CASE

A 5 yo boy is brought to the Emergency Department by his mother. She tells you that he is sleepy and doesn't look well. He has been drinking a lot of water and passing a lot of urine over the past two days.
He has no past history. Immunisations are up to date.
Vitals are: GCS 14-15, T 37.3, PR 117, RR 25, Sats 98% RA, BP 85/52
A bedside BSL is 27mmol/L

Your working diagnosis is newly diagnosed diabetes and potential Diabetic Ketoacidosis (DKA)

In terms of DKA, which of the following is true?
(a) Although a serious disease, it is not associated with mortality in children > 3yo
(b) The mainstay of treatment is rapid intravenous fluid delivery, usually 20mL/kg of Normal Saline and repeat
(c) The most important part of the treatment is insulin delivery, in the form of a bolus and then an immediate infusion
(d) Cerebral oedema is a feared complication, although there is evidence that subclinical oedema is present in some, at presentation
(e) Potassium supplementation is not required in children

What Predisposes patients to Cerebral Oedema?

1. < 5yo
2. New Onset Diabetes
3. Late presentation
4. Severe dehydration
5. Severe Disease pH <7.1
6. Large fluid load given
7. Early initiation of insulin, or insulin bolus
8. Low HCO3
9. Reduced levels of consciousness

Most of the studies are small or retrospective or both. However the rate of development of cerebral oedema has not changed, so we need to potentially change the way we approach patients.
In a case-controlled UK study, those children receiving insulin in the first hour and large volumes of fluid in the first four hours, had an increased risk of cerebral oedema. 
Edge JA, Jakes RW, Roy Y, et al. The UK case-control study of cerebral oedema complicating diabetic ketoacidosis in children. Diabetologia 2006;49:2002-9. 

When does Cerebral Oedema occur and how does it present?

There is a rapid onset of progressive neurological deterioration.
The most common period is 4-12 hours post commencement of treatment.
The symptoms and signs include:

How to Diagnose DKA: ​How do we classify DKA?

In order to diagnose DKA there must be:
BSL > 11mmol/L  PLUS
Venous pH <7.3  AND/OR HCO3 < 15mmol/L
​There must also be ketonuria/ketonaemia

We can use the pH or the HCO3 to classify the severity of DKA
HOW DO WE CLASSIFY MILD DKA?

HOW DO WE CLASSIFY MODERATE DKA?

HOW DO WE CLASSIFY SEVERE DKA?

Initial Resuscitation

One of our greatest concerns in the unwell child is the presence of shock. This is recognised in an unwell child, with very poor perfusion i.e.., increased capillary refill time, mottled extremities and thready rapid pulse. You can tolerate a systolic blood pressure of (70 + 2 x age)mmHg
Early, rapid and appropriate resuscitation is the key.
Haemodynamic compromise is not that common in children with DKA.
FLUID RESUSCITATION: WHAT AND HOW MUCH?

How much fluid to give?

In DKA in children we can take two approaches:
(i)  Estimate the fluid losses by calculating the weight loss.
​(ii) Estimate clinically the level of dehydration

There are potential issues with both of these. Firstly there may not be a previous and recent weight on the child and you will have to estimate. There may also be a greater weight loss due to insulin deficiency driven catabolism, resulting in an overestimate of fluid loss.
​BEWARE: OVERSTIMATION OF FLUID DEFICIT AND REPID FLUID RESUSCITATION PREDISPOSE TO CEREBRAL OEDEMA.

If you were to clinically assess dehydration, what would be the features of mild, moderate and severe dehydration and what percentage would you ascribe to each?

• MILD
• MODERATE
• SEVERE

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The child is normally well and there may be features that are just clinically detectable: MAX 3%

There will be dry mucous membranes, and reduced skin turgor MAX 5%

Dry mucous membranes, reduced skin turgor, poor capillary refill, sunken eyes, cold peripheries MAX 8%

How should the fluid be given?

Patients with mild disease may tolerate oral fluids. If a child is vomiting, IV fluids must be considered, however a single dose of Ondansetron, may facilitate oral rehydration.

In Moderate to Severe Disease the DEFICIT should be replaced over 48 hours.

In this patient you have assumed  5%, what is the deficit?
(a) 750mL
(b) 1000mL
(c) 1250mL
(d) 1500mL
​(e) 2000mL

We can't just give the deficit over 48 hours, we must also give the maintenance over that 48 hours.
The maintenance dose per 24 hours for this 5 yo boy is:
(a)  1200mL
(b)  1500mL
(c)  1750mL
(d) 2000mL
(e) 3000mL

But Wait! Two More things will determine how fast to give the fluid!

The Sodium and the Osmolality
Correct the Na for hyperglycaemia
Na = measured Na + [ 2x (glucose -5.5)]/5.5
This child's glucose was 27mmol/L
His Na was 132mmol/L
Corrected Na is 132 + (2 x (27-5.5))/5.5 = 140mmol/L

If the Na >150mmol/L regardless of osmolality, dehydration correction should occur over 72 hours

Calculating Osmolality = 2 x (Na + K) + Gluc. If > 310 = Hyperosmolality

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PLEASE NOTE: Be sure to discuss with the Endocrine/Paediatric Team and your Emergency Specialist if any of the following exist:

• Neonatal DKA
• Hypernatraemia
• Hyperosmolality
• Hyperkalaemia
• Anuria

In all others proceed as below.

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What type of Fluid?

What about Potassium?

We know that potassium levels at presentation are not an accurate guide to the total body potassium stores. Once insulin commences and acidosis is corrected, the potassium levels will drop.
​0.9% NaCl + 40mmol of KCL is an appropriate fluid to start with. Do not add K if the patient is hyperkalaemic or anuric.
Maximum potassium replacement should be 0.3 mmol/kg/hr.

What about INSULIN?

Insulin decreases the blood sugar level and suppresses lipolysis and ketogenesis. It is required in moderate and severe DKA. Fluid alone may be enough in mild cases.

​In mild cases:short acting subcutaneous insulin (Actrapid) 0.1-0.2 U/kg every 4-6 hours In very young children i.e. < 5yo give 0.05U/kg

When to start insulin and how much to give in moderate to severe cases.

What would you do if hypoglycaemia (BSL < 4mmol/L)? 2 correct answers:
(a) Stop the insulin infusion completely
(b) Stop the insulin infusion for up to an hour
(c) Give 2mL/kg of 10% Dextrose over 3 minutes
​(d) Give 5mL/kg of 10% Dextrose over 10 minutes

What about Sodium Bicarbonate?

(a) NaHCO3 is a safe drug to use in acidosis, especially if pH < 7.3
(b) Use 50ml of NaHCO3 in all acidotic DKA with pH < 7.3
(c) Use NaHCO3 when monitoring potassium levels in DKA
(d) NaHCO3 is contraindicated when the BSL is > 15mmol/l
​(e) NaHCO3 is contraindicated in DKA

What would you do if you recognised Cerebral Oedema?