Introduction

Diabetic ketoacidosis (DKA) may be a complication existing type 1 diabetes mellitus or be the first presentation, accounting for around 6% of cases. Rarely, under conditions of extreme stress, patients with type 2 diabetes mellitus may also develop DKA.

Epidemiology

  • Incidence: 50.00 cases per 100,000 person-years
  • Peak incidence: 30-40 years
  • Sex ratio: 1:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Pathophysiology

Pathophysiology
  • DKA is caused by uncontrolled lipolysis (not proteolysis) which results in an excess of free fatty acids that are ultimately converted to ketone bodies

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

Clinical features

Features

Diagnosis

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

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
  • long-acting insulin should be continued, short-acting insulin should be stopped

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

FluidVolume
0.9% sodium chloride 1L1000ml over 1st hour
0.9% sodium chloride 1L with potassium chloride1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride1000ml 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 5.5Nil
3.5-5.540
Below 3.5Senior review as additional potassium needs to be given

Complications

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

* children/young adults are particularly vulnerable to cerebral oedema following fluid resuscitation in DKA and often need 1:1 nursing to monitor neuro-observations, headache, irritability, visual disturbance, focal neurology etc. It usually occurs 4-12 hours following commencement of treatment but can present at any time. If there is any suspicion a CT head and senior review should be sought

Prognosis

Whilst DKA remains a serious condition mortality rates have decreased from 8% to under 1% in the past 20 years.