Electrolyte Abnormalities

Question 1

What is the definition of hyponatremia?

Answer 1

Sodium <135

Question 2

What are the symptoms and signs of hyponatremia?

Answer 2

Symptoms - none, headache, lethargy, nausea, vomiting, muscle cramps
Signs - disorientation, seizures, coma, death

Question 3

What are the categories of causes of hyponatremia?

Answer 3

• Pseudohyponatremia
• Sodium depletion
• Excess water intake
• Reduced renal free water clearance

Question 4

What causes pseudohyponatremia?

Answer 4

• Hyperglycaemia
• Hypertriglycerdiaemia
• Non-physiological osmolyte

If you correct these, the hyponatremia will correct itself

Question 5

What causes sodium depletion?

Answer 5

Renal loss - diuretics, salt wasting, nephropathy

Extra renal loss - gut loss (vomiting)

Question 6

What causes excess water intake?

Answer 6

• Diabetes insipidus

- IV therapy

Question 7

What causes reduced renal free water clearance?

Answer 7

• Hypovolaemia
• Cardiac failure
• Nephrotic syndrome
• Hypothyroidism
• Hypoadrenalism
• SIADH

Question 8

How should hyponatremia be managed?

Answer 8

• Fluid restriction
• Sodium replacement with hypertonic saline at a rate of 10mmol/L/24h

RISK OF CEREBRAL OEDEMA AND OSMOTIC DEMYELINATION SYNDROME DEATH IF THIS ISNT DONE WELL

Question 9

What is hypernatremia?

Answer 9

Sodium > 144mmol/L

Question 10

What are the signs and symptoms of hypernatremia?

Answer 10

Signs - Twitching, spasms, coma, death

Symptoms - THIRST, nausea, loss of appetite, confusion, weakness

Question 11

What are the causes of hypernatremia?

Answer 11

• Dehydration (elderly, terminal ilness)

- Excess sodium in IV therapy

Question 12

What is hypokalemia?

Answer 12

Potassium < 3.5

Question 13

What are the signs and symptoms of hypokalemia?

Answer 13

Signs - ARRHYTHMIAS, paralysis

Symptoms - ASYMPTOMATIC, nausea, fatigue, weakness, constipation, cramping, palpitations

Question 14

What are the complications of hypokalemia?

Answer 14

Cardio -arrhythmias
Neuromuscular - tetany, paralysis, rhabdomyolysis
Renal - decreased GFR, nephritis, metabolic alkalosis
Endocrine - growth retardation, decreased insulin secretion

Question 15

What is hyperkalaemia?

Answer 15

Potassium < 5.0

Question 16

What are the signs and symptoms of hyperkalemia?

Answer 16

SIGNS - ARRHYTHMIAS, paralysis

SYMPTOMS - weakness, parasthesia, paralysis

Question 17

What are the complications of hyperkalemia?

Answer 17

Cardio - arrhythmias
Neuromuscular - parasthesia, weakness
Renal - decreased renal NH4 production
Endocrine - increased insulin secretion

Question 18

What are the ECG features of hypokalemia?

Answer 18

• ST depression
• T wave flattening and inversion
• Prominent U waves

Question 19

What are the ECG features of hyperkalemia?

Answer 19

• Tented T waves

Question 20

What causes hypokalemia?

Answer 20

GI - deficiecnt intake, GI losses
Renal - metabolic alkalosis, diuretics, tubular disorders, magnesium depletion
Cell shifts without depletion

Question 21

How is hypokalemia managed?

Answer 21

Oral replacement with Sando K tablets if mild/moderate

IV Kcl with 0.9% saline if severe

Question 22

What causes hyperkalemia?

Answer 22

Decreased excretion - drugs, renal failure, addison, acidosis
Increased release from cells - acidosis, tissue damage (rhabdomyolysis), digoxin
Increased extraneous load - potassium chloride, salt substitutes, blood transfusion

Question 23

How is hyperkalemia managed?

Answer 23

1. Stabilise myocardium with calcium gluconate
2. IV insulin and dextrose
3. Salbutamol nebulisers
4. Dialysis if no response

DO ECG!!!!