Diabetic ketoacidosis

Question 1

What is the definition of diabetic ketoacidosis?

Answer 1

A complication of diabetes mellitus caused by absolute or relative insulin deficiency

Question 2

What are the 3 criteria that need to be met for diagnosing diabetic ketoacidosis?

Answer 2

1. Hyperglycaemia >11 mM or known diabetes
2. Ketonaemia >3 mM or ketonuria >2+
3. Acidosis pH <7.3 and/or bicarbonate <15 mM

Question 3

Does it usually occur in type 1 or type 2 diabetics?

Answer 3

Type 1

Question 4

What are type 2 diabetics with diabetic ketoacidosis more likely to suffer from?

Answer 4

related condition hyperglycaemic hyperosmolar state (HHS)

Question 5

What is the epidemiology of DKA?

Answer 5

Annual incidence of 1-5% amongst patients with type 1 DM
More common in women than men

Question 6

What are 2 causes of diabetic ketoacidosis?

Answer 6

1. Lack of compliance with insulin therapy
2. Acute illness (eg infection, MI, trauma)

Question 7

What is the pathophysiology of DKA?

Answer 7

1. Insulin deficiency renders cells unable to take up and metabolise glucose
2. Glucose remains trapped in the blood from where it is filtered by the kidney in concentrations that exceed renal reabsorption capacity
3. Glycosuria causes a profound osmotic diuresis leading to severe hydration
4. Unable to rely on carbohydrate metabolism, cells switch to fat metabolism and oxidise fatty acids to release acetyl coenzyme A (CoA) in concentrations that saturate the Kreb’s cycle
5. Excess acetyl CoA is converted to the ketone bodies acetone, acetoacetate and beta-hydroxybutyrate, which are released into the blood causing a raised anion gap metabolic acidosis
6. DKA mostly occurs in type 1 DM and is rare in type 2 DM because there is usually adequate levels of insulin to prevent ketogenesis

Question 8

What are the symptoms of DKA?

Answer 8

Polyuria
Polydipsia
Light-headedness
Nausea and vomiting
Abdominal pain
Dyspnoea
Drowsiness
Loss of consciousness
Lack of compliance with insulin therapy
Symptoms of the precipitantc

Question 9

Airway: DKA

Answer 9

May be compromised due to conscious level

Question 10

Breathing: DKA

Answer 10

Kussmaul’s breathing - Hyperventilation to compensate for metabolic acidosis manifesting as ‘air hunger’

Acetone-smelling breath

Question 11

Circulation: DKA

Answer 11

1. Cold pale peripheries
2. Prolonged cap refill times
3. Decreased skin turgor
4. Reduced JVP
5. Sunken eyes
6. Dry lips, mouth and tongue
7. Tachycardia
8. Postural hypertension
9. Absolute hypotension
10. Cardiac arrythmias precipitated by electrolyte disturbances

Question 12

Disability: DKA

Answer 12

1. Confusion
2. Reduced conscious levels

Question 13

Exposure: DKA

Answer 13

Signs of the precipitant

Question 14

What are some differential diagnoses of DKA?

Answer 14

Hyperglycaemic hyperosmolar state (HHS)

Any cause of an acute abdomen (including medical causes) if presenting with abdominal pain

Other cause of raised anion gap metabolic acidosis
Alcohol
‘MUDPILES’: Methanol, uraemia, [DKA], paraldehyde, isoniazid, lactate, ethylene glycol, salicylates
Carbon monoxide/cyanide

Question 15

What investigations can be carried out to investigate DKA?

Answer 15

Capillary blood glucose
Capillary blood ketones
VBG
Full bloods
Blood cultures
ECG
Urinalysis
Chest X-ray

Question 16

What is the initial management of DKA?

Answer 16

Deliver high flow oxygen 15L/min via reservoir mask and titrate to achieve oxygen saturations (SpO2) 94-98% or 88-92% if known to have COPD

Question 17

What should be requested ASAP?

Answer 17

ECG - 12 lead
Chest X-ray
Bloods

Question 18

What should be be the next step after high flow oxygen?

