Management of Diabetic Emergencies

Question 1

What causes DKA

Answer 1

Starvation in the midst of plenty:
A relative lack of insulin leads to hyperglycaemia as cells are not able to take up glucose
This turns on fatty acid metabolism resulting in the production of acidic ketones

Question 2

How to confirm a diagnosis of DKA

Answer 2

Glucose >11 mmol/L (or known diabetes)
pH <7.3 or HCO3 <15 mmol/L
Capillary ketones >3 mol/L or ++ urinary ketones

Question 3

What is the first step in management of DKA

Answer 3

Fluid resuscitation - dehydration is more lethal than hyperglycaemia

1L saline over 1 hour (or faster if hypotensive) - NO K+ 
1L saline over 2 hours
1L saline over 2 hours
1L saline over 4 hours
1L saline over 4 hours
1L saline over 6 hours 
1L saline over 6 hours

After the first litre, add K to each litre depending on VBG results:
K >5.5 - nil
K 3.5-5.5 - 40mmol KCl
K <3.5 - senior review as additional potassium required

Question 4

What to do after starting fluids for DKA

Answer 4

IV insulin infusion 0.1 units / kg / hour from 50 units human soluble rapid-acting insulin (i.e. Actrapid) in 50ml 0.9% saline

i.e. 70kg = 7 units per hour - max rate 15 units per hour

Question 5

When to start IV glucose in DKA

Answer 5

When the capillary glucose is <14 mmol/L

Give 10% IV glucose at 125ml/hr IN ADDITION to the 0.9% saline - reduce the saline rate to account for the extra fluid

Glucose is used so that insulin can continue to drive more glucose into cells to reduce ketosis and acid production

Question 6

What investigations to do as part of DKA assessment

Answer 6

1. Bloods - FBC, U&E, LFT, CRP, glucose, osmolality
2. Blood culture
3. MSU
4. CXR
5. ECG

Question 7

When to consider HDU admission for DKA

Answer 7

Ketones >6 mmol/L
HCO3 <5 mmol/L or pH <7.1 
GCS <12
SBP <90mmHg
Sats <92% on air
HR >100 or <60 
Potassium <3.5 mmol/L on admission

Question 8

What to do with a patients normal insulin in DKA

Answer 8

Continue long-acting insulin throughout

Start long-acting insulin (Lantus or Levemir 0.25 units/kg once daily s/c) if new presentation

Question 9

What investigations do you need to repeat regularly in DKA

Answer 9

Capillary glucose and ketones hourly

• aim to reduce glucose by 3 mmol/hour
• aim to reduce ketones by 0.5 mmol/hour

Insulin can be increased by 1 unit per hour if target not reached

VBG at 1 hour, 2 hours, then 2-hourly to assess

• acid-base balance - aim to increase HCO3 by 3mmol/hr
• potassium
• glucose

Question 10

When can the patient resume their usual insulin regime at a mealtime after DKA

Answer 10

When the acid-base balance is fully corrected:
i.e. pH >7.3 and capillary ketones <0.6 mmol/L (should occur within 24 hours)

AND the patient is eating and drinking
- if not eating and drinking but normal physiology - then start variable rate insulin infusion

Question 11

What else is important to consider if DKA after fluids, potassium, insulin and glucose

Answer 11

VTE prophylaxis

Education and medication review

Question 12

What is hyperosmolar hyperglycaemic state

Answer 12

The slow development of hyperglycaemia due to illness or dehydration.
This causes hyperosmolality in the intravascular compartment and severe cellular dehydration due to prolonged osmotic diuresis

There is no acidosis or ketosis due to the basal insulin levels which allow enough glucose uptake to prevent the switch to fatty acid metabolism

Question 13

What are the main dangers of HHS

Answer 13

Dehydration

Prothrombotic state

Question 14

What is the risk of over rapid correction of serum osmolality in HHS

Answer 14

Osmotic demyelination syndrome

Question 15

How to confirm diagnosis of HHS

Answer 15

1. Marked hyperglycaemia >30mmol/L without acidosis or significant ketosis
2. Serum osmolality >320mmol/L
3. Hypovolaemia

Question 16

How to calculate serum osmolality

Answer 16

2x Na + glucose + urea

Question 17

How to manage HHS

Answer 17

1. Rehydrate with 0.9% saline - fluids given at similar rate to DKA initially
2. Check serum osmolality hourly initially - adjust fluid rate accordingly to avoid over rapid correction
3. Start IV insulin infusion at 0.05U/kg/hr ONLY IF glucose is not falling with fluids alone OR there is ketosis - but rehydrate first
4. VTE prophylaxis
5. Look for and treat cause
6. Hold metformin for 2 days - it causes a metabolic acidosis

Question 18

Why is it dangerous to give insulin before rehydration

Answer 18

Patients with HHS are extremely fluid deplete due to the prolonged osmotic diuresis (fluid follows glucose by moving out of cells to blood).
When insulin is given before rehydration, glucose in the intravascular space moves into cells and fluid follows.
This may cause cardiovascular collapse due to rapid depletion of intravascular fluid volume

Question 19

Management of hyperglycaemia without DKA

Answer 19

1. Rehydrate if necessary
2. STAT dose of rapid-acting (Novorapid) or short acting (Actrapid) insulin
   - Type 1: 1 unit decreases BM by 3mmol/L (aim BM <12)
   - Type 2 (more insulin resistant): 0.1U/kg (aim BM <14)
3. Identify and treat cause
4. Adjust normal insulin regime as necessary
5. Recheck glucose in 1 hour and reassess

Question 20

Management of hypoglycaemia

Answer 20

Unconscious

• 200ml 10% glucose or 100ml 20% glucose IV stat (repeat as necessary)
• Glucagon 1mg IM (if no IV access - ONCE ONLY)

Conscious but cannot swallow:
- 2 tubes 40% glucose gel around teeth if mild

Conscious and can swallow

• 15-30g fast-acting carbohydrate i.e. 5 glucose/dextrose tablets, 200ml fruit juice, 3-4 teaspoons sugar
• AND long-acting carbohydrates

All:

1. Check capillary glucose 10 mins later and repeat treatment as needed
2. Give long-acting carbohydrate when able to swallow i.e. biscuits, toast
3. Determine and treat cause
4. Reduce dose of insulin / tablets after - don’t omit as risk of rebound hyperglycaemia

Question 21

Causes of hyperglycaemia

Answer 21

1. DKA
2. HHS
3. Steroids
4. Sepsis
5. Missed hypoglycaemics / insulin
6. Pancreatitis
7. Dehydration
8. Last meal / feeds

Question 22

Common causes of hypoglycaemia

Answer 22

Not enough going in

• poor oral intake
• vomiting

More going out

• Insulin excess / sulphonylureas
• Reduced renal function and so reduced drug excretion
• Alcohol
• Abrupt steroid discontinuation