemia symptoms and causative drugs

Answer 26

Arrhythmias
Muscle hypotonia

Dare insult Betty’s Tough Carpet

• Loop and thiazide Diuretics
• Insulin
• B2 agonist
• Theophylline
• Corticosteroid

Hypokalaemia also predisposes to digoxin toxicity

Question 27

Hypokalaemia treatment

Answer 27

Mild Hypokalaemia:
* Low potassium is linked to low chloride, so oral slow potassium chloride is preferred treatment option
* Smaller doses must be given in renal impairement

Potassium salts cause nausea and vomiting –> poor compliance. Potassium-sparing diuretic may be given instead (if hypokalaemia is caused by loop/thiazide diuretic).

Severe hypokalaemia
* IV potassium chloride given (glucose should not be given for potassium repelacement as it causes hypokalaemia).
Potassium chloride overdoses is FATAl, ready mixed solutions should be used or thoroughly mix concentrate