Nutrition 1: Fluid and electrolyte imbalance Flashcards
What qualifies as hypernatraemia
Na+ levels above normal range of 133-146mmol/L
Hypernatraemia symptoms
- convulsions
- hypovalaemia
- thirst
- dehydration
- oliguria (low urinary output)
- postural hypotension
- tachycardia
Drugs causing hypernatraemia
- 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
Hyponatraemia
Na+ levels below normal range of 133-146mmol/L
Hyponatraemia symptoms
- drowsiness
- confusion
- nausea
- vomiting
- headache
- cramps
Drugs causing hyponatraemia
- antidepressants
- loop and thiazide diuretics
- carbamazepine
- desmopressin
Hyponatraemia treatment
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
Rehydration treatment
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
Metabolic acidosis (hyperchloraemia)
When chloride levels are above the normal range (103mmol/L)
(metabolic acidosis) hyperchloraemia
Counteracted by sodium bicarbonate which is alkaline.
HyPOkalaemia and HyERchloraemia often occur together. If hyPOkalaemia is present, potassium bicarbonate is preferred
HyPERcaclaemia and HyPERcalciuria
When calcium levels are above the normal range: 2.10 -2.58mmol/L
Hypercaciuria is high levels of calcium in the urine
Hypercalcaemia treatment
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
Drugs which cause hypercalcaemia
Thiazide diuretics
Vitamin D supplements
Hypocalcaemia
range
When calcium levels are below the normal range: 2.10 -2.58mmol/L
Hypocalcaemia treatment
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
Hypomagnesaemia
Magnesium levels below the normal range of 0.7-1.05mmol/L
Hypomagnesaemia treatment
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
Hypomagnesaemia risk factors
alcoholics
Hypomagnesaemia also leads to low Ca2+, K+ and Na+
Phosphate normal range
0.85-1.45mmol/L
HyPERphosphataemia treatment
Phosphate binding agents
HyPOphosphataemia treatment
Phosphate supplements
(IV if moderate -severe)
Normal potassium range
3.5 - 5.3 mmol/L
Hyperkalaemia symptoms
Can cause ventricular fibrillation and cardiac arrest
Drugs that cause hyerkalaemia
HADBEANS
H - Heparin
A -ACE inhibitors/ARBS
D - digoxin
B - beta blockers
E - eplernone (aldosterone antagonist)
A - Amiloride
N-NSAIDs
S- spiranolactone (aldosterone antagonist)
Hyperkalaemia treatment
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
HyPOkalaemia symptoms and causative drugs
Arrhythmias
Muscle hypotonia
Dare insult Betty’s Tough Carpet
- Loop and thiazide Diuretics
- Insulin
- B2 agonist
- Theophylline
- Corticosteroid
Hypokalaemia also predisposes to digoxin toxicity
Hypokalaemia treatment
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
