A 5-year-old boy presents to Accident & Emergency with a one-day history of abdominal pain and vomiting. He weighs 40 kg and has no past medical history of note.


Observations on triage: Temperature 36.5°C, pulse 90, blood pressure 100/70, SpO2 98% on room air.


On examination, his abdomen is soft with mild generalised tenderness, and bowel sounds are present.


Initial investigations are as follows:

||||
|---------------------------|:-------:|--------------------|
|Sodium|124 mmol/L|135 - 145|
|Potassium|5.5  mmol/L|3.5 - 5.3|
|Chloride|85 mmol/L|95 - 106|
|Urea|8 mmol/L|2.5 - 7.8|
|Creatinine|100 µmol/L|60 - 120|
|Non-fasting Glucose|30.5 mmol/L|< 6.1|
|Ketones (Serum)|4 mmol/L|< 0.6|


Arterial blood gas:

||||
|--------------|:-------:|------------------|
|pH|7.15|7.35 - 7.45|
|PaO₂|12 kPa|11 - 15|
|PaCO₂|4 kPa|4.6 - 6.4|
|Bicarbonate|14 mmol/L|22 - 30|


Which is the next most appropriate prescription to administer?

Options:
explanation: This patient has presented with diabetic ketoacidosis, meeting the criteria of hyperglycaemia, acidosis and ketonaemia. A resuscitation fluid bolus of maximum 10-20ml/kg 0.9% normal saline should be given initially. It should not exceed this amount due to the increased risk of cerebral oedema. Subsequently, the maintenance fluid volumes should be calculated, and the volume deficit gradually replaced over the next 48 hours. The initial resuscitation fluid bolus should be subtracted from the maintenance fluid volume if the patient is not in shock
name: 400 ml bolus of 0.9% normal saline over 30 minutes
label: a
answer: yes
explanation: This is reserved for symptomatic hyponatraemia with a depressed level of consciousness and a high risk of cerebral oedema, which may occur if fluid administration is given too rapidly. **This should not be given without discussing with a senior first!** In diabetic ketoacidosis, the sodium levels should always be corrected for hyperglycaemia
name: 100 ml of 2.7% hypertonic sodium chloride over 15 minutes
label: c
answer: no
explanation: This **should not** be given to children and young people with diabetic ketoacidosis. It should only be reserved for special situations in which the patient has compromised cardiac contractility caused by life-threatening hyperkalaemia or severe acidosis, and only after discussion with a senior. The initial metabolic acidosis should resolve upon treatment with intravenous fluids and an insulin infusion
name: Intravenous sodium bicarbonate
label: e
answer: no
explanation: This would be a suitable maintenance fluid regimen. Maintenance fluid volumes for children in DKA can be calculated as reccommended by the BPSED DKA guideline as: 100ml/kg/day for the first 10kg of bodyweight, 50ml/kg/day for weight between 10-20kg and then 20ml/kg/day for each additional kg above 20kg. For a 40kg boy, it would be (100ml x 10kg) + (50ml x 10kg) + (20ml x 20kg) = 1000ml + 500ml + 400ml = 1900ml over 24 hours
name: 1900 ml of 0.9% normal saline over 24 hours
label: b
answer: no
explanation: This would be one of the treatments for hyperkalaemia. However, this should not be given as a fixed rate insulin infusion would be started for the initial management of diabetic ketoacidosis, which would drive potassium into cells and cause the K levels to fall. Potassium replacement should be added to bags of maintenance fluid unless the patient has K levels above the upper limit of normal
name: Oral calcium resonium
label: d
answer: no

Correct answer: a


Learning point: In diabetic ketoacidosis (DKA), an initial resuscitation fluid bolus of 10-20 ml/kg of 0.9% normal saline is recommended to restore intravascular volume and improve circulation.