Tutorial: DKA Flashcards

1
Q

Primarymdefect in T1DM

A

Deficient insulin from B cell

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2
Q

What could precipitate diabetic ketoacidosis (DKA)

A
  1. New diagnosis of T1DM
  2. Not taking insulin
  3. Intercurrent stress (pneumonia, heart attack)
  4. Fasting and not taking enough insulin WHY–> stress hormones
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3
Q

What will happen with deficient [insulin]

A

High HGO and deficient muscle glucose uptake

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4
Q

What will happen with high plasma [glucose]

A

2.Glucose exceeds proximal convoluted tubule ability for reabsorption

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5
Q

Pathophysiology in DKA

A

Insulin deficiency, and high stress hormones (cortisol, catecholamines and GH)

Leads to hyperglycaemia

Leads to osmotic diuresis and dehydration

DEHHYDRATION CENTRAL TO DKA

Fever also increases dehydration

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6
Q

Which is statement is incorrect when [insulin] low

Increased lipolysis rate
Glycerol used to produce glucose in liver
Fatty acids to produce glucose in liver
Fatty acids to produce ketone bodies in liver

A

Fatty acids to produce glucose in liver…

They don’t produce glucose (this is the glycerol from TAGs)…. they produce ketones whichncause a metabolic acidosis

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7
Q

Acid base, which is correct

  1. Low insulin causes reduced bicarbonate production
  2. Bicarbonate production linked to H+ excretion
  3. Excess urinary filtrate inhibits H+ excretion
  4. Bicarbonate is primarily generated in PCT
  5. All of above
  6. None of above
A

2

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8
Q
  1. Needs adequate glomerular filtration for the acid base system to function
  2. Carbonate dehydratase is important in acid base homeostasis
  3. Na excretion is linked to H or K excretion
  4. Acid ketone bodies require increased HCO3 buffering
  5. All correct choose 5
A

5

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9
Q

What is the cause of metabolic acidosis with DKA

A

Reduced [HCO3] in blood because -

  1. impaired production
  2. increased H+ buffering
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10
Q

What happens to the anion gap in ketoacidosis

A

HIGH ANION GAP….

same amount of acids and bases in blood, as blood is neutral….

The reason for the anion gap (i.e. the fact that less anions are recorded than cations) is that some of the anions are not measured in the anion gap eqaution… these are the unknown anions… including phosphate, and ORGANIC ACIDS.

These organic acids dissociate into H+ and an anion (e.g. for lactic acid it splits into lactate and H+). The serum remains neutral because the excess H+ from this organic acid is mopped up, but an increased amount of the negative ion (e.g. lactate) is left behind. So the anion gap will increase, despite same overall amount of anions and cations.

https://www.youtube.com/watch?v=sQnEFVNrY74
FANTASTIC video! (He’s annoying but still!)

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11
Q

What happens to the following ions in DKA:

  1. Water
  2. Na
  3. K (total body levels, plasma levels and urine)
A
  1. Lost in urine (osmotic diuresis)
  2. Lost in urine (during the osmotic diuresis)
  3. Usually, insulin stimulates Na+/K+ ATPase…. so drives K+ into cells. With insulin decifiency in DKA, K+ isn’t driven into cells, so hyperkalaemia. Additionally, H+/K+ ATPase on cells increases activity to bring H+ into cells and neutralise blood, but in doing so forces more K+ out.

THUS:
HIGH SERUM
LOW total body K+ (as it’s all being removed from cells)
INCREASED K+ removal in urine

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12
Q

As well as insulin decifiency what else causes increase sugar levels during DKA

A

Stress hormones

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13
Q

From the flow diagram, what leads to dehydration in DKA

A

Osmotic diuresis due to hyperglycaemia

Hyperventilation loses water as compensation for metabolic acidosis (Kussmaul’s breathing)

fever causes dehydration

so does vomoiting due to acidosis

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14
Q

Clincal features of DKA

A
Dehydration
Insulin, deficiency
Total body potassium deficiency, although plasma [potassium] high
Acidotic
Risk of arrhythmia, infection and dilated stomach
Polyuria and polydipsia due to osmotic diuresis
dehydration
hyperventilation (Kussmaul)
abdominal pain, vomiting
coma
look for precipitating factor
glycosuria  and ketonuria
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15
Q

Inverstigsations for DKA

A
Capillary glucose
Plasma glucose
creatinine, K+, Na+
FBC
Arterial blood gases
amylase (triglyceride)
ECG
CXR
Septic screen
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16
Q

DKA treatment

A
Fluid
Insulin 
Potassium
Bicarbonate
Other measures
17
Q

How is insulin administered to DKA patient

A

Insulin is given as an intravenous sliding scale. This means the capillary glucose is measured once an hour and the insulin administration rate is adjusted according to that capillary glucose.

18
Q

Other measures for DKA patients

A
Cardiac monitor - arrythmias
catheterise
antibiotics
NG tube (gastroparesis)
consider heparin
consider arterial line (very acidotic) and central line (elderly or when cardiac failure)
19
Q

Second phase DKA treamtnet

A

When glucose < 10mmol / litre change to 5% dextrose
continue insulin
continue potassium
may need more saline