Pituitary Gland

There are some organs in the body that don’t get enough credit.   When was the last time you thought about your pituitary gland, for example?  I can tell you that, despite its anonymity, none of us would be alive without it.  It’s only the size of a pea and nestles quietly at the base of the brain.   Its traditional title was “conductor of the endocrine orchestra”, but really it is more like first violin, being bossed around by the hypothalamus which sits just above it.  Flowing out from, or through, the pituitary are hormones which affect the adrenal glands, the ovaries and testes, the thyroid, the kidneys, the uterus and the breasts.  It also generates growth hormone.

Pituitary tumours are not uncommon, and some don’t cause any problems at all, but if they grow too large pressure on the adjacent optic nerves can result in visual problems.  The gland is really hard to access surgically, and the best approach is through the nose and sphenoid sinuses which strikes me as incredibly clever. 

In general practice the pituitary problems we see are:

  1. Prolactinoma – a benign tumour which generates too much prolactin (the hormone that stimulates breast milk production).  Most are controlled with medication
  2. Cushing’s disease – once again a benign tumour, but this time producing ACTH which overstimulates the adrenal glands and causes symptoms like a prolonged overdose of steroids.  Generally, this need surgery.
  3. Craniopharyngioma – this is a puzzling condition where cells left over from embryonic development overgrow. This is a slow process so symptoms may develop anywhere between childhood and old age. Unfortunately, the whole gland has to be removed, so afterwards the patient has to have all the pituitary hormones replaced and balanced for the rest of their life.  
  4. Rarely the pituitary can be underactive due to infection, trauma, haemorrhage or an autoimmune process.

If we extend this article to the hypothalamus then disorders are rare.  However, there can be a problem with over or underproduction of ADH.  ADH, or vasopressin, switches off