Diabetic ketoacidosis

Question 1

What is diabetic ketoacidosis?

Answer 1

State of uncontrolled catabolism associated with insulin deficiency

Question 2

Pathophysiology of ketoacidosis

Answer 2

Normal state: body metabolises carbs >> produces energy

Kotacidosis = alternative pathway used in states of starvation > produces acetone as a by-product

Glucose uptake is limited due to lack of insulin >> glucose remains in blood and as a result an osmotic diuresis occurs >> fluid and electrolytes are lost >> dehydration

Rapid lipolysis occurs (fat is the source of energy) this increases circulating free fatty acids which are broken down in the liver into acetyl-coA >> this is then cinverted into ketone bodies

Ketone body accumulation = acidosis >> ketones are lost in the urine and the breath

Respiratory rate increases to try and compensate for the metabolic acidosis by breathing off CO2

As dehydration worsens, the kidneys are less able to excrete ketones and H+ >> acidosis worsens

Acidosis causes increased K+ outside cells >> insulin is needed for Na/K transporter function so this further contributes to hyperkalaemia

Ketone bodies e.g. beta-hydroyxbutyrate = N&V meaning more fluid and electrolytes lost

Question 3

When is ketoacidosis seen?

Answer 3

• Previously undiagnosed T1DM
• Interruption of insulin therapy
• Stress/ illness
• Following surgery
• MI
• Pancreatitis
• Chemo
• Antipsychotics

Question 4

Clinical features of ketoacidosis

Answer 4

• Hyperventilation (trying to correct metabolic acidosis)
• Nausea/ vomiting
• Abdo pain
• Confusion/ stupor (if severe)
• Smell of ketones = instant diagnosis
• Dry skin (dehydration)
• Low temperature

Question 5

Typical presenting feature of DKA

Answer 5

Drowsy, vomiting, dehydrated patient with T1DM

🥱 🤮 💦

Question 6

How is DKA diagnosed?

Answer 6

Demonstration of hyperglycaemia + ketonaemia // heavy ketonuria + acidosis

Three things must be present:

1. Blood glucose >11mmol/L OR known diabetic

**Note a patient with DM may have a lower than expected blood glucose but still be in DKA**

2. Ketones: >3mmol/L or 2++ on dipstick

3. pH: <7.3 on blood gas OR bicarb <15mmol/L

Hyperglycaemia indicated by disptick followed by bloods sent to lab

ABG: shows low CO2, low pH

Bloods: hyponatraemia, hyperkalaemia

Question 7

What is Kussmaul breathing?

Answer 7

🫁 Emergency response to acidosis

Deep, heavy, laboured breathing in an attempt to breathe off some CO2 to correct acidosis

Question 8

What is an anion gap?

Answer 8

The anion gap is the difference between the number of cations versus anions - evaluates states of acidosis

If the gap is greater than normal, then high anion gap metabolic acidosis is diagnosed

Question 9

What is the main electrolyte deranged in DKA?

Answer 9

Potassium

Question 10

Management of DKA

Answer 10

Overall: replace fluid + electrolytes

Refer to local guidelines

Replace fluid: 0.9% saline

• Replace electrolytes: potassium given as soon as insulin given as insulin increased K+ uptake into cells
• Restore acid-base balance: a patient with healthy kidneys, once circulating volume is restored, will correct acidosis meaning bicarbonate is rarely needed (only if pH is <7.0) bicarbonate best given as an isotonic solution (1.26%)
• Replace insulin: short acting insulin given IV if monitoring is possible, if not IM every hour - subcutaneous route is avoided as patients in hypovolemic shock will have poor blood flow
• Seek underlying cause