Diabetic ketoacidosis

Question 1

Define

Answer 1

Diabetic ketoacidosis (DKA) is an acute metabolic complication of diabetes that is potentially fatal and requires prompt medical attention for successful treatment. It is characterised by absolute insulin deficiency and is the most common acute hyperglycaemic complication of type 1 diabetes mellitus.

Question 2

What’s the aetiology?

Answer 2

Reduced insulin concentration or action, along with increased insulin counter-regulatory hormones, leads to the hyperglycaemia, volume depletion, and electrolyte imbalance that underlie the pathophysiology of DKA. Hormonal alterations lead to increased gluconeogenesis, hepatic and renal glucose production, and impaired glucose utilisation in peripheral tissues, which results in hyperglycaemia and hyperosmolarity. Insulin deficiency leads to release of free fatty acids from adipose tissue (lipolysis), hepatic fatty acid oxidation, and formation of ketone bodies (beta-hydroxybutyrate and acetoacetate), which result in ketonaemia and acidosis

Question 3

What are the risk factors?

Answer 3

• Inadequate insulin therapy
• Infection
• MI
• Drugs that affect carbohydrate metabolism (corticosteroids, sympathomimetics, thiazides etc.)
• Hispanic or black ancestry

Question 4

What are the symptoms and signs?

Answer 4

• Polyuria
• Polydipsia
• Weight loss
• Weakness
• Nausea and vomiting
• Abdominal pain
• Dehydration
• Tachycardia
• Kussmaul breathing
• Acetone breath
• Altered mental status

Question 5

What investigations would you do?

Answer 5

• Plasma glucose
• VBG (metabolic acidosis – pH<7.3, bicarb <15) ABG (only do if hypoxic or low GCS)
• Capillary ketones (>3mmol/l)
• Urinalysis (ketones)
• U+E (high urea, low Na, high K)
• Creatinine (high)
• LFT (underlying disease)
• Amylase (usually elevated)
• FBC (high WCC)
• Blood cultures (infection)
• CXR (to find cause, infection)
• ECG (above reason)

Question 6

What’s the management plan?

Answer 6

Replace volume then correct metabolic defects

ABC approach
• Start fluids (0.9% saline)
• Insulin
• Monitor capillary blood glucose and ketones hourly and VBG
• Continue fluids and assess need for K
• Consider catheter if no urine passed by 1 hour
• Avoid hypoglycaemia, if glucose <14, start glucose
• Continue insulin until:
o Ketones <0.6mmol/l
o Venous pH >7.3
o Venous bicarb >15mmol/l