[2] Diabetic Ketoacidosis Flashcards Preview

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Flashcards in [2] Diabetic Ketoacidosis Deck (58)
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1
Q

What is diabetic ketoacidosis?

A

A medical emergency with significant morbidity and mortality, characterised by hyperglycaemia, acidosis, and ketonaemia

2
Q

What are the diagnostic criteria for diabetic ketoacidosis?

A
  • Ketonaemia of 3mmol/L and over, or significant ketonuria of more than 2+ on standard urine sticks
  • Blood glucose of over 11mmol/L, or known diabetes mellitus
  • Bicarbonate below 15mmol/L, and/or venous pH less than 7.3
3
Q

What are the limiitations of the diagnostic criteria of diabetic ketoacidosis?

A
  • Hyperglycaemia may not always be present
  • Low blood ketone levels do not always exclude DKA
4
Q

What patients is DKA normally seen in?

A

Patients with type 1 diabetes

5
Q

What % of T1DM patients have an episode of DKA in 1 year?

A

3.6%

6
Q

What % of DKA episodes in hospital patients did not primarily present with DKA?

A

8%

7
Q

Can DKA present in people with type 2 diabetes?

A

It can but people with T2 are much more likely to have a hyperosmolar hyperglycaemic state

8
Q

Who does ketosis-prone T2DM more commonly occur in?

A

Patients who are older, overweight, and non-white

9
Q

What does DKA occur due to?

A

Lack of insulin in the body

10
Q

What is the result of the lack of insulin in the body in DKA?

A
  • Glucose cannot be taken into the tissues, causing glucose levels to spill over into urine
  • Release of free fatty acids from adipose tissue
11
Q

What is the result of glucose spilling over into urine in diabetic ketoacidosis?

A

Water and solutes follow, causing osmotic diuresis leading to polyuria, polydipsia, and dehydration

12
Q

By what process are fatty acids released from adipose tissue in DKA?

A

Lipolysis

13
Q

Why does lipolysis occur in DKA?

A

Because the body has entered starvation mode due to its inability to metabolise glucose in the cells for energy

14
Q

What happens to the fatty acids released in DKA?

A

They are converted into ketone bodies in the liver in a process called beta-oxidation

15
Q

What happens to the ketone bodies in DKA?

A

They are metabolised to produce energy

16
Q

What is the problem with the production of ketone bodies in DKA?

A

They have a low pKa, and therefore turn the blood acidic, producing metabolic acidosis

17
Q

What are the precipitating factors for DKA?

A

There may be no obvious precipitant, but possible factors include;

  • Infection
  • Discontinuation of insulin (deliberate or accidental)
  • Inadequate insulin
  • Cardiovascular disease, e.g. stroke or MI
  • Drug treatmentm e.g. steroids, thiaides, or SGL2 inhibitors
18
Q

What kind of stress has the potential to initiate DKA?

A

Any physiological stress, e.g. pregnancy, trauma, or surgery

19
Q

How long do the symptoms of DKA take to develop>

A

Usually develop within 24 hours

20
Q

What should not delay the time to treatment in DKA?

A

Taking a history

21
Q

What are the symptoms of DKA?

A
  • Polyuria and polydipsia
  • Vomiting
  • Dehydration
  • Altered mental state, even coma
  • Weight loss
  • Weakness
  • Lethargy
22
Q

What investigations are done in DKA?

A
  • Examination
  • Capillary blood glucose
  • Urine dipstick testing
  • Assay of blood ketones if available
  • Blood testing
  • ECG
  • CXR
23
Q

What are the examination signs of DKA?

A
  • Signs of gross dehydration
  • Acetone smell (like pear drops) on breath
  • Tachypnoea or Kussmaul respiration
24
Q

What signs of gross dehydration may be present in DKA?

A
  • Dry mucous membranes
  • Decreased skin turgor/skin wrinkling
  • Sunken eyes
  • Slow capillary refill
  • Tachycardia
  • Hypotension
25
Q

What is Kussmaul respiration?

A

Very deep, slow rhythmic breathing

26
Q

What blood tests may be done in DKA?

A
  • Plasma glucose
  • FBC
  • Electrolytes
  • Urea and electrolytes
  • ABG
  • Plasma osmolality
  • Tests to determine cause if indicated, e.g. CK, amylase, blood cultures etc
27
Q

What happens to plasma glucose in DKA?

A

Elevated

28
Q

What happens to the FBC in DKA?

A

Raised WCC often seen

29
Q

What happens to electrolytes in DKA?

A

Na and K may be raised

30
Q

What happens to urea and creatinine in DKA?

A

Elevated

31
Q

What does the ABG show in DKA?

A

Metabolic acidosis with low pH and high HCO3-

32
Q

What happens to plasma osmolality in DKA?

A

It is raised, but not by as much as in hyperosmolar hyperglycaemic state

33
Q

How do you calculate plasma osmolality?

A

Plasma osmolality = 2( [Na]mmol/L + [K]mmol/L + [urea]mmol/L + [glucose]mmol/L )

34
Q

How high should plasma osmolality be in DKA?

