Hyperosmolar Non-ketotic Coma (HONC)

Hyperglycaemic Hyperosmolar state



Features

  • Elderly
  • Type 2 diabetes mellitus
  • Marked hyperglycaemia
  • Marked dehydration (over days)
  • Altered level conc. correlates with serum osmolality
  • No significant ketosis and acidosis
  • Exacerbated by glucose drinks / diuretics
  • Teat with GRADUAL normalisation biochemistry
  • Beware co-existing medical conditions / triggers
  • Beware thromboembolism

Diagnostic criteria

  1. Hyperglycaemia ( glucose > 30 mmol/l)
  2. Total osmolality > 340mOsm/kg
  3. Serum bicarbonate >15mmol/l
  4. Urinary ketones < 1+ plus

Management

  • Oxygen
  • ± CVP monitoring to guide fluid replacement
  • NG tube if ↓ level of consciousness
  • Urinary catheter
  • Prophylactic heparin (Innohep), if no contraindications

Osmolality

[2 x (Na+ + K+) + Urea + Glu]

Usually > 350 mOsm/kg


Content by Dr Íomhar O' Sullivan 22/10/2010. Last review Dr ÍOS 15/06/21.