Management of Diabetic Emergencies Flashcards
What causes DKA
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
How to confirm a diagnosis of DKA
Glucose >11 mmol/L (or known diabetes)
pH <7.3 or HCO3 <15 mmol/L
Capillary ketones >3 mol/L or ++ urinary ketones
What is the first step in management of DKA
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
What to do after starting fluids for DKA
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
When to start IV glucose in DKA
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
What investigations to do as part of DKA assessment
- Bloods - FBC, U&E, LFT, CRP, glucose, osmolality
- Blood culture
- MSU
- CXR
- ECG
When to consider HDU admission for DKA
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
What to do with a patients normal insulin in DKA
Continue long-acting insulin throughout
Start long-acting insulin (Lantus or Levemir 0.25 units/kg once daily s/c) if new presentation
What investigations do you need to repeat regularly in DKA
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
When can the patient resume their usual insulin regime at a mealtime after DKA
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
What else is important to consider if DKA after fluids, potassium, insulin and glucose
VTE prophylaxis
Education and medication review
What is hyperosmolar hyperglycaemic state
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
What are the main dangers of HHS
Dehydration
Prothrombotic state
What is the risk of over rapid correction of serum osmolality in HHS
Osmotic demyelination syndrome
How to confirm diagnosis of HHS
- Marked hyperglycaemia >30mmol/L without acidosis or significant ketosis
- Serum osmolality >320mmol/L
- Hypovolaemia
How to calculate serum osmolality
2x Na + glucose + urea
How to manage HHS
- Rehydrate with 0.9% saline - fluids given at similar rate to DKA initially
- Check serum osmolality hourly initially - adjust fluid rate accordingly to avoid over rapid correction
- 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
- VTE prophylaxis
- Look for and treat cause
- Hold metformin for 2 days - it causes a metabolic acidosis
Why is it dangerous to give insulin before rehydration
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
Management of hyperglycaemia without DKA
- Rehydrate if necessary
- 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) - Identify and treat cause
- Adjust normal insulin regime as necessary
- Recheck glucose in 1 hour and reassess
Management of hypoglycaemia
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:
- Check capillary glucose 10 mins later and repeat treatment as needed
- Give long-acting carbohydrate when able to swallow i.e. biscuits, toast
- Determine and treat cause
- Reduce dose of insulin / tablets after - don’t omit as risk of rebound hyperglycaemia
Causes of hyperglycaemia
- DKA
- HHS
- Steroids
- Sepsis
- Missed hypoglycaemics / insulin
- Pancreatitis
- Dehydration
- Last meal / feeds
Common causes of hypoglycaemia
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
