Diabetic Ketoacidosis

Question 1

What is the definition of diabetic ketoacidosis? [2]

Answer 1

a serious complication of (type 1) diabetes mellitus / in which there is a combination of hyperglycaemia and severe acidosis (due to large numbers of ketones in the blood)

Question 2

What is the mechanism of ketoacidosis? [3]

Answer 2

1. ketoacidosis is an alternative metabolic pathway of energy production, used in starvation states
2. when there is excessive glucose but insufficient insulin, ketoacidosis is the only mechanism of energy production
3. increased production of acetyl-CoA and ketone bodies

Question 3

What is the aetiology of diabetic ketoacidosis? [5]

Answer 3

1. hallmark of T1DM, usually seen in -
2. previously undiagnosed diabetes
3. interruption of insulin therapy
4. stress of intercurrent illness
5. most common error is for patients to reduce or omit insulin when they feel they are unable to eat - insulin may be adjusted but should never be stopped

Question 4

What are the risk factors for diabetic ketoacidosis? SISMIUP [6]

Answer 4

1. stopping insulin therapy
2. infection
3. surgery
4. myocardial infarction
5. undiagnosed diabetes
6. pancreatitis

Question 5

What is the pathophysiology of diabetic ketoacidosis? [6]

Answer 5

1. ketoacidosis is a state of uncontrolled catabolism due to insulin deficiency
2. in the absence of insulin there is increased hepatic gluconeogenesis and decreased peripheral uptake of glucose by muscle and fat tissue
3. high blood glucose results in osmotic diuresis and dehydration and loss of electrolytes
4. peripheral lipolysis results in increased circulating free fatty acids which are broken down to acetyl-CoA and converted to ketone bodies
5. accumulation of ketone bodies results in metabolic acidosis
6. progressive dehydration impairs renal excretion of H+ ions and ketones, further aggravating acidosis

Question 6

What are the clinical presentations of diabetic ketoacidosis? [7]

Answer 6

1. ketotic breath - smelling of pear drops
2. gradual drowsiness
3. dehydration
4. vomiting
5. Kussmaul’s hyperventilation - deep rapid breathing
6. abdominal pain
7. polyuria and polydipsia

Question 7

How is diabetic ketoacidosis diagnosed? [6]

Answer 7

1. acidaemia - blood pH <7.3 or HCO3(-) <15.0mmol/L
2. hyperglycaemia - blood glucose >11.0mmol/L or known diabetes mellitus
3. ketonaemia - >3.0mmol/L or significant ketonuria
4. ECG and cardiac enzymes - check for myocardial infarction
5. CXR and urine - look for infection
6. U&E - look for dehydration

Question 8

What is the treatment for diabetic ketoacidosis? [4]

Answer 8

1. immediate ABC management
2. replace fluid loss with IV 0.9% saline
3. restore electrolyte loss (K+)
4. replace deficient insulin - give insulin + glucose to prevent hypoglycaemia