hyperosmolar hyperglycaemic state (HSS or HONK)

see also:

• DDx of hyperglycaemia
• diabetic ketoacidosis (DKA)
• diabetes mellitus
• insulin
• Western Health procedures (intranet only):
  • Insulin infusion (docx)
  • Initial Management of Hyperosmolar Hyperglycamic State (doc)
  • initial Mx of diabetic ketoacidosis (DKA) (doc)

• formerly known as hyperosmolar non-ketotic coma (HONK)
• type 2 diabetic patients who become unstable for a period of days can develop a severely dehdrated hyperosmolar state due to osmotic diuresis resulting from persistent severe hyperglycaemia
• these patients are critically ill with high morbidity and mortality and require urgent resuscitation and investigation of precipitating cause
• early ICU and endocrine unit liason is advisable
• presence of ketonuria and acidosis should be managed as per diabetic ketoacidosis (DKA) instead of this guideline which has been adapted from the Western Health guideline in 2013.

• blood glucose Level (BGL) > 33 mmol/L
• pH > 7.30
• serum bicarbonate > 15 mmol/L
• urine ketones: absent or small
• serum osmolality >320 mOsm/kg
  • Note - osmolality approximation: [(Na + K) x 2] + urea + glucose
• neurological abnormalities frequently present

• iv access
• start iv fluid Rx to rehydrate (see below)
• bloods for FBE, U&E, glucose, LFTs, lipase, troponin, VBG, blood cultures
• ECG
• CXR
• urinalysis, MSU m/c/s
• consider need for central line if co-morbid conditions such as congestive cardiac failure

• infection
• acute major illnesses such as myocardial infarction, cerebrovascular accident or pancreatitis
• drugs that affect carbohydrate metabolism including glucocorticoids, second-generation antipsychotic agents
• poor compliance with insulin or oral hypoglycaemic regimen
• newly recognised Type 2 Diabetes Mellitus

• patients often have severe intravascular depletion due to prolonged periods of hyperglycaemia resulting in fluid loss from osmotic diuresis.
• usual fluid deficit is around 4-5 litres.
• a typical rate of replacement (tempered by co-morbidities such as history of congestive cardiac failure, ischaemic heart disease (IHD)):
  • Normal Saline 1L – 2L stat, followed by
    • 1L over 2 hours (hrs), then
    • 1L over 4 hrs
• once the blood glucose ≤ 20mmol/L, (aim is to achieve this gradually over the 1st 24 hrs), commence 8 hourly 1L 5% Dextrose in addition to Normal Saline until re-hydration is complete.

• use pump set up with Actrapid 100 units in 100mls Normal Saline = 1 unit/millilitre (ml)
• discard first 10-20mls before connecting to patient to saturate insulin binding sites on plastic tubing
• initial insulin infusion rate is 0.02 units/kg/hr
• target BGL range: 15-20mmol/L within first 24 hrs
• check BGL hourly
  • if BGL < 15mmol/L, cease insulin infusion and contact endocrine unit
  • if BGL ≥ 15mmol/L and falling by ≥4mmol/hr, reduce insulin infusion rate by 1 unit/hr
  • if BGL ≥ 15mmol/L and not falling by ≥2mmol/hr, increase insulin infusion rate by 1 unit/hr
• if intravenous access is temporarily not possible, subcutaneous quick acting insulin can be given (low doses eg 4-6 units, and observe response over next 2 to 4 hours)
• when the patient is recovering and eating normally, they should be stepped down to a basal bolus or premixed insulin regimen. Ultimately many patients will return to their usual medications if appropriate or initiated on oral hypoglycemic agents if newly diagnosed Type 2 Diabetes.

• these patients are at high risk of developing hypokalaemia during Rx
• while on an insulin infusion, K+ levels should be checked every 2 hours for the first 6hrs. After 6 hrs, K+ level should be checked every 4-6hrs.
• KCl infusion rates:
  • K+ < 3.5 mmol/L: 20mmol/hr
  • K+ 3.6-4.5 mmol/L: 10mmol/hr
  • K+ 4.5-5.5 mmol/L: 5mmol/hr
  • K+ > 5.5mmol/L: nil

• these patients have a high risk of developing DVT so should be given prophylactic dose enoxaparin

• hyperglycaemia causes a reduction in serum sodium levels
• predicted sodium levels once glucose level normalises can be determined via:
  • Predicted Na+ concentration = Measured Na+ concentration + 1/3 BGL
• the initial hydration fluids should almost always be Normal saline, but ½ Normal Saline may be needed if the predicted Na+ (after correction, using this formula) continues to be >145 mmol/L after significant fluid hydration (e.g. 3 litres 0.9% Normal Saline)