DKA

Question 1

What is DKA?

Answer 1

Diabetic ketoacidosis - combination of hyperglycaemia, metabolic acidosis and ketonaemia

Question 2

Name the 7 causes/precipitants of DKA

Answer 2

Insulin (poor compliance)
Iatrogenic (change in insulin regime)
Infection
Incision (surgery)
Intoxication (EtOH, other drugs)
Initial (first presentation of T1DM
Infarction

Question 3

What is the biochemical definition of DKA?

Answer 3

Venous pH below 7.35
Positive ketones
BSL above 11.1 mmol/L (usually)

Question 4

Go through the pathophysiology of DKA. What happens to the main electrolytes in DKA?

Answer 4

No insulin = glucose stays in blood. Glucose in blood = osmotic diuresis = polydipsia, polyuria, and dehydration. No glucose in cells = cells are starving so induce liver start to metabolise fats to make ketones. Ketones are acidic = metabolic acidosis.

Electrolytes:

Na+ usually normal or low (osmotic diuresis means that more water is lost than Na+)
K+ - initially elevated from acidosis, insulin deficiency and water loss (false hyperkalaemia), but becomes low in very severe settings
Ca, Cl, Mg - decreased (follow H2O in osmotic diuresis)

Question 5

4 main symptoms of DKA?

Answer 5

Polyuria
Polydipsia
Vomiting
Weight loss
Abdominal Pain

Question 6

What are the first two assessments you should make of a child with DKA?

Answer 6

Degree of dehydration

Level of conscious state

Question 7

Why might the degree of dehydration be overestimated in a child with DKA?

Answer 7

Metabolic acidosis induces peripheral vasoconstriction, so peripheries can look more hypovolaemic than they actually are

Question 8

What sign is specific to DKA?

Answer 8

Kussmaul respiration

Question 9

Name 7 Ix to do with a child with DKA

Answer 9

FBE - WCC can go up in DKA (but really raised would suggest infection)
UEC
Blood glucose
Blood ketones
Venous blood gas (including bicarb)
Urine ketones and glucose
Ix for precipitating cause (especially infection - might need MSU MCS, blood cultures etc)
If newly diagnosed, order T1DM Ix (anti-GAD, insulin antibodies, coeliac serology, TSH and FT4)

Question 10

What are your initial steps in managing a patient with DKA? Go through specific Mxs for each step

Answer 10

D - child with reduced conscious state might turn violent
R - assess consciousness (GCS/AVPU). If unconscious, securing airway and breathing is vital. Also would require NGT (prevent aspiration) and catheterisation (to monitor fluid balance)
S - send for help immediately (endocrinology +/- ICU)
A - secure if unconscious
B - assess need for supplemental O2. assess risk of aspiration. Keep nil by mouth (can give some ice to suck)
C - Assess dehydration and provide ongoing maintenance fluid (0.9% NaCl + KCl) +/- fluid bolus (if mod-severely dehydrated). ECG if potassium is high or low.
DEFG - Don’t Ever Forget Glucose. Measure glucose, start insulin. Put in 2nd IV site to allow for easy blood taking (going to need lots of Ix)

Question 11

What sign is best for determining whether a child with DKA needs a fluid bolus? If they do, what should you give?

Answer 11

Central capillary refill > 2 seconds. If > 2 sec, give 10mL/kg bolus of 0.9% NaCl

Question 12

What is the risk of giving too many fluid boluses in someone with DKA? Why are they so susceptible to this? What is a treatment for this complication?

Answer 12

Risk of too much fluid is cerebral oedema and herniation. Children with DKA are at risk of this because of the intracellular adaptations that occur throughout DKA. DKA is a fairly subacute process (but with an acute presentation) - the glucose takes a while to build up in the blood. As the tonicity of the blood increases, cells have to produce more osmotic agents of their own to match the tonicity of the blood (so they don’t lose all of their intracellular fluid). If you give too much fluid to correct intravascular depletion, this fluid will go into cells as well. As kids have a big brain, a small amount of intracellular swelling = herniation.

If you’ve given too much fluid, give mannitol

Question 13

What type of maintenance fluid should you give a DKA initially?

Answer 13

0.9% NaCl + KCl

Question 14

What BSL do you aim to keep a patient with DKA at? What can you do if their BSL is falling too fast?

Answer 14

5 - 12 mmol/L. Can change fluid to 0.45% NaCl + 5% dextrose + KCl if BSL falling too much. Can even go up to 10% dextrose if really bad. Only turn down insulin infusion rate if BSL continuing to fall on 10% dextrose

Question 15

What are the only 2 C/I to giving K+ in DKA?

Answer 15

K+ > 5.5 mmol/L

Anuric

Question 16

Name 5 things to monitor a patient with DKA for

Answer 16

Fluid balance
Vitals
GCS
Blood glucose and ketones (hourly)
K+ (within 1 hr of starting insulin)
VBG (every 2 hrs initially)
UECs every 2-4 hrs