29th May 2025

Management

The most important part of treating HHS is aggressive rehydration but there are several factors to consider:

• Rehydration – using an isotonic solution, typically 0.9% saline. An initial bolus should be given followed by an infusion at around 250ml/hour.
• Correction of electrolytes – this should be approached with caution as there is concurrent intravascular dilution and depletion of electrolytes. Potassium replacement should be started when the concentration is 4 – 4.5mmol/L. Other electrolytes should be monitored closely and replaced with specialist input.
• Insulin – this should be avoided initially as it may cause too rapid of a fall in glucose, resulting in cerebral oedema. It may be started later on the advice of an endocrinologist. 
• Monitoring – glucose should be closely monitored as if it falls too fast then cerebral oedema will occur. Osmolarity should be monitored as a marker of response to treatment. Electrolytes should be closely monitored and acted upon accordingly. 
• Treatment of underlying cause – whatever this may be. 

Patients with T2DM must be educated on the symptoms of HHS, common triggering events and when to seek medical attention. If taking insulin, the importance of good compliance should be stressed as to avoid developing HHS.