DKA Flashcards
What causes DKA?
Ketoacidosis is an alternative metabolic pathway used in starvation staes
It is far less efficient and produces acetone as a byproduct
In acute DKA there is excessive glucose but because of a lack of insulin this cannot be taken up tiny cells and metabolised,
This pushes the body into a starvation like state where ketoacidosis is the only mechanism of energy production
Severe acidosis + hyperglycaemia
What are features of DKA?
Gradual drowsiness Vomiting Dehydration Confusion Polyuria Polydipsia Weight loss Abdominal pain
Deep and rapid breathing (Kussmaeul) due to acidosis
Ketotic breath
Shock
Coma
Diagnosis of DKA?
Acidaemia (VBpH < 7.3 or HCO3 < 15mmol/L)
Hyperglycaemia (BM > 11.0mmol/L) or known DM
Ketonaemia (>=3mmol/L) or significant ketonuria (++ on dipstick)
What factors indicate severe DKA?
Blood ketones >6mmol/L Venous HCO3 < 5mmol/L pH <7.1 K < 3.5mmol/L GCS < 12 SaO2 < 92% on air Systolic BP < 90 Pulse <60 or >100 Anion gap > 16
Principles of DKA management?
Fluid Resus Insulin Potassium Acidosis Mx Re-establish oral fluids, SC insulin and diet Treat underlying cause
Describe fluid management of DKA?
If in shock
0.9% saline (10ml/kg)
Correct dehydration gradually over 48 hours
Rapid rehydration may lead to cerebral oedema
0.9% saline + 40mmol/L (or 20mmol/500ml) KCl for first 12h
When blood glucose <14mmol/L use 0.9% saline + 40mmol/L (or 20mmol/500ml) KCl + 5% Glucose
After 12h if plasma sodium level is stable: 0.45% saline/5% glucose with 40mmol/L KCl
How do you calculate the fluids to be replaced in DKA?
Maintenance + dehydration deficit minus any fluid given as resuscitation
What are signs of various degrees of dehydration?
Mild - around 3% weight loss
Moderate - dry mucous membranes and reduced skin turgor, around 5% weight loss
Severe - sunken eyes and reduced cap refill time, around 8% weight loss
8% dehydrated = water deficit of 80ml/kg
What insulin is given in DKA?
Insulin infusion (0.1 units/kg/h)
Started after IV fluids running for 1 hour
Use 1 unit/ml solution of fast acting insulin
Run at 0.1units/kg/h
Cerebral oedema is more likely if insulin started early
Monitor blood glucose hourly
Aim for gradual reduction of blood glucose
Change to a solution containing 5% glucose when blood glucose has fallen 14mmol/L to avoid hypoglycaemia
Once pH > 7.3 and glucose <14mmol/L consider reducing insulin to 0.05units/kg/h
When should you stop IV insulin?
When blood ketone levels are < 1 mmol/L and patient is able to tolerate food.
Give dose of SC insulin
Feed patient
Stop infusion 10-60m after SC insulin
How is potassium corrected?
Due to displacement form cells in exchange for H+ potassium will fall following treatment with insulin and rehydration
Start K replacement as soon as maintenance fluids are started
Continuous cardiac monitoring and 2-4 hourly plasma potassium measurements until it is stable
How is acidosis corrected?
Acidosis will correct with fluid and insulin therapy
Avoid bicarbonate - increased risk of cerebral oedema
What are pitfalls in DKA?
Cerebral oedema - treat with mannitol
Leucocytosis
Infection - MSU, blood culture and CXR, start broad spectrum abx if suspected
Creatinine - some assays for creatinine cross react with ketone bodies so plasma creatinine may not reflect true renal function
Hyponatraemia is common due to osmoloar compensation for the hyperglycaemia/ AS treatment commences, sodium rises as water under cells.
Ketonuria - does not equate with ketoacidosis - anyone may have up to ++ ketonuria after an overnight fast, consider alcohol
Acidosis - without gross elevation of glucose - consider aspirin poisoning
