DIABETIC KETOACIDOSIS

Question 1

In what proportion of children is diabetic ketoacidosis the presenting feature of previously undiagnosed type 1 diabetics?

Answer 1

6%

Question 2

What is the pathophysiology of diabetic ketoacidosis?

Answer 2

Deficiency of insulin blocks use of glucose leading to hyperglycaemia which leads to ketone build up as fat is metabolised.

As glucose levels exceed the renal threshold, an osmotic diuresis ensues with severe dehydration and loss of sodium and potassium.

Question 3

What are some of the precipitating factors of diabetic ketoacidosis?

Answer 3

Infection

Missed insulin dose

Myocardial infarction

Question 4

What are the symptoms of diabetic ketoacidosis?

Answer 4

Abdominal pain

Polyuria

Polydipsia

Weight loss

Vomiting

Lethargy

Question 5

On examination, what are the signs of diabetic ketoacidosis?

Answer 5

Acidosis causes:

Ketone on breath

Kussmaul breathing: rapid, deep, sighing respiration

Dehydration:

Dry mucous membranes

Loss of skin turgor

Tachycardia, hypotension if severe

Cerebral oedema causes:

Headache

Slowing of pulse and hypertension

Decreased consciousness

Seizures and focal neurological signs

Question 6

What are the diagnostic criteria for ketoacidosis as described by the Joint British Diabetes Society?

Answer 6

Glucose above 11 mmol/L or known diabetes mellitus

pH lower than 7.3

Bicarbonate less than 15 mmol/L

Ketones above 3mmol/L
OR
Urine dipstick shows ++ ketones

Question 7

What might the FBC of a child in diabetic ketoacidosis show?

Answer 7

Raised WCC

Question 8

What is the pH cut off for severe ketoacidosis?

Answer 8

Below 7.1

Question 9

If a child has mild or moderate DKA (pH of 7.1 or above), what percentage fluid deficit should be assumed?

Answer 9

5%

Question 10

If a child has severe DKA (pH below 7.1), what percentage fluid deficit should be assumed?

Answer 10

10%

Question 11

How do we manage a mild or moderate child with diabetic ketoacidosis (pH of 7.1 or above)?

Answer 11

Fluids (0.9% saline) - not as a bolus. Add 5% to their maintenance fluid requirement. Can be oral.

Add 20 mmol of potassium to every 500 mls of fluid as they are likely to be potassium deplete

Start ACTRAPID insulin infusion (0.05-0.1 units/kg in 0.9% saline) 1 or 2 hours after fluids are started

Change fluids to 0.9% saline + 5% glucose once glucose hits 14 mmol/L

Question 12

How do we manage a severe child with diabetic ketoacidosis (pH less than 7.1)?

Answer 12

Fluids (0.9% saline) - not as a bolus. Add 10% to their maintenance fluid requirement. Must be IV

Add 20 mmol of potassium to every 500 mls of fluid as they are likely to be potassium deplete

Start ACTRAPID insulin infusion (0.05-0.1 units/kg in 0.9% saline) 1 or 2 hours after fluids are started

Change fluids to 0.9% saline + 5% glucose once glucose hits 14 mmol/L

Question 13

How do we calculate the maintenance fluid requirement for a child in DKA in ml/hour?

Answer 13

If they weigh less than 10 kg, give 2 ml/kg/hour

If they weigh between 10 and 40 kg, give 1 ml/kg/hour

If they weigh more than 40 kg, give a fixed volume of 40 ml/hour.

Question 14

How do we calculate the deficit fluid requirement for a child in DKA in ml/hour?

Answer 14

(Deficit % x weight) / 48 hours

Remember that fluid replacement in children is always done over 48 hours.

Question 15

A 6 year old boy is brought into A+E with abdominal pain and vomiting. His mother gives a history of weight loss and polyuria. A BM reads 24 and DKA is diagnosed. You are asked to prescribe fluids for this boy. He is 20kg and a blood gas shows a pH of 7.15. What amount of fluids will he need in ml/hour?

Answer 15

Deficit 5 % x 20 kg = 1000 mls

Divide over 48 hours = 21 ml/hr

Plus maintenance 1ml/kg/hr = 20 ml/hr

Total = 41 ml/hour

Question 16

How will the fluid requirement in a child in DKA change if on presentation a bolus of fluid was needed for resuscitation purposes?

Answer 16

If more than 20 ml/kg 0.9% sodium chloride has been given by intravenous bolus, subtract any additional bolus volumes from the total fluid calculation for the 48-hour period ie if 30 ml/kg has been given subtract 10 ml/kg from the calculations.

Question 17

A 60 kg 16 year old girl is brought into A+E with abdominal pain and vomiting and a dropping GCS. Her mother gives a history of weight loss and polyuria. A BM reads 35 and DKA is diagnosed. Her BP on admission is 60/30 but she is eventually resuscitated with 1.8 litres of 0.9% NaCl. A blood gas shows her pH is down at 6.9. You are asked to prescribe fluids to treat her DKA. What amount of fluids will she need in ml/hour?

Answer 17

Deficit 10 % x 60 kg = 6000 mls

Minus 10ml/kg resuscitation fluid = - 600 ml (remember that if more than 20 ml/kg 0.9% sodium chloride has been given by intravenous bolus, you must subtract any additional bolus volumes from the total fluid calculation for the 48-hour period ie if 30 ml/kg has been given subtract 10 ml/kg from the calculations)

Divide over 48 hours = 5400/ 48 = 113 ml/hr

Plus maintenance fixed rate = 40 ml/hr

Total = 113 + 40 = 153 ml/hour

Question 18

What amount a potassium should be added to the fluids of a child in DKA?

Answer 18

20 mmol per 500 mls of fluid

Question 19

What is the dose of insulin that should be given to a child in DKA?

Answer 19

0.05 or 0.1 units/kg/hour by infusion

Remember that this must be 1-2 hours after starting IV fluids, not before

Question 20

Having started a child in DKA on insulin, at what point should you change the fluids from sodium chloride 0.9% to sodium chloride 0.9% + dextrose 5%?

Answer 20

Once the blood glucose level reaches 14 mmol/L

Question 21

Having started fluids and insulin for a child in DKA, how should observe this child over the following hours?

Answer 21

Hourly blood glucose

Neurological status at least hourly

Hourly fluid input:output

Electrolytes 2 hours after start of IV-therapy,
then 4-hourly

1-2 hourly blood ketone levels

Question 22

What are the major complications of diabetic ketoacidosis?

Answer 22

Cerebral oedema

Gastric stasis

VTE

Cardiac arrhythmia - hypokalaemia

Acute respiratory distress syndrome

Acute kidney injury

Question 23

What do children that die in a diabetic ketoacidotic crisis die of?

Answer 23

Cerebral oedema from loss of sodium and rapid fall in glucose due to insulin therapy being too high