Diabetic Ketoacidosis

Question 1

Define Diabetic Ketoacidosis

Answer 1

Acute metabolic complication of diabetes characterised by the biochemical triad of hyperglycaemia, ketonemia an acidaemia with rapid onset of symptoms.

Question 2

What differentiates mild, moderate, and severe DKA

Answer 2

Mild DKA: venous pH 7.2- 7.29 or bicarbonate < 15 mmol/l. Assume 5% dehydration

Moderate DKA: venous pH 7.1-7.19 or bicarbonate < 10 mmol/l. Assume 7% dehydration

Severe DKA: venous pH less than 7.1 or serum bicarbonate < 5 mmol/l. Assume 10% dehydration

Question 3

What causes DKA and what may precipitate it

Answer 3

Complication of T1DM

Precipitating events
Insulin (non-adherence)
Infection
MI
Stroke
Surgery, trauma
Pancreatitis
Chemotherapy, hyperthyroidism, Cushing’s steroids, thiazides, antipsychotics etc.

Question 4

What is the pathophysiology behind DKA

Answer 4

Ketoacidosis (alternative metabolic pathway used in starvation states, which produces acetone as a by-product Due to the lack of insulin, the excess glucose cannot be absorbed in cells to be metabolised → hyperglycaemia + acidosis due to ketones)

Question 5

What are the symptoms of DKA

Answer 5

Gradual drowsiness, lethargy, confusion
Unexplained vomiting, abdominal pain, polyuria, polydipsia, anorexia, coma or deep breathing
Dehydration in T1DM
Polyphagia
Fruity smell on breath
Preceding history of:
Increased thirst and urinary frequency
Weight loss
Visual disturbance

Question 6

What are the signs of DKA

Answer 6

Weight and height (measure dehydration)

Obs: hypotension, tachycardia

General
Dehydration: dry mucous membranes, reduced skin turgor, sunken eyes, prolonged >CRT
Poor peripheral perfusion
GCS, Lethargy, drowsiness, decreased level of consciousness
Ketotic/acetone breath
Kussmaul respiration - rapid and deep respiration
Hypothermia

Question 7

What investigations should be done for DKA

Answer 7

Capillary glucose: >11
Urine dipstick: Glucose +++, ketones ++
ECG: look for precipitation factors or hypokalaemia

Blood gas: Metabolic acidosis
Ketones: >3 mmol/L
Blood glucose: >11
FBC, U&Es, LFTs, Amylase

Rule out infections: throat swab, blood cultures, CXR

Question 8

What is the management for DKA

Answer 8

Immediate admission to hospital

1. A-E assessment and resuscitation
2. Fluid resuscitation (10ml/kg bolus of 0.9% saline over 1h)
3. Full clinical assessment (GCS, weight, investigations)
4. Start fluid replacement (maintenance + deficit) and re-assess
5. Ensure all fluids contain 40mmol/L KCL (definitely before insulin given)
6. 1-2h after fluids: Insulin (50 units human soluble to 50mL saline), 0.05 units/kg/hour
7. Re-assess: GCS, blood glucose and ketones, fluid status
8. Consider catheter if urine has not passed within 1 hour, or NG tube if vomiting or drowsy
9. When Glucose <14mmol/L → start 5% glucose and reduce insulin infusion rate to 0.05
10. Continue insulin until blood ketones <0.6mmol/L (urine ketones remain positive)

Question 9

What is the definition of DKA resolution

Answer 9

pH >7.3 and
blood ketones < 0.6 mmol/L and
bicarbonate > 15.0mmol/L

Question 10

What are the complications of DKA

Answer 10

Cerebral oedema (headache, irritability, slowing pulse, rising BP, papilloedema) → hypertonic saline + mannitol
Aspiration pneumonia
Hypokalaemia
Hypomagnesaemia
Hypophosphatemia
Thromboembolism
Femoral vein thrombosis (very sick children with a. femoral line inserted

Question 11

What is the prognosis for DKA

Answer 11

Mortality rate 5% in experienced centres
Death is usually caused by the underlying illness that causes the hyperglycaemia or ketoacidosis
Prognosis worsened at extremes of age and in the presence of coma and hypotension