Diabetic Ketoacidosis

Question 1

What is the mechanism of ketoacidosis?

Answer 1

Normally, the body metabolises carbohydrates, leading to efficient energy production. Ketoacidosis is an alternative metabolic pathway used in starvation states, which is far less efficient, and produces acetone as a byproduct.

Question 2

What happens in acute ketoacidosis?

Answer 2

There is excessive glucose, but because of a lack of insulin, this cannot be taken up into cells to be metabolised, pushing the body into a starvation-like state where ketoacidosis is the only mechanism of energy production.

Question 3

Why is acute ketoacidosis medically important?

Answer 3

The combination of severe acidosis and hyperglycaemia can be deadly, and so early recognition and treatment is important

Question 4

What is the typical presentation of diabetic ketoacidosis?

Answer 4

• Gradual drowsiness
• Vomiting
• Dehydration

Question 5

What patients should you measure glucose in?

Answer 5

All those with;

• Unexplained vomiting
• Abdominal pain
• Polyuria
• Polydipsia
• Lethargy
• Anorexia
• Ketotic breath
• Dehydration
• Coma
• Deep breathing

Question 6

What are the triggers for diabetic ketoacidosis?

Answer 6

• Infection
• Surgery
• MI
• Chemotherapy
• Pancreatitis
• Anti-psychotics
• Wrong insulin dose/non-compliance

Question 7

What are the diagnostic criteria for diabetic ketoacidosis?

Answer 7

1. Acidaemia, with a venous blood pH <7.3 or HCO₃^- <15mmol/L
2. Hyperglycaemia, with blood glucose >11mmol/L, or known diabetes mellitus
3. Ketonaemia (>3mmol/L), or significant ketonuria (more than 2+ on dipstick)

Question 8

What investigations should be done in diabetic ketoacidosis?

Answer 8

• ECG
• CXR
• Urine dipstick and MSU
• Capillary and lab glucose
• Blood ketones
• VBG (or ABG if decreased GCS or hypoxia)
• U&E
• Osmolality
• FBC

Question 9

What are the criteria for a severe DKA?

Answer 9

• Blood ketones >6mmol/L
• Venous bicarbonate <5mmol/L
• Venous/arterial pH <7.0
• K <3.5mmol/L on admission
• GCS <12
• Sats <92% on air (assuming no respiratory disease)
• Systolic BP <90mmHg
• Pulse >100 or <60bpm
• Anion gap above 16

Question 10

What should be done if a patient presents with severe DKA?

Answer 10

• Consider transfer to HDU/ITU for monitoring and central venous access
• Get senior help

Question 11

What are the steps in acute management of diabetic ketoacidosis?

Answer 11

1. Insert 2 large-bore cannulae
2. Start fluid 1L 0.9% saline over 2 hour (if systolic BP <90mmHg, give 500ml bolus over 15 mins and reassess. If systolic BP still <90mmHg, give another 500ml bolus and seek senior review. If still <90mmHg, ICU)
3. Venous blood gas for pH and bicarbonate, bedside and lab glucose and ketones, and other tests
4. Insulin