Ketoacidosis Flashcards
What is ketogenesis and when does it occur?
Liver converts fatty acids to ketones.
When insufficient supply of glucose and glycogen stores are exhausted eg prolonged fasting or very low carb diets.
What are properties of ketones
Water-soluble fatty acids, can be used as fuel.
Can cross BBB and be used by the brain.
What is a characteristic trait of someone in ketosis?
Acetone smell to breath
How can ketone levels be measured?
In urine - dipstick
In blood - using a ketone meter
In normal patients, the ketone acids are buffered by _____ produced by the kidney, so the blood doesn’t become ____
bicarbonate, acidotic
Why can type 1 diabetes cause hyperglycaemic ketosis resulting in metabolic acidosis.
Lack of insulin so glucose can’t enter body cells. Therefore hyperglycaemia.
Body cells think there is not glucose so stimulates breakdown of glycogen stores.
Body cells still think there is no fuel, so ketogenesis occurs.
Insulin is needed for uptake and utilisation of ketones too.
The ketone acids use up the buffering bicarbonate.
Ketones accumulate in blood causing metabolic acidosis.
This is called diabetic ketoacidosis.
Why would diabetic ketoacidosis occur in a diagnosed T1DM patient with insulin?
Not taking insulin or dose too low.
have underlying infection or illness
How does hyperglycaemia affect the water balance?
Too much glucose overwhelms the kidneys and glucose is filtered through into the urine.
The glucose in the urine draws water out (osmotic diuresis) so patient urinates a lot (polyuria).
Results in severe dehydration.
Stimulates the thirst centre to become thirsty (polydipsia).
How does insulin normally affect potassium levels?
Insulin normally drives potassium into body cells
What happens to potassium levels in diabetic ketoacidosis?
Without insulin, potassium not shifted into body cells. Kidney tries to balance potassium levels by excreting some in urine.
So serum potassium can be normal or high.
However, total body potassium is low because no potassium is stored in the cells.
What can happen to potassium levels when insulin treatment started in T1 DM patients?
Can develop severe serum hypokalaemia (any potassium available in blood is taken up into cells).
This can cause fatal arrhythmias
What are the most dangerous aspects of diabetic ketoacidosis?
Dehydration
Potassium imbalance
Acidosis
How do you treat DKA?
ABCDE
Priority is fluid resuscitation (for dehydration, electrolyte imbalance and acidosis) followed by insulin infusion
Children with DKA are at a high risk of what?
Cerebral oedema
Why can a cerebral oedema occur in children with DKA?
Dehydration and hyperglycaemia can cause water to move from the intracellular space in the brain to the extracellular space, causing brain cells to shrink and become dehydrated.
When given fluids and insulin, water shifts from extracellular space back to intracellular space. Can cause brain cells to swell and become oedematous.
Can lead to brain cell destruction and death.
