diabetic ketoacidosis

Question 1

definition

Answer 1

disordered metabolic state that occurs in the context of absolute or relative insulin deficiency and is accompanied by an increase in counter-regulatory hormones i.e. glucagon, adrenaline, cortisol and growth hormone

Question 2

DKA can theoretically occur in

Answer 2

type 1 and type 2 diabetes but is much more common in type 1

Question 3

lack of insulin results in

Answer 3

no glucose entering the cells causing hyperglycaemia

Question 4

because glucose cannot enter hepatocytes the production of

Answer 4

production of oxaloacetate is reduced

Question 5

at the same time in adipocytes

Answer 5

the lack of glucose results in the breakdown of triglycerides into free fatty acids by the process of lipolysis

Question 6

the free fatty acids then enter the bloodstream and

Answer 6

travel to the liver where they undergo beta oxidation and are converted to acetyl-co-a

Question 7

because of the reduction in oxaloacetate and the increase in counater-regualtroy hormones

Answer 7

• the acetyl-co-A produced cannot enter the TCA cycle so it has only one pathway it can go through which is ketogenesis to produce ketone bodies
• also the release of counter-regulatory hormones increase proteolysis producing more substrate for hepatic gluconeogenesis worsening the hyperglycaemia and causing an osmotic diuresis as water is lost with the glucose in the urine

Question 8

the 3 ketone bodies produced are

Answer 8

acetone, beta-hydroxybutyrate, acetylacetate

Question 9

acetone

Answer 9

cannot be metabolised by the body so it is excreted on the breath and is responsible for the sweet smell described in DKA

Question 10

D-3 hydroxybutyrate and acetyl acetate

Answer 10

dissociate it the blood producing hydrogen ion causing a metabolic acidosis and also they cause the increased excretion of electrolytes such as sodium and potassium

Question 11

tests for the biochemical diagnosis of DKA

Answer 11

• ketonaemia
• ketonuria
• blood glucose
• bicarbonate
• venous pH

Question 12

Ketonaemia is measured from

Answer 12

betahydrocybutyrate

Question 13

values of ketonaemia

Answer 13

greater than 3mmol/L (but in most cases is elevated above 5mmol/L)

Question 14

ketonuria is measured from

Answer 14

acetoacetate

Question 15

values of ketonuria

Answer 15

greater than 2+ on standard uric dipstick

Question 16

blood glucose levels

Answer 16

greater than 11mol/l (but usually is way higher at around 40mmol/l)

Question 17

bicarbonate values

Answer 17

less than 15mmol/l (in severe cases its less than 10mmmol/l)

Question 18

venous pH

Answer 18

less than 7.3

Question 19

potassium in DKA

Answer 19

hyperkalemia greater than 5.5mmol/l

Question 20

creatinine is

Answer 20

normally elevated because muscle is degraded to produce protein for hepatic gluconeogenesis

Question 21

other biochemical markers

Answer 21

hyponatraemia, elevated lactate, elevated amylase

Question 22

WCC is normally

Answer 22

elevated (around 25) but this does not necessarily mean infection is present

Question 23

remember that

Answer 23

euglycaemic diabetes can occur in rare cases and blood glucose levels will be normal

Question 24

common causes of DKA

Answer 24

• non-compliance with insulin
• alcohol or illicit drug use
• infection/sepsis
• first presentation of type 1 diabetes in small number of cases

Question 25

presentation of DKA

Answer 25

nausea, vomiting, abdominal pain, Kausmalls respiration, acetone smell on breath and rarely a coma

Question 26

all DKA cases should be managed in

Answer 26

HDU

Question 27

management of DKA 3 most important things

Answer 27

- IV fluids, IV insulin and replace potassium

Question 28

IV fluids used in DKA

Answer 28

- replace 1-4 litres over the first hour, replace one more litre in the next hour, and over the next 4 hours replace another litre - use 0.9% sodium chloride initially and when blood glucose levels fall to about 15mmol/l switch to dextrose

Question 29

IV insulin used

Answer 29

0.1 units per kg per hour

Question 30

replace potassium because

Answer 30

even though DKA initially causes hyperkalaemia its treatment causes a hypokalemia

Question 31

complications of DKA

Answer 31

- cerebral oedema - cardiac arrest - adult respiratory distress syndrome - aspiration of gastric contents

Question 32

cerebral oedema occurs because

Answer 32

hyperglycaemia results in an osmolar gradient cousing water to shift from the intra-cellular fluid to the extra-cellular fluid space and contraction of the cell volume

Question 33

who does cerebral oedema mostly occur in

Answer 33

children with 1 in 4 cases being fatal

Question 34

management of cerebral oedema

Answer 34

in ICU with Mannitol

Question 35

cardiac arrest because

Answer 35

hypokalemia can cause ventricular fibrillation

Question 36

adult repsiraotryh distress syndrome (ARDS) caused by

Answer 36

lung damage and release of inflammatory mediators results in increased capillary permeability and non-cariogenic pulmonary oedema

Question 37

aspiration of gastric contents occurs due to

Answer 37

dilatation of the stomach which causes gastroparesis

Question 38

reason for hypokalaemia in DKA

Answer 38

Diabetic ketoacidosis is associated with dehydration and profound loss of electrolytes, in particular sodium and potassium. Untreated diabetic ketoacidosis results in a metabolic acidosis which acts on cells to cause potassium efflux and H+ influx. In addition, insulin deficiency also results in potassium efflux. Therefore untreated DKA can be associated with normal or even high serum potassium levels even though the osmotic diuresis has caused a profound total body potassium deficiency. When DKA is treated with insulin, potassium then moves from the extracellular space to the intracellular space, which can result in a profound hypokalaemia. It is therefore very important to keep a close eye on the potassium levels. Potassium will often be required before and/or during insulin treatment.