Hyperosmolar Non-Ketotic Coma (HONK)

Clinical Description

Persons at risk: elderly patients

Triad of diagnosis:

• Hypovolemia.
• Hyperglycemia (as high 30mmol/L or 545mg/dl),
• Hyperosmolality (> 320mOsmol/kg; calculated as [2Na+] (mmol/L) + glucose (mmol/L) + BUN (mmol/L))

Signs and Symptoms

• Confused / reduced consciousness and, dehydration.

Treatment

• Fluid replacement is more important than insulin even if blood sugar is high; however, fluids should not be given too rapidly to avoid large electrolyte shifts.
• Give 2 liters Sodium Chloride 0.9% in the first hour, then 1 litre every hour. Adjust to slower rate if elderly patient with risk of heart failure.
• Change to Dextrose 5% when blood sugar approaches normal levels. Aim for blood glucose levels of 180 – 270mg/dl (10 to 15mmol/l) in first 24hrs.
• Insulin should only be given if urine ketones ≥ 2+ at presentation or blood glucose falling at a rate of ≤90mg/dl (5mmol/l) despite adequate rehydration. If there is an infusion pump use rate of 0.05 units/kg/hr. of short acting/soluble insulin; Or give 10iu Soluble Insulin IV stat; this is usually enough.
• Do not try to lower the blood sugar rapidly at all costs by giving high doses of insulin.

Potassium Chloride

• Aim to keep potassium level between 4 to 5mmol/L
• Withhold potassium chloride in the first two liters and do not give > 20mmol/L of K over 1 hour.
• Adjust / individualize insulin treatment when fully conscious and eating as described in section 6.1