Yes it is exactly that, a diabetic pump which is adapted to infuse hydrocortisone.  The doses and time changes are all worked out to suit the individual’s needs, and the dose can be as low as 0.01, or even 0 for a period and then precise the amount you need is slowly and continuously infused over the day at these different rates, so you do not get the side effects such as weight etc. This way you do not get the high and lows you do with tablets and the hydrocortisone goes straight into the bloodstream so none is lost in the stomach. It is very all very clever, Professor Hindmarsh from Great Ormond Street London worked all this out.