Electrolyte Imbalance Flashcards

1
Q

What can cause pseudohyperkalaemia?

A

Venepuncture technique.
Thrombocytosis/leucocytosis.
Haemolysis.

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2
Q

What can cause hyperkalaemia?

A
Diet
Medications - beta blockers, digoxin, ACEi, NSAIDsetc. 
Tissue breakdown
Haemolysis
Metabolic acidosis
Hyperosmolality/hyperglycaemia
Insulin deficiency
Hypoaldosteronism
Reduced urinary excretion
Reduced GFR
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3
Q

What value is classed as hyperkalaemia?

A

> 5.5

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4
Q

Name some common medications that can raise potassium.

A
ACEi/ARBs
Spironolactone
Trimethoprim
Beta-blockers
Calcineuric inhibitors
ForteJuice
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5
Q

What are the symptoms of hyperkalaemia?

A
Generalised weakness
Flaccid paralysis
Paraesthesia hands and feet
Lethargy, confusion
Palpitations
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6
Q

What is the treatment of hyperkalaemia?

A
Calcium gluconate
Insulin
Salbutamol
Sodium bicarbonate
Fluids
Loop diuretics
Calcium resonium with laxatives
Dialysis
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7
Q

What are the indications for giving calcium gluconate?

A

Potassium >6

ECG changes present.

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8
Q

What is the management if potassium is between 6 and 6.5 but there are no ECG changes?

A

Give calcium resonium and monitor bloods.

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9
Q

At what value is hypokalaemia present?

A

<3.5

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10
Q

What are the causes of hypokalaemia?

A
Diarrhoea
Diuretics
Hyperaldosteronism
Post-operative
Coronary ischaemia
Critical illness
Re-feeding
Hypomagnesium
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11
Q

What is the presentation of hypokalaemia?

A
Muscle weakness
Arrhythmias
Polyuria
Rhabdomyolysis (rare)
Paralysis (rare)
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12
Q

Which ECG changes can be seen in hypokalaemia?

A

Increased amplitude and width of P wave.
Prolongation of the PR interval.
T wave flattening and inversion.
ST depression
Prominent U waves
Apparent long QT interval due to fusion of T and U waves.

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13
Q

Which kind of arrhythmias can be caused by hypokalaemia?

A
Atrial fibrillation
Atrial flutter
Atrial tachycardia
Ventricular tachycardia
Ventricular fibrillation
Torsades de Pointes
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14
Q

What is the management of hypokalaemia?

A

Replace potassium. Rate of IV infusion should not exceed 10mmol/hour.

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15
Q

At what value is hypercalcaemia?

A

Elevated corrected calcium >2.62

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16
Q

What are the most common causes of hypercalcaemia?

A

Primary hyperparathyroidism.

Malignancy.

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17
Q

What are the causes of hypercalcaemia?

A
Calcium supplementation
Hyperparathyroidism
Iatrogenic, immobilization
Multiple myeloma, milk-alkali syndrome, medication
Parathyroid hyperplasia or adenoma
Alcohol
Neoplasm
Zollinger Ellison syndrome
Excessive vitamin A
Excessive vitamin D
Sarcoidosis
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18
Q

What are the symptoms of hypercalcaemia?

A
"Bones, stones, groans, moans"
Pain - pancreatitis, renal stones, bony pain, abdominal pain
Nausea/vomiting, constipation
Delirium, seizures, coma
Malaise, weakness, anorexia
Polydipsia, polyuria
Cardiac arrhythmias
19
Q

What are the investigations in hypercalcaemia?

A
Adjusted calcium
PTH
Serum electrophoresis
Urinary Bence Jones
TSH
ACE
Serum vitamin D
Urinary calcium
ECG
CXR
20
Q

What is the treatment for hypercalcaemia?

A

IV fluids (0.9% saline) - 1 litre, 8 hourly
Stop precipitants
After 24-48 hours of rehydration consider bisphosphonate.
May require dialysis
Investigate and treat underlying cause.

21
Q

What are the symptoms and signs of hypocalcaemia?

A
Paraesthesia
Tetany
Confusion
Cardiac arrhythmia
Seizure
22
Q

What are the causes of hypocalcaemia?

A

Secondary hyperparathyroidism
Vitamin D deficiency
Resistance to PTH
Hypoparathyroidism

23
Q

Which investigations should be ordered for somebody with hypocalcaemia?

A
Mg
Hb
Vitamin D
PTH
PO4
U&amp;Es
ECG
24
Q

What is the management of hypocalcaemia?

A

Correct hypomagnesaemia first.
Calcium gluconate
Continuous infusion of 40ml in 1 litre 0.9% sodium chloride

25
What are the symptoms of hyponatraemia?
``` Often asymptomatic Gait disturbance Muscle weakness Nausea/vomiting Weakness Disorientation Headache Worsening confusion Impaired consciousness Seizures Coma Death ```
26
What is the management of hyponatraemia?
Hypertonic saline
27
What are the symptoms of hyponatraemia?
Confusion Headache Nausea
28
At what rate should hyponatraemia be corrected?
8-12mmol/24 hours.
29
What are the causes of SIADH?
Drugs Carcinoma Pulmonary disorders Nervous system disorders
30
What happens to osmolality in SIADH?
Serum osmolality <275Osm/kg Urine osmolality >100 Osm/kg Urine sodium concentration >30mmol/l
31
At what value is hypernatraemia?
>145
32
What can cause hypernatraemia?
Decrease in total body water relative to electrolyte content: - iatrogenic water loss - diarrhoea, burns, dehydration, diabetes insipidus - mineralocorticoid exccess
33
What are the symptoms of hypernatraemia?
Thirst | Altered mental state
34
What are the investigations for hypernatraemia?
U&Es Glucose Paired serum and urine osmolalities, urinary Na
35
At what rate should Na be reduced in hypernatraemia?
No more than 10-12mmol/l per day
36
At what value is hypomagnesaemia?
<0.7 mmol/l
37
What are the symptoms of hypomagnesaemia?
``` Confusion, agitation Nausea and vomiting Weakness, tremors Paraesthesia Tetany Seizures Arrhythmia ```
38
What are the causes of hypomagnesaemia?
``` Diarrhoea & vomiting Malabsorption Osmotic diuresis Hyperaldosteronism Drug effects Acute pancreatitis Post DKA Alcoholism Malnutrition ```
39
Which drugs are associated with hypomagnesaemia?
``` Thiazide and loop diuretics Cisplatin Cyclosporin Aminoglycoside antibiotics Focarnet Amhotericin B PPI ```
40
What is the management of hypomagnesaemia has caused Torsades de pontes?
IV bolus mangnesium 2g
41
What is the management of somebody with a hypomagnesaemia of 0.3-0.7mmol/l and is asymptomatic?
Magnesium aspartate/magnesium hydroxide/magnesium glycerophosphate/magnesium oxide Reduce in renal impairment Note oral Mg can cause diarrhoea
42
What is the management of somebody with a hypomagnesaemia of <0.3mmol/l or is symptomatic?
20-30mmol/day up to five days | Add 20 mmol (10ml of magnesium sulphate 50%) to 500ml infusion bag of glucose 5% and infused over 12-24 hours
43
When is hypermagnesaemia seen?
In context of magnesium infusion and renal insufficiency.
44
What are the symptoms of hypermagnesaemia?
``` Flushing Hypotension Diarrhoea Muscle weakness Confusion Coma Cardiac arrhythmias Hypocalcaemia. ```