Diabetic ketoacidosis

Question 1

What is DKA?

Answer 1

Disordered metabolic state that usually occurs in the context of an absolute or relative insulin deficiency accompanied by an increase in the counter-regulatory hormones e.g. glucagon, adrenaline, cortisol and growth hormone

Question 2

What type of diabetes is DKA most common in?

Answer 2

Type 1

Question 3

What are some infections that can increase insulin demand, leading to DKA?

Answer 3

Pneumonia
UTIs
Cellulitis

Question 4

What are some inflammatory disorders that can increase insulin demand, leading to DKA?

Answer 4

Pancreatitis
Cholecystitis

Question 5

What are some forms of intoxication that can increase insulin demand, leading to DKA?

Answer 5

Alcohol
Cocaine
Salicylate
Methanol

Question 6

What are some infarction that can increase insulin demand, leading to DKA?

Answer 6

Acute MI
Stroke

Question 7

What are some iatrogenic factors that can increase insulin demand, leading to DKA?

Answer 7

Steroids
Surgery

Question 8

Describe the formation of ketone bodies in DKA?

Answer 8

1. Ketone bodies are formed from acetyl-CoA in the mitochondria (From ß-oxidation of fats)
2. These are useful in energy metabolism, and are usually converted back into acetyl-CoA, which enters the TCA cycle
3. If glycolysis is reduced and glucose limited, the excess acetyl-CoA remains as ketones

Question 9

What is another non-diabetic condition that can lead to ketoacidosis?

Answer 9

Starvation

Question 10

How does starvation cause ketoacidosis?

Answer 10

Oxaloacetate is consumed for gluconeogenesis and when glucose is not avaliable fatty acids are oxidised to provide energy; the excess acetyl-CoA will be converted into ketones

Question 11

What are some of the consequences of high ketone levels in the blood?

Answer 11

Acidosis
Osmotic diuresis due to high glucose excretion
Decreased renal function
Coma
Death

Question 12

What are some osmotic related symptoms of DKA?

Answer 12

• Thirst and polyuria
• Dehydration

Question 13

What are some ketone body related symptoms of DKA?

Answer 13

• Flushed
• Vomiting
• Abdominal pain and tenderness
• Increased respiratory rate
  
  • Kussmaul’s respiration
• Distinctive smell on breath (not present in all individuals)

Question 14

What is meant by Kussmaul’s respiration?

Answer 14

deep, rapid breathing pattern associated with severe metabolic acidosis

Question 15

How do ketone bodies cause nausea and vomiting?

Answer 15

Ketone bodies can stimulate chemotrigger zone receptors in the brain causing nausea and vomiting

Question 16

How do ketone bodies cause acidosis?

Answer 16

Ketone bodies can give off H+ ions, causing acidosis

Question 17

How do ketone bodies cause arrhythmia and ileus (Abdominal pain)?

Answer 17

H+ moves into the ICF, but K+ leaves, causing an increase in K+ in ECF

This can lead to arrhythmia and ileus (Abdominal pain)

Question 18

How do ketone bodies cause increased respiratory rare and fruity breath?

Answer 18

Increased protons stimulates peripheral chemoreceptors located to the certodi and aortic bodies, connected to vagus nerve

This causes increase in respiratory rate to get rid of CO2, causing Kussmaul’s respiration and breathing off of acetone (Fruity breath)

Question 19

What are some conditions associated with DKA?

Answer 19

• Underlying sepsis
• Gastroenteritis

Question 20

What tests are required in diagnosis of DKA?

Answer 20

Ketone measurement
Blood glucose levels
Bicarbonate levels

Question 21

What ketone level provides diagnosis of DKA?

Answer 21

Ketonaemia ≳3 mmol/L, or significant ketouria (≳2 on standard urine stick)

Question 22

What blood glucose level provides diagnosis of DKA?

Answer 22

Blood glucose > 11.0/L or known DM

Question 23

What bicarbonate level provides diagnosis of DKA?

Answer 23

Bicarbonate <15 mmol/L and/or venous pH <7.3

Question 24

What are some other biochemistry signs of DKA?

Answer 24

Potassium >5.5mmol/L
Raised creatinine
Low sodium
Raised amylase
Raised WCC

Question 25

What are the 5 stages of DKA management?

Answer 25

1. Correction of dehydration - IV fluids
2. Correction of hyperglycaemia - IV insulin
3. Electrolyte imbalance
4. Indentification of comorbid precipitating events
5. Very frequent monitoring and observations

Question 26

Why do DKA patients in management require constant potassium level measurement?

Answer 26

Insulin can further decrease K+ levels

Question 27

What is the fluid replacement strategy used in DKA?

Answer 27

• 1000mL NaCl 0.9% in the first hour
• 20000mL NaCl by end of hour 2
• 30000mL NaCl by end of hour 4
• Once blood-glucose concentration falls below 14 mmol/litre, IV glucose 10% should be given in addition to the sodium chloride 0.9% infusion

Question 28

What is the electrolyte replacement strategy used in DKA?

Answer 28

• NaCl 0.9% as above
• IV Potassium
• Phosphate rarely replaced

Question 29

How is acid-base balance restored in DKA management?

Answer 29

Bicarbonate rarely replaced as once the circulating volume is restored the metabolic acidosis is rapidly compensated

Question 30

What is the insulin replacement strategy used in DKA?

Answer 30

• IV insulin 0.1 units/kg per hour to suppress ketogenesis, lower the glucose and correct the electrolyte disturbance
• Continue ‘usual’ SC daily basal insulin
• Continue IV insulin until ketoacidosis has been resolved; to prevent hypoglycaemia give 10% glucose IV alongside the 0.9% NaCl once blood-glucose concentration falls below 14 mmol/L

Question 31

What monitoring is required after DKA management?

Answer 31

• Monitor blood-ketone and blood-glucose concentrations hourly
• Blood gas and electrolytes every 2-4 hours

Question 32

What are some other management strategies used in some DKA cases?

Answer 32

• Seek underlying cause e.g. infection if suspected
• Patient may aspirate vomit so consider NG tube
• Dehydration, increased blood viscosity and coagulability of DKA increase risk of thromboembolism - all patients should receive prophylactic LMWH

Question 33

How can recurrence of DKA be prevented?

Answer 33

• Education and support before discharge
• Provide patient with ketone meter
• Arrange DSN follow-up and inform GP

Question 34

What are some possible complications of DKA?

Answer 34

• Cerebral oedema - mostly happens in children/YAs
• Hypokalaemia can cause cardiac arrest and paralytic ileus
• Aspiration pneumonia
• ARDS