Diabetic Ketoacidosis

Question 1

Define Diabetic Ketoacidosis

Answer 1

Acute metabolic complication of diabetes characterised by:
Hyperglycaemia
Ketonaemia
Acidosis

with rapid onset of symptoms

Question 2

Aetiology of Diabetic Ketoacidosis

Answer 2

Starvation - alternative metabolic pathway to glucose metabolism -> acetone production
Diabetes - lack of insulin - excess glucose cannot be absorbed in cells -> severe acidosis and hyperglycaemia

Associated with T1DM (inadequate insulin therapy or infection)
Also caused by MI, stroke, drugs (steroids, thiazides, pentamide)

Question 3

Risk factors for Diabetic Ketoacidosis

Answer 3

Inadequate/inappropriate insulin therapy 
MI 
Infection
Pancreatitis
Stroke
Acromegaly
Hyperthyroidism 
Drugs (steroids, thiazides, pentamide)
Cushing's

Question 4

Presenting symptoms of Diabetic Ketoacidosis

Answer 4

Abdominal pain and vomiting 
Dehydration 
Gradual drowsiness
Polyuria, polydipsia
Polyphagia
Lethargy 
Anorexia 
Severe: coma, deep breathing

Question 5

Signs of Diabetic Ketoacidosis

Answer 5

Tachycardia and hypotension
Ketotic/acetone breath 
Dehydration: poor skin turgor,  prolonged capillary refill
Kussmaul respiration (deep and rapid)
Hypothermia

Question 6

Criteria for Diabetic Ketoacidosis diagnosis

Answer 6

Acidaemia (venous pH <7.3 or bicarb <15)

Hyperglycaemia (glucose >11/known DM)

Ketonaemia (>3mmol/L) OR significant ketonuria (>++)

Question 7

Investigations for Diabetic Ketoacidosis

Answer 7

VBG/ABG: metabolic acidosis (ABG used if hypoxia present)
Plasma glucose: hyperglcuaemia
Capillary/serum/urine ketones: elevated

Look for precipitating factor e.g. CXR for infection, ECG for electrolyte imbalances or MI

Question 8

Criteria for severe Diabetic Ketoacidosis

Answer 8

pH <7.0
Ketonaemia >6mmol/L
Bicarb <5
Potassium <3.5
GCS <12
Sats <92
Brady/Tachycardia
Anion gap <16
Systolic BP <90

Question 9

Management for Diabetic Ketoacidosis

Answer 9

1. 1L 0.9% saline over 1 hour (add 500mL boluses over 15mins if BP <90)
2. Send blood tests for ketoacidosis

(If HYPOKALAEMIC - give POTASSIUM before insulin)

3. Insulin, 50 units to 50ml 0.9% saline and infuse + continue long-acting insulin
4. Consider catheter or NG tube (vomiting or drowsy) and catheter if no urine output
5. When glucose <14 mmol/L -> start 10% glucose
6. Continue fix rate insulin until ketones < 0.6 mmol/L
7. Treat cause

Question 10

Complications of Diabetic Ketoacidosis

Answer 10

Cerebral oedema
Aspiration pneumonia
Hypokalaemia/magnesaemia/phosphataemia
Thromboembolism

Question 11

Prognosis Diabetic Ketoacidosis

Answer 11

Mortality rate 5% in experienced centres
Death often caused by the underlying illness
Prognosis worsened at extremes of age and with coma or hypotension