Diabetic Ketoacidosis

Question 1

Biochemical features of DKA?

Answer 1

increased keto-acids (urine/blood)

increased ketones (breath)

Metabolic acidosis - reduced pH

Metablic acidosis = high anion gap metabolic acidosis (AG) = Na+ - (Cl- + HCO3-)
- AG >16 = metabolic acidosis
- hyperkalaemia

Hyperglycaemia - raised blood glucose

Question 2

DKA causes

Answer 2

infection, new cases of diabetes, insulin management errors, no known cause

!Severe uncontrolled diabetes caused by insulin deficiency!

Question 3

Mechanism of DKA

Answer 3

In DKA, there is excessive glucose, but because of a lack of insulin, this cannot be taken up into cells to be metabolised, so pushing the body into a starvation like state where ketoacidosis is the only mechanism of energy production. The combination of severe acidosis and hyperglycaemia can be deadly

Question 4

Typical picture, clinical presentation of DKA

Answer 4

Gradual drowsiness, vomiting, dehydration in type 1 diabetic (rarely type 2)

Do glucose in all those with unexplained vomiting, abdo pain, polyuria, polydipsia, lethargy, anorexia, ketotic breath, dehydration, coma, or deep breathing

Question 5

Diagnosis of DKA

Answer 5

1. Acidaemia (venous blood pH <7.3 or HCO3- <15.0mmol/L
2. Hyperglycaemia (blood glucose >11.0mmol/L) or known DM
3. Ketonaemia (at or >3.0 mmol/L) or significant ketonuria (more than 2+ on dipstick)

Tests: ecg, urine dispstick and MSU. Blood - capillary and lab glucose, ketones, pH, U&E, HCO3-, osmolality, FBC, blood culture

Question 6

Severe DKA is present if one or more of the following features is present on admission (consider transfer to HDU/ICU):

Answer 6

Blood ketones >6mmol/L
Venous bicarbonate <5mmol/L
Venous/arterial pH <7.0
K <3.5mmol/L on admission
GCS <12
O2 sats <92% on air (assuming no respiratory disease)
Systolic BP <90mmHg
Pulse >100 or <60bpm
Anion gap above 16

Question 7

Complications of DKA?

Answer 7

Cerebral oedema (get help is sudden CNS decline)
Aspiration pnemonia
Hypokalaemia
Hypomagnesaemia
Hypophosphateaemia
Thromboembolism

Question 8

Outline of management plan for DKA

Answer 8

ABC approach, 2 large-bore cannulae

Tests: venous blood gas for pH, bicarbonate, betside and lab glucose and ketones, U&E, FBC, CRP, CXR, ECG

Insulin

Check capillary blood glucose and ketones hourly

Continue fluids and assess need for K+

Consider catheter if not passed urine by 1h, aim for urine output 0.5mL/Kg/h. consider NG tube if vomiting of drowsy. start all patient of LMWH

Avoid hypoglycaemia! when glucose <14mmol/L start 10% glucose at 125mL/h to run alongside saline and prevent hypoglycaemia

Continue fixed-rate insulin until ketones <0,6<mmol/L, venous pH >7.3, and venous bicarb>15mmol/l

Question 9

Insulin administration for DKA

Answer 9

Add 50 units human solutble insulin to 50mL 0.9% saline

Infuse continuously at 0/1 unit/kg/h

continue patient’s regular long-acting insulin at usual doses and times; consider initiating long-acting insulin in newly diagnosed T1DM

Aim for a fall in blood ketones of 0/5mmol/L/h, or a rise in venous bicarbonate of 3 mmol/L/h with a fall in glucose of 3 mmol/L/h

if not achieving this, increase insulin infusion by 1 unit/h until target rates achieved