PREPARATION FOR PITUITARY SURGERY?

 PREPARATION FOR PITUITARY SURGERY?       6 June 2014
QUESTION-Patient with Non functioning ptuitary adenoma (NFPA) has ant pituitary hormone defciency with borderline low cortisol, low FT4 , FT3 and very low Testosterone.  He is planned for surgery.
Obviously trophic hormomes need to be replaced pre operatively, first with glucocorticoid (GC), then with thyroxine, lastly testosterone
 1. What GC would you choose (HC vc Pred) and why?
 2. How many days after starting GC you would start thyroxine.
 3. Pre operative dose of GC
 4. Post operative management of continuing replacement hormones and when to test HPA axis.
 Many thanks for your attention.  Naswrin Moin

RESPONSE-Thanks for this. I usually use hydrocortisone replacement as one can measure the levels and as the drug is short-acting one can look at the cortisol levels before the morning dose and see if there has been any recovery post-operatively:
I generally use 10mg on rising, 5mg at lunchtime and 5mg in the late afternoon. Prednisolone is longer-acting and can be used once-daily, but remember it will cross-react in the cortisol assay. Actually, pre-operatively you could use either.
I start thyroxine a few days later, around 2-3 days. The reason for the delay is to prevent an Addisonian crisis, and 48-72h should be adequate. if this is pre-operative and you think there may be recovery then liothyronine is better as this has a short- half-life and can be stopped one week after surgery and the thyroxine levels re-assessed then.
For surgery, I give hydrocortisone 100mg iv/im as pre-medication, and then 50-100mg 6-hourly for the first 24 hours and then taper the dose rapidly downwards. We then replace with oral hydrocortisone and re-test all axes one week later. For the HPA axis dynamic testing may be required, but if you use a Synacthen test then you must wait at least 6 weeks. Best wishes, Ashley Grossman