6 May 2012

DKA (Medical students)


DKA is a metabolic state of hyperglycemia, ketosis and acidosis resulting from deficiency of insulin and excess glucagon (gluconeogenesis, glycogenolysis, lipolysis with the formation of ketoacids). Hyperglycemia causes an osmotic diuresis that leads to excessive loss of free water and electrolytes. Resultant hypovolemia leads to tissue hypoperfusion and lactic acidosis. Mortality from cerebral oedema, hypokalaemia and aspiration pneumonia.

Causes

  • Newly diagnosed IDDM
  • Infection is the most frequent cause
  • Poor compliance with insulin regimens.

Presentation

  • Often insidious, especially in toddlers. 
  • Symptoms: polydipsia, polyuria, weight loss, nausea/vomiting, abdo pain, fatigue.
  • Signs: altered mental status, tachycardia, tachypnoea (Kussmaul), acetone odour, shock.

Diagnosis

  • BG >12 mmol/l
  • VBG pH <7.3 or HCO3 <15 mmol/l
  • Ketonuria.

Treatment

  • ITU if coma or shock.
  • Treatment involves gradual and slow correction of hyperglycaemia, keto-acidosis and dehydration with crystalloid and insulin infusions.
  • Fluids: Saline bolus if shocked. Maintenance + Deficit over 48 hours. Initially N saline, followed by saline/dextrose when BG’s falls. 
  • Monitor capillary blood glucose, and serum electrolytes and blood gases, as well as parameters.
  • Bicarbonate is not usually used.
  • Potassium deficit is corrected by adding K to infusion (after serum K result is known).
  • Antibiotics if underlying infection is suspected.