Electrolyte Imbalances Flashcards
What to give with hyperkalaemia + tall tented T waves?
Calcium gluconate to stabilise myocardium
Salbutamol 5mg neb
Insulin dextrose (10 units in 50ml 50% dextrose) IV over 20mins
Haemodialysis if not responding
ECG signs of hyperkalaemia
Flattened P waves Broad bizarre QRS Sloping ST Tented T waves Sine wave ECG
Causes of hypoglycaemia in non-diabetics
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
What causes hypercalcaemia?
Hyperparathyroidism
Malignancy
Sarcoidosis
What are the S+S of hypercalcaemia?
Confusion, weakness, abdo pain, hypotension, arrhythmias
What ECG changes occur with hypercalcaemia?
Short QT, prolonged QRS, flat T waves, AV block
How do you treat hypercalcaemia?
IV fluids, furosemide, hydrocortisone, bisphosphonates
What causes hypocalcaemia?
CKD, pancreatitis, rhabdomyolysis, tumour lysis syndrome
What are the S+S of hypocalcaemia?
Paraesthesia, tetany, seizures, AV block
What ECG changes occur with hypocalcaemia?
Long QT, T wave inversion, heart block
How do you treat hypocalcaemia?
Treat with calcium chloride + magnesium sulphate
What causes hypermagnesemia?
CKD
What are the S+S of hypermagnesemia?
Confusion, weakness, resp depression, AV block
What are the ECG changes with hypermagnesemia?
Prolonged PR + QT, T wave peak, AV block
How do you treat hypermagnesemia?
Calcium chloride + resp support
What causes hypomagnesemia?
GI loss, polyuria, alcoholism
What are the S+S of hypomagnesemia?
Tremor, ataxia, nystagmus, seizures, arrhythmia
What are the ECG changes with hypomagnesemia?
Prolonged PR + QT, ST depression, T wave inversion, flat P waves, long QRS, torsades de pointes
Causes of hyperkalaemia
CKD, drugs, rhabdomyolysis, metabolic acidosis, infection
S+S of hyperkalaemia
Asymptomatic, weakness, flaccid paralysis, arrhythmias
ECG changes with hyperkalaemia
Prolonged PR, flat P waves, tented Tt waves, ST depression, sine waves, wide QRS, bradycardia, AV block
Causes of hypokalaemia
GI + renal loss, Cushings, metabolic alkalosis, low magnesium
ECG changes with hypokalaemia
U waves, flat T waves, ST changes, arrhythmias
S+S of hypokalaemia
Fatigue, weakness, cramps, rhabdomyolysis, ascending paralysis
Causes of metabolic alkalosis
Addition of base
Chloride depletion (diuretics, D+V)
Laxative abuse
Potassium depletion (hyperaldosteronism, Cushings)
Causes of resp alkalosis
Stimulated resp drive
Pneumonia
PE
Asthma
Causes of resp acidosis
Decreased resp drive or chest wall movement
COPD
Causes of metabolic alkalosis: addition of base to ECF
Milk-alkali syndrome
Excessive NaHCO3 intake
Recovery phase from acidosis
Massive blood transfusion
Causes of metabolic alkalosis: chloride depletion
Loss of gastric acid
Diuretics
Post-hypercapnia
Excess faecal loss
Causes of metabolic alkalosis: potassium depletion
Hyperaldosteronism
Cushings
Excess liquorice
Bartter’s syndrome
Causes of respiratory alkalosis: stimulated respiratory drive
CNS = CVA, ICH Hypermetabolic = hyperthyroidism, pregnancy, sepsis, anxiety, hyperthermia, aspirin OD, progesterone, liver failure
Causes of respiratory alkalosis: hypoxaemia induced
Pneumonia, PE, asthma
Congenital heart disease
Altitude compensation
Metabolic acidosis compensation
Causes of respiratory acidosis: decreased respiratory drive
CVA, tumour, encephalitis, haemorrhage
Narcotics + sedatives
Causes of respiratory acidosis: decreased chest wall movement
NM disorders, myasthenia gravis, GB
Muscle relaxants
Trauma, chest wall deformity
Tension pneumothorax, airway obstructive
Causes of respiratory acidosis: obstructive pulmonary disease
COPD, asthma
Normal anion gap metabolic acidosis causes
USED CARP Ureteric diversion Small bowel fistula Extra chloride (fluids) DKA Carbonic anhydrase inhibitors Addisons Renal tubular acidosis Pancreatic fistula
Increased anion gap metabolic acidosis causes
MURKLE SEPTIC Methanol, metformin Uraemia Renal failure Ketoacidosis Lactic acidosis Ethanol Salicylates Ethylene glycol Paraldehyde Toluene Iron Cyanide + CO
Low anion gap causes of metabolic acidosis: Increase in unmeasured cations
Lithium toxicity Hypercalcaemia Hypermagnesaemia Hyperkalaemia IgG (multiple myeloma)
Low anion gap causes of metabolic acidosis: decreased unmeasured anions
Hypoalbuminaemia
Hypophosphatemia
Low anion gap causes of metabolic acidosis: chloride over-estimation
Increased chloride
Iodide toxicity
Hypercholesterolemia
How does hyperkalaemia affect the heart?
Suppresses SAN impulse generation + reduces conduction by AVN + Purkinje fibres
Causes bradycardia = conduction blocks = arrest
What is the order of ECG changes that occur with increasing K?
Peaked T waves P wave widens + flattens PR prolongation P waves disappear Broad QRS Sine wave appearance VF
Management of hyperkalaemia
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
