Electrolyte Imbalances

Question 1

What to give with hyperkalaemia + tall tented T waves?

Answer 1

Calcium gluconate to stabilise myocardium
Salbutamol 5mg neb
Insulin dextrose (10 units in 50ml 50% dextrose) IV over 20mins
Haemodialysis if not responding

Question 2

ECG signs of hyperkalaemia

Answer 2

Flattened P waves 
Broad bizarre QRS
Sloping ST
Tented T waves 
Sine wave ECG

Question 3

Causes of hypoglycaemia in non-diabetics

Answer 3

EXPLAINS H
Exogenous drugs (BB, hypoglycaemics, valproate, salicylate) 
Pituitary insufficiency 
Post prandial – after GI surgery 
Liver disease 
Addisons 
Islet cell tumours  + infection 
Non pancreatic neoplasms  - SCC producing IGF-2 
Starvation 
Hypothyroidism

Question 4

What causes hypercalcaemia?

Answer 4

Hyperparathyroidism
Malignancy
Sarcoidosis

Question 5

What are the S+S of hypercalcaemia?

Answer 5

Confusion, weakness, abdo pain, hypotension, arrhythmias

Question 6

What ECG changes occur with hypercalcaemia?

Answer 6

Short QT, prolonged QRS, flat T waves, AV block

Question 7

How do you treat hypercalcaemia?

Answer 7

IV fluids, furosemide, hydrocortisone, bisphosphonates

Question 8

What causes hypocalcaemia?

Answer 8

CKD, pancreatitis, rhabdomyolysis, tumour lysis syndrome

Question 9

What are the S+S of hypocalcaemia?

Answer 9

Paraesthesia, tetany, seizures, AV block

Question 10

What ECG changes occur with hypocalcaemia?

Answer 10

Long QT, T wave inversion, heart block

Question 11

How do you treat hypocalcaemia?

Answer 11

Treat with calcium chloride + magnesium sulphate

Question 12

What causes hypermagnesemia?

Answer 12

CKD

Question 13

What are the S+S of hypermagnesemia?

Answer 13

Confusion, weakness, resp depression, AV block

Question 14

What are the ECG changes with hypermagnesemia?

Answer 14

Prolonged PR + QT, T wave peak, AV block

Question 15

How do you treat hypermagnesemia?

Answer 15

Calcium chloride + resp support

Question 16

What causes hypomagnesemia?

Answer 16

GI loss, polyuria, alcoholism

Question 17

What are the S+S of hypomagnesemia?

Answer 17

Tremor, ataxia, nystagmus, seizures, arrhythmia

Question 18

What are the ECG changes with hypomagnesemia?

Answer 18

Prolonged PR + QT, ST depression, T wave inversion, flat P waves, long QRS, torsades de pointes

Question 19

Causes of hyperkalaemia

Answer 19

CKD, drugs, rhabdomyolysis, metabolic acidosis, infection

Question 20

S+S of hyperkalaemia

Answer 20

Asymptomatic, weakness, flaccid paralysis, arrhythmias

Question 21

ECG changes with hyperkalaemia

Answer 21

Prolonged PR, flat P waves, tented Tt waves, ST depression, sine waves, wide QRS, bradycardia, AV block

Question 22

Causes of hypokalaemia

Answer 22

GI + renal loss, Cushings, metabolic alkalosis, low magnesium

Question 23

ECG changes with hypokalaemia

Answer 23

U waves, flat T waves, ST changes, arrhythmias

Question 24

S+S of hypokalaemia

Answer 24

Fatigue, weakness, cramps, rhabdomyolysis, ascending paralysis

Question 25

Causes of metabolic alkalosis

Answer 25

Addition of base Chloride depletion (diuretics, D+V) Laxative abuse Potassium depletion (hyperaldosteronism, Cushings)

Question 26

Causes of resp alkalosis

Answer 26

Stimulated resp drive Pneumonia PE Asthma

Question 27

Causes of resp acidosis

Answer 27

Decreased resp drive or chest wall movement | COPD

Question 28

Causes of metabolic alkalosis: addition of base to ECF

Answer 28

Milk-alkali syndrome Excessive NaHCO3 intake Recovery phase from acidosis Massive blood transfusion

Question 29

Causes of metabolic alkalosis: chloride depletion

Answer 29

Loss of gastric acid Diuretics Post-hypercapnia Excess faecal loss

Question 30

Causes of metabolic alkalosis: potassium depletion

Answer 30

Hyperaldosteronism Cushings Excess liquorice Bartter's syndrome

Question 31

Causes of respiratory alkalosis: stimulated respiratory drive

Answer 31

``` CNS = CVA, ICH Hypermetabolic = hyperthyroidism, pregnancy, sepsis, anxiety, hyperthermia, aspirin OD, progesterone, liver failure ```

Question 32

Causes of respiratory alkalosis: hypoxaemia induced

Answer 32

Pneumonia, PE, asthma Congenital heart disease Altitude compensation Metabolic acidosis compensation

Question 33

Causes of respiratory acidosis: decreased respiratory drive

Answer 33

CVA, tumour, encephalitis, haemorrhage | Narcotics + sedatives

Question 34

Causes of respiratory acidosis: decreased chest wall movement

Answer 34

NM disorders, myasthenia gravis, GB Muscle relaxants Trauma, chest wall deformity Tension pneumothorax, airway obstructive

Question 35

Causes of respiratory acidosis: obstructive pulmonary disease

Answer 35

COPD, asthma

Question 36

Normal anion gap metabolic acidosis causes

Answer 36

``` USED CARP Ureteric diversion Small bowel fistula Extra chloride (fluids) DKA Carbonic anhydrase inhibitors Addisons Renal tubular acidosis Pancreatic fistula ```

Question 37

Increased anion gap metabolic acidosis causes

Answer 37

``` MURKLE SEPTIC Methanol, metformin Uraemia Renal failure Ketoacidosis Lactic acidosis Ethanol Salicylates Ethylene glycol Paraldehyde Toluene Iron Cyanide + CO ```

Question 38

Low anion gap causes of metabolic acidosis: Increase in unmeasured cations

Answer 38

``` Lithium toxicity Hypercalcaemia Hypermagnesaemia Hyperkalaemia IgG (multiple myeloma) ```

Question 39

Low anion gap causes of metabolic acidosis: decreased unmeasured anions

Answer 39

Hypoalbuminaemia | Hypophosphatemia

Question 40

Low anion gap causes of metabolic acidosis: chloride over-estimation

Answer 40

Increased chloride Iodide toxicity Hypercholesterolemia

Question 41

How does hyperkalaemia affect the heart?

Answer 41

Suppresses SAN impulse generation + reduces conduction by AVN + Purkinje fibres Causes bradycardia = conduction blocks = arrest

Question 42

What is the order of ECG changes that occur with increasing K?

Answer 42

``` Peaked T waves P wave widens + flattens PR prolongation P waves disappear Broad QRS Sine wave appearance VF ```

Question 43

Management of hyperkalaemia

Answer 43

10% calcium gluconate 10ml over 10 mins 50% glucose 50ml IV with 10 units Actrapid over 10 mins 4mg salbutamol nebs back to back 15mg calcium resonium PO QDS