A

290mOsm/kg

35
Q

When might the plasma osmolality suggest an alternative diagnosis of hyperosmolar hyperglycaemic state?

A

If it is higher tahn 320mOsm/kg and there is not significant ketonaemia

36
Q

How is the anion gap calculated?

A

The anion gap = [Na]mmol/L – ( [Cl]mmol/L + [HCO3]mmol/L )

37
Q

What happens to the anion gap in DKA?

A

It is elevated at >13mmol/L

38
Q

What are the differential diagnoses in diabetic ketoacidosis?

A
  • Alcoholic ketoacidosis
  • Hyperosmolar hyperglycaemic state
  • Lactic acidosis
  • Other causes of metabolic acidosis, e.g. aspirin overdose
  • Acute pancreatitis
  • Sepsis without ketoacidosis
  • Acute abdomen
  • Ketoacidosis due to starvation
39
Q

What features on admission indicate the need for HDU/ICU monitoring and central venous access?

A
  • Blood ketones >6mmol/L
  • Venous bicarbonate <5mmol/L
  • Venous/arterial pH <7.0
  • K <3.5mmol/L on admission
  • GCS <12
  • Sats <92% on air (assuming no respiratory disease)
  • Systolic BP <90mmH
  • Pulse >100 or <60 bpm
  • Anion gap above 16
40
Q

How is diabetic ketoacidosis managed acutely?

A
  1. Start fluid
  2. Test VBG for pH, bicarbonate, bedside and lab glucose and ketones, U&Es, FBC, CRP, CXR, ECG
  3. Add 50 units of human soluble insuiln to 50mL 0.9% saline, and infuse continuously at 0.1unit/kg/hour. Continue initiating long-acting insulin in newly diagnosed T1DM.
  4. Assess the need for potassium
  5. Continue fixed rate insulin
  6. Find and treat infection/cause for DKA
41
Q

What fluid should be given in the acute management of diabetic ketoacidosis?

A

1L 0.9% saline over 1 hour.

If systolic BP <90mmHg, then give 500mL bolus over 15 minutes, and reassess. If still <90mmHg, give another 500mL bolus over 15 minutes and seek senior review. If remains under 90mmHg, involve ICU

42
Q

What treatment outcome should be aimed for in the acute management of diabetic ketoacidosis?

A
  • Fall in blood ketones of 0.5mmol/L/hour
  • Rise in venous bicarbonate of 3mmol/L/hour, with a fall in blood glucose of 3mmol/L/hour
43
Q

What should be done if not achieving treatment outcome goals in the acute management of DKA?

A

Increase insulin infusion by 1 unit/hour until target rates are achieved

44
Q

How often should capillary blood glucose and ketones be measured in the acute management of DKA?

A

Hourly

45
Q

How often should VBG be checked in the acute management of DKA?

A

2, 4, 8, and 12 hours, or more frequently if indicated

46
Q

When should fixed rate insulin be continued until in DKA?

A

Until ketones <0.6mmol/L, venous pH >7.3, and venous bicarbonate >15mmol/L

47
Q

When should you consider a catheter in DKA?

A

If not passed urine by 1 hour

48
Q

What urine output should be aimed for in DKA?

A

0.5mL/kg/hour

49
Q

When should an NG tube be considered in DKA?

A

If vomiting or drowsy

50
Q

Who should be started on LMWH in DKA?

A

All patients

51
Q

How is DKA managed once glucose reaches 14mmol/L

A

Start 10% glucose at 125mL/hour to run alongside saline, to prevent hypoglycaemia

52
Q

What is the typical fluid deficit in DKA?

A

100mL/kg

So for an average 70kg man, you need to replace 7L

53
Q

Give an example of a suitable fluid regime in DKA for a 70kg man

A

An example regime is 1L over 1 hour, then 1L over 2 hours, 1L over 2 hours, 1L over 4 hours, 1L over 4 hours, 1L over 8 hours, 1L over 8 hours.

The regimen may not be appropriate for all, so reassess frequently, especially in young, elderly, pregnant, or comorbidities

54
Q

What is the typical potassium deficit in DKA?

A

3-5mmol/kg

55
Q

What causes the potassium deficit in DKA?

A

Plasma potassium falls with treatment, as potassium enters cells

56
Q

Should you add potassium to the first bag of fluids in DKA?

A

No

57
Q

How much potassium should be added to fluids in DKA?

A

It should be based on the most recent VBG.

  • If serum potassium is >5.5mmol/L, don’t add potassium
  • If serum potassium is 3.5-5.5mmol/L, add 40mmol/L KCl to IV fluid
  • If serum potassium <3.5mmol/L, seek help from HDU/ICU
58
Q

What are the complications of diabetic ketoacidosis?

A
  • Cerebral oedema
  • Pulmonary oedema
  • Arrhythmias
  • Myocardial suppression
  • Venous thromboembolism
  • Myocardial infarction
  • Adult respiratory distress syndrome