Hello jammom,
Welcome to the site! As for Cushing's disaease, no it is not typically an autoimmune disease. Cushing's can be caused by pituitary adenomas (ACTH secreating tumors) ACTH stimulates the production of Cortisol from the adrenals. This is the most common cause. Tumors on the adrenal glands (adrenal adenoma) themselves can also cause cushing's. Rarely cancerous tumors elsewhere in the body (Lung's, pancreas) overstimulate the pituitary producing to much ACTH and in turn to much Cortisol. Most likely in the case of your friend, an adrenal adenoma is the cause (therefore removal of the adrenal glands will cure the cushings). It is correct that after removal she will have Addison's. Addison's is however commonly caused by autoimmune disease (anti-adrenal antibodies). In your freinds case the Addison's however is not autoimmune (surgically induced). Addison's is treated mainly with Hydrocortisone (the naturally occuring form of Cortisol) generally doses are given 3 times a day (eg. 15mg-10mg-5mg) this simulates the body's natural daily cortisol production. Additionally a mineralcorticoid (Fludrocortisone) is given (also produced by the adrenals) which regulates the body's salt/water balance. Important is with Addison's that the patient learns to regulate the dosis of Hydrocortisone, in the presence of physical stress (surgery, illness, extreme sport etc.) the dosage must be increased (Cortisol is a stress hormone and would normally be increased in stress situations). A Cortisone identification card should be carried (Medic alert) A life threatening event known as Addison's Crisis must be treated immediately with injection of 300mg Hydrocortison or equivilent. Your freind should carry an emergency injection kit.
I have Addison's (caused by loss of the pituitary hormones ACTH) in my case this was indirectly caused by my MCTD/vasculitis. A reduced blood supply to the pituitary gland (caused by vasculitis event) damaged the pituitary (necrosis), it is no longer able to stimulate the adrenals to produce Cortisol. I also no longer produce other hormones which are stimulated by the pituitary (Thyroid hormone, Growth hormone, and the ovary stimulating hormones the lead to fertility and production of Estrogen/Progesterone.
I wish your friend good luck with the surgery, and treatments. Good luck to you as well.
mfG
Monique