Answer 18

Fluid resuscitation

Question 19

What volume of fluids should be given?

Answer 19

If systolic blood pressure (SBP) <90 mmHg, give 0.9% saline 500 ml IV stat and repeat as necessary until SBP >90 mmHg
If SBP >90 mmHg, give
0.9% saline 1 L IV over 1 hour
0.9% saline 1 L IV over 2 hours
0.9% saline 1 L IV over 2 hours
0.9% saline 1 L IV over 4 hours
0.9% saline 1 L IV over 4 hours
0.9% saline 1 L IV over 6 hours

Question 20

What should be infused?

Answer 20

Insulin infusion

Ask the nursing staff to draw up 50 units of actrapid in 50 ml of 0.9% saline (1 unit/ml) and run at 0.1 unit/kg/hour eg 7 units/hour for a 70 kg individual

Question 21

How quickly should ketone levels fall after insulin infusion?

Answer 21

Ketone levels should fall by 0.5 mM/hour

Question 22

What should be done if ketones do not fall adequately after insulin infusion?

Answer 22

increase the infusion rate by 0.1 unit/hour increments until this target rate is achieved

Question 23

What issues present when rates adequate to switch off ketogenesis are met?

Answer 23

ates adequate to switch off ketogenesis will usually render individuals hypoglycaemic so commence glucose 10% IV at 125 ml/hour once glucose <14 mM
Continue any long-acting insulin therapy at the usual dose and timing

Question 24

What will happen to potassium levels once insulin infusion has been given?

Answer 24

Although potassium levels may be high on arrival, they will fall rapidly once the fixed rate insulin IV infusion commences. The supplementation suggested below should be added to the resuscitation fluid.
Potassium >5.5 mM requires no supplementation
Potassium 3.5-5.5 mM requires supplementation of replacement fluid with potassium chloride (KCl) 40 mM
Potassium <3.5 mM requires supplementation of replacement fluid with KCl 60-80 mM and high dependency unit (HDU) care

Question 25

Should anticoagulation be given?

Answer 25

Yes DKA is a hypercoagulable state so consider enoxaparin 1.5 mg/kg subcutaneously (SC)

Question 26

How often should tests be repeated?

Answer 26

Blood glucose and ketones should be checked hourly VBG should be repeated at 1 hour, and 2 hourly thereafter Aim for a urine output of >0.5 ml/kg/hour; insert a urethral catheter if necessary

Question 27

What clinical features in patients with DKA might you want to consider for a critical care referral?

Answer 27

Hypoxia Hypotension Reduced conscious level Age >65 years Significant cardiac or renal co-morbidities

Question 28

What biochemical features in patients with DKA might you want to consider for a critical care referral?

Answer 28

pH <7.1 Bicarbonate <5 mM Ketonaemia >6 mM Serum osmolalaity >320 mOsm/L Potassium < 3.5 mM on admission

Question 29

What are 6 complications for DKA?

Answer 29

1. Hyperkalaemia 2. Hypokalaemia 3. Hypoglycaemia from fixed rate insulin IV infusion without glucose supplementation 4. Cerebral oedema 5. Pulmonary oedema 6. Death

Question 30

What molecule buffers ketones in the blood?

Answer 30

bicarbonate (produced by the kidneys)

Question 31

Summarise the management for diabetic ketoacidosis:

Answer 31

1) correct dehydration over 48 hours to dilute the hyperglycaemia and ketones 2) insulin infusion 3) once glucose falls to 14mmol/L, give IV dextrose to prevent hypoglycaemia

Question 32

What is a key complication in diabetic ketoacidosis treatment in children?

Answer 32

cerebral oedema

Question 33

Describe how cerebral oedema can manifest in children during treatment of diabetic ketoacidosis:

Answer 33

1) dehydration and hyperglycaemia cause water to move from the intracellular space in the brain to the extracellular space, causing brain cell to shrink 2) rapid correction of dehydration and hyperglycaemia causes a rapid shift in water from the extracellular to intracellular space which can cause the brain to swell and become oedematous 3) this can lead to brain cell destruction and death