Need for Steroids

Why do people with brain tumours need steroids?
Steroids, in the form of dexamethasone, are extremely effective in reducing the swelling that results from the tumour. They do NOT reduce the size of the tumour itself (the only exception being primary lymphoma of the brain). Some tumours cause more swelling than others e.g. malignant gliomas and meningiomas seem to create an extraordinary amount of vasogenic oedema (swelling). Once the tumour has been removed the steroids can be stopped. The prescription of dexamethasone does not replace a deficiency in the patients own steroid production.

Can steroids be stopped "cold turkey"?
The short answer is yes but there are 3 situations where they need to be tapered slowly. If the patient has been on steroids for any length of time, usually more than 2 weeks, the body gets a little lazy and stops production of its own (intrinsic) steroids (cortisol). Of course, the body will sense the need to secrete its own cortisol eventually, but this may take a few days. The longer the patient takes extrinsic steroids, the longer it takes to return to normal cortisol production. The second situation is when there is residual tumour. Even small amounts of tumour can generate enormous degrees of swelling resulting in a worsening of symptoms such as headache when the steroids are stopped. Finally, tumours that involve the pituitary gland may destroy cortisol production, and similarly, surgery to remove tumours from the pituitary region may result in diminished ability or total inability to secrete cortisol. To determine the ability of the body to resume cortisol production requires special tests and consultation by an endocrinologist.

Why can't a patient with a brain tumour take steroids indefinitely?
Unfortunately, steroids have many bad side effects apart from the obvious one of depressing intrinsic cortisol production. They reduce the ability of the brain to recover from an insult. This is called "plasticity". They suppress the immune system resulting in more chance of infection. They worsen and sometimes "cause" diabetes. In high doses they can cause Cushing's Syndrome. This is a condition that is characterised by protein wasting, fat redistribution causing a fat face and abdomen, thinning of the skin, osteoporosis, bruising, acne, psychosis etc.