Diabetic ketoacidosis Flashcards
Ketogenesis
Occurs when insufficient supply of glucose and glycogens stores are exhausted
Liver takes fatty acids and converts them to ketones to be used as fuel
Ketoacidosis
When cells have no fuel they initiate process of ketogenesis
Over time glucose and ketone levels get higher and higher
Initially bicarbonate buffers ketone acids to maintain normal pH
Over time ketone acids use up bicarbonate and blood becomes acidic
Dehydration in DKA
Hyperglycaemia overwhelms kidneys and glucose starts being filtered out into urine
Glucose draws water with it by osmotic diuresis
Causes polyuria and polydipsia
Potassium imbalance
Insulin normally drives potassium into cells
Without insulin potassium is not stored in cells so total body potassium is low (serum can be high/normal)
When treatment with insulin starts patients can develop severe hypokalaemia very quickly
Brain in DKA
Dehydration and high blood sugar cause water to move from intracellular space in brain to extracellular
Causes brain cells to shrink and become dehydrated
Risk of rapid correction of dehydration and hyperglycaemia
Shift in water from extracellular space to intracellular space in brain cells
Causes cerebral oedema which can lead to brain cell destruction and death
Neuro obs monitored very closely
Signs of cerebral oedema
Headache
Altered behaviour
Bradycardia
Changes in consciousness
Management of cerebral oedema
Slowing IV fluids
IV mannitol
IV hypertonic saline
Presentation of DKA
Polyuria
Polydipsia
Nausea and vomiting
Weight loss
Acetone smell to their breath
Dehydration and hypotension
Altered consciousness
Symptoms of underlying trigger e.g. sepsis
Diagnosing DKA
Hyperglycaemia- blood glucose >11mmol/L
Ketosis- blood ketones >3mmol/L
Acidosis- pH <7.3
Two pillars of correcting DKA
Correct dehydration evenly over 48 hours
Give fixed rate insulin
Fluid replacement
Most patients deplete 5-8 litres
Isotonic saline used initially even if severely acidotic
Insulin treatment
IV infusion started at 0.1unit/kg/hour
Once blood glucose <15mmol/L an infusion of 5% dextrose should be started
(long acting insulin continued and short acting should be stopped)
Correct electrolyte disturbance
Serum potassium falls quickly following treatment with insulin
May need to add potassium to replacement fluids
If rate of potassium infusion >20mmol/hour then need cardiac monitoring
Correct electrolyte disturbance
Serum potassium falls quickly following treatment with insulin
May need to add potassium to replacement fluids
If rate of potassium infusion >20mmol/hour then need cardiac monitoring
