What is diabetic ketoacidosis?
A state of uncontrolled catabolism associated with insulin deficiency, primarily seen in type I diabetics
What is the pathogenesis behind diabetic ketoacidosis?
In the absence of insulin, hepatic glucose production accelerates, and peripheral uptake by tissues such as muscle is reduced. Rising glucose levels lead to an osmotic diuresis, loss of fluid and electrolytes, and dehydration. This results in plasma osmolality rising and renal perfusion falling. Vomiting leads to further loss of fluid and electrolytes.
In parallel, rapid lipolysis occurs, leading to elevated circulating FFA levels. These are broken down to fatty acyl-CoA within the liver cells, and are subsequently converted to ketone bodies within the mitochondria. Accumulation of ketone bodies produces a metabolic acidosis.
What factors contribute to the acidosis that develops in DKA?
- Accumulation of ketone bodies produces a metabolic acidosis.
- Progressive dehydration impairs renal excretion of hydrogen ions and ketones, aggravating the acidosis.
Why do individuals become dehydrated in DKA?
- Rising glucose levels lead to an osmotic diuresis, loss of fluid and electrolytes, and dehydration.
- Vomiting leads to further loss of fluid and electrolytes.
What are the most common circumstances which somebody develops a DKA?
- Previously undiagnosed diabetes
- Interruption of insulin therapy
- The stress of intercurrent illness
What are symptoms of someone with DKA?
- Weight loss
- Abdo pain
What are signs of DKA?
- Dry mucus membranes
- Sunken eyes
- Ketotic breath
- Kussmaul resp.
- Altered mental state
Up to 5% can present in coma
Why do individuals with DKA have abdominal pain?
Acidosis causes ileus
What is Kussmaul's breathing?
Also described as ‘air hunger’, Kussmaul’s breathing is typified by deep, rapid inspirations.
What is the mechanism behind kussmaul's breathing?
Kussmaul’s breathing is an adaptive response to metabolic acidosis. By producing deep, rapid inspirations, anatomical dead space is minimised, allowing for more efficient ‘blowing off’ of carbon dioxide, thus decreasing acidosis and increasing pH.
Why do individuals with DKA get acetone breath?
Build up of ketones
What criteria are used for the diagnosis of DKA?
What criteria are used to diagnosis acidaemia in DKA?
Venous pH < 7.3 mmol/L
Bicarb < 15 mmol/L
What criteria would you use to diagnose Ketonaemia in somoene with DKA?
Blood ketones > 3 mmol/L
What criteria would you use to diagnose ketonuria in DKA?
2+ on dipstick
What criteria would you use to diagnose hyperglycaemia in someone with DKA?
Blood glucose > 11.0 mmol/L
What tests would you do in someone with suspected DKA?
- Bedside - Urine dipstick, cap glucose/ketones, ECG
- Bloods - FBC, U+Es, VBG/ABG if GCS <8, CRP, lab glucose, Blood Cultures
- Imaging - CXR
When would you suspect severe DKA?
1 or more of following criteria:
- Pulse >100 or <60
- Systolic BP <90 mmHg
- GCS <12 or abnormal AVPU
- O2 saturation <92% on air (assuming no resp disease)
- Blood ketones >6 mmol/L
- Venous Bicarbonate <5 mmol/L
- Venous/arterial pH <7.0
- Hypokalaemia on admission <3.5 mmol/L
- Anion gap > 16 mmol/L
What immediate actions would you take in the immediate management of someone with DKA?
- ABCDE - get 2 large bore cannulas in
- Confirm diagnosis - H+ > 45 or HCO3 < 18 or pH < 7.3 on VBG
- Check - U&Es, lab Blood Glucose, urine or blood ketones
- Record time of arrival
If someone had severe DKA, where would you manage them?
Consider moving to HDU/ITU and call for senior help
What actions should you take within the first 60 minutes of admission in someone with DKA?
- Commence Fluids - 1L NaCl 0.9% over 1 hr within 30 mins of admission
- Commence soluble insulin - IV 6 units/hour within 30 mins of admission
- Record NEWS score
Following inital management of DKA with fluids and insulin within the first hour of admission, how would you continue management over the next 3 hours (hours 1-4)?
- Monitoring: SEWS, ECG, GCS, Lab Glucose, U&Es and HC
Stepwise fluid replacement
- Hour 2 - 1L NaCl 0.9%
- Hour 3-4 - 500mls/hour NaCl 0.9% (+/- KCL based on K+ review)
- Check cap glucose hourly - look for a drop
If, when managing someone for DKA, their blood glucose falls below 14.0 mmol/L within the first 4 hours, how would you manage them?
Maintain Blood Glucose - between >9 mmol/L and ≤14 mmol/L
- Continue NaCl - 0.9% at 400mls/hour + KCL until end of hour 4
- Reduce insulin to 3 units/hour
- Commence Glucose - 500mls 10% glucose with 20 mmol KCl at 100ml/hour
What insulin regime would you initially start someone on in DKA?
What rate would you give NaCl at in someone with DKA in the first 2 hours?
1L per hour
What rate would you give someone fluids with DKA in hours 3 and 4 post admission?
Drop from 1L/hour to 500 mL/hour
When should a senior consultant be called?
- Severe DKA
- Cerebral oedema
- Hypokalaemia on admission
- Reduced consciousness
When would you consider dropping the insulin dose someone is on from 6 units/hour to 3 units per hour?
When blood glucose <14 mmol/L
When considering prescribing KCL for someone with DKA, how would you determine what to give them?
- None if anuric or K+ > 5 mmol/L
- 10 mmol if level 3.5-5 mmol/L
- 20 mmol if level <3.5 mmol/L
When would you consider restarting s/c insulin regimen?
When bicarbonate is normal and patient is eating and drinking
How fluid deplete are individuals in DKA when they first present?
When would you stop I.V insulin and fluids in someone with DKA?
30 minutes after sc insulin regimen has begun
What is the maximum rate of KCL administration?
No greater than 20 mmol/hour
If glucose level rises during management of DKA within the first 4 hours of treatment, what should you do?
Continue glucose therapy, adjust insulin to maintain BG between 9-14 mmol/L
What are signs of cerebral oedema in someone with DKA?
- Reduced conscious level
What would you do if an individual with DKA had not passed urine in the first hour post admission?
Consider catheterising them - aim for output of 0.5 ml/kg/hr
Why do you give glucose therapy within first 4 hours if someone had a BG of < 14 mmol/L?
To prevent hypoglycaemia
If someone presented with a SBP < 90mmHg in DKA, what fluids would you give them?
500 ml Bolus NaCl 0.9%
When would you consider supplementing someone with K+?
When K+ drops below 5 mmol/L
If someone in DKA was vomiting, what would you consider?
Insert NG tube
What are complications of DKA?
- Cerebral oedema
- Aspiration pneumonia
- Arterial/venous TE
Why can cerebral oedema occur in DKA?
Excessive rehydration and use of hypertonic fluids may sometimes be responsible.
What are the main criteria used to confirm the diagnosis of DKA?
- Glucose > 11 mmol/L
- pH < 7.3, HCO3 < 15
- Serum ketones > 3 mmol/L or urinary ketones ++