15.1 DKA Flashcards
You are asked to review an 18-year-old male in the emergency department who has been found obtunded at home. He is an insulin-dependent diabetic with a history of poor glycaemic control. Capillary blood glucose is 23.4 mmol/l.
a) List the clinical and biochemical findings that confirm severe diabetic ketoacidosis (DKA). (40%)
The presence of any of the following
indicates severe diabetic ketoacidosis,
mandating consultant physician assessment
and consideration of referral for level 2 care:
Clinical findings:
» GCS less than 12 or abnormal AVPU score.
> > Oxygen saturation below 92%
on air (assuming normal baseline
respiratory function).
> > Systolic BP below 90 mm Hg.
> > Pulse over 100 or below 60 bpm.
Biochemical findings:
» Blood ketones over 6 mmol/l.
> > Bicarbonate level below 5 mmol/l.
> > Venous/arterial pH below 7.0.
> > Hypokalaemia on admission (under 3.5 mmol/l).
> > Anion gap above 16
(anion gap = (Na+ + K+) − (Cl− + HCO3−)).
b) Outline the management plan for severe DKA within the first hour. (40%)
Airway:
» 15 l oxygen via non-rebreathe mask.
> > Consider need for immediate intubation
due to reduced conscious
level or respiratory distress.
Respiratory:
» Monitor respiratory rate
and continuous oxygen saturations.
> > Auscultate chest, checking for evidence of underlying infection or heart failure.
Cardiovascular:
> > Check pulse and establish monitoring:
continuous ECG, blood pressure
(initially noninvasive and then intra-arterial).
> > Large bore cannulation.
> > Fluid resuscitate:
• 500 ml 0.9% sodium chloride/15 minutes
if SBP less than 90 mm Hg.
• Repeat if SBP remains below 90 mm Hg.
If no improvement, consider
other underlying causes and
seek senior or critical care input.
• Once SBP greater than 90 mm Hg or
if it is above this value on admission,
1000 ml 0.9% sodium chloride should
be given over an hour.
• Give intravenous potassium if
serum potassium is below the upper
limit of normal range.
If hypokalaemic on admission, seek senior assistance.
Neurological:
» Assess GCS.
Exposure:
» Full examination,
seek underlying cause and manage appropriately.
> > Check temperature.
Insulin:
» Fixed rate intravenous insulin infusion
to start after commencement of fluids
at 0.1 units/kg/h.
> > Continue with the patient’s usual
long-acting insulin.
Investigations:
» Blood ketones.
» Capillary blood glucose.
» Venous plasma glucose.
» Urea and electrolytes.
» Venous blood gases.
» Full blood count.
» Blood cultures.
» 12-lead ECG.
» Chest radiograph if clinically indicated.
» Urinalysis and culture.
» Consider precipitating causes and investigate appropriately.
» Pregnancy test in women of childbearing age.
c) What are the serious complications that can follow the management of DKA? (20%)
> > Hypo- or hyperkalaemia,
with risk of cardiac arrhythmia.
> > Acute pre-renal failure.
> > Hypoglycaemia,
risking cardiac arrhythmia,
brain injury, death.
> > Cerebral oedema
(more likely in children)
due to fluid shifts of DKA,
exacerbated by rehydration.
> > Pulmonary oedema,
rarely,
in susceptible patients such as the elderly or
those with pre-existing cardiac disease
