Diabetic ketoacidosis

Pathology

Diabetic ketoacidosis may be a complication of existing type 1 diabetes mellitus or be the first presentation, accounting for around 6% of cases. Whilst DKA remains a serious condition mortality rates have decreased from 8% to under 1% in the past 20 years.

The most common precipitating factors of DKA are infection, missed insulin doses and myocardial infarction

Features

abdominal pain
polyuria, polydipsia, dehydration
Kussmaul respiration (deep hyperventilation)
Acetone-smelling breath ('pear drops' smell)

Diagnostic criteria

American Diabetes Association (2009)	Joint British Diabetes Societies (2013)
Key points glucose > 13.8 mmol/l pH < 7.30 serum bicarbonate <18 mmol/l anion gap > 10 ketonaemia	Key points glucose > 11 mmol/l or known diabetes mellitus pH < 7.3 bicarbonate < 15 mmol/l ketones > 3 mmol/l or urine ketones ++ on dipstick

Management

fluid replacement: most patients with DKA are deplete around 5-8 litres. Isotonic saline is used initially. Please see an example fluid regime below.
insulin: an intravenous infusion should be started at 0.1 unit/kg/hour. Once blood glucose is < 15 mmol/l an infusion of 5% dextrose should be started
correction of hypokalaemia

JBDS example of fluid replacement regime for patient with a systolic BP on admission of 90mmHg and over

Fluid	Volume
0.9% sodium chloride 1L	1000ml over 1st hour
0.9% sodium chloride 1L with potassium chloride	1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride	1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride	1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride	1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride	1000ml over next 6 hours

Please note that slower infusion may be indicated in young adults (aged 18-25 years) as they are at greater risk of cerebral oedema.

JBDS potassium guidelines

Potassium level in first 24 hours (mmol/L)	Potassium replacement in mmol/L of infusion solution
Over 5.5	Nil
3.5-5.5	40
Below 3.5	Senior review as additional potassium needs to be given

Complications of DKA and its treatment

gastric stasis
thromboembolism
arrhythmias secondary to hyperkalaemia/iatrogenic hypokalaemia
iatrogenic due to incorrect fluid therapy: cerebral oedema, hypokalaemia, hypoglycaemia
acute respiratory distress syndrome
acute kidney injury