DKA

Question 1

mechanism

Answer 1

in normal states the body uses carbohydrates for energy
in starvation the liver switches from carbohydrate metabolism and fatty acid synthesis to fatty acid oxidation and ketone body production
in the case of DKA, the lack of insulin means that even when blood glucose is high, the cells cannot uptake glucose (GLUT4 not expressed)
therefore switches to ketoacidosis as the method of energy production

Question 2

typical presentation

Answer 2

gradual drowsiness

D&V in type 1 DM (very rare in type 2)

Question 3

BM test

Answer 3

anyone with:
unexplained vomiting
abdo pain
polyuria
polydipsia
lethargy
anorexia
ketotic breath (acetone being breathed off)
dehydration
coma
deep breathing

Question 4

triggers

Answer 4

infection
MI
pancreatitis
chemo
antipsychotics
wrong insulin dose/non compliance

Question 5

diagnosis

Answer 5

all 3 of:
acidaemia - blood pH <7.3 and/or bicarb <15mmol/L
hyperglycaemia - BM >11mmol/L
ketoanaemia - cap ketones >3mmol/L or ketonuria ++ or above

Question 6

severe DKA

Answer 6

if one or more present at admission
blood ketones >6mmol/L
venous bicarb <5mmol/L
pH<7.1
K <3.5mmol/L
O2 stas <92% on air
systolic BP <90mmHg
pulse <100 or >60
anion gap above 16

Question 7

anion gap

Answer 7

(K+ + Na+) - (Cl- + bicarb)

normal 8-18mEq/L

Question 8

pitfalls in DKA

Answer 8

WCC may be seen in the absence of infection
infections often have no fever - MSU, cultures and CXR. start broad spec ABx if infection suspected
hyponatraemia is common due to osmolar compensation for hyperglycaemia. normal or increased [Na+] indicates severe water loss
ketonuria does not = ketoacidosis - ++may be present after an overnight fast
acidosis but without grossly elevated blood glucose may occur. also consider overdose (eg aspirin) and lactic acidosis

Question 9

recurrent DKA

Answer 9

blood glucose will return to normal long before the levels of ketones in the blood
therefore reducing the insulin dose too soon could lead to a lack of clearance and a return to DKA

Question 10

management DKA

Answer 10

ABC, 2 large bore cannulae
if SBP<90mmHg 500ml saline bolus (2nd bolus and ICU advice if no response)

tests: bloods, urine, ECG, CXR, ABG/VBG

insulin:
50units actrapid added to 50ml saline continuously at 0.1u/kg/h

check VBG for pH, bicarb, glucose and K+ at 1hr, 2hr then 2hrly after that

to avoid hypoglycaemia: when BM <14mmol/L start 10% glucose at 125ml /h alongside saline

continue fixed rate insulin until ketones <0.3mmol/L, venous pH >7.3 and venous bicarb >18mmol/L

urinary ketones do not indicate resolution

Question 11

alcohol

Answer 11

inhibits gluconeogenesis in the liver so in diabetics can lead to a reduced blood sugar
also increases insulin sensitivity, so people taking insulin need to be careful of hypo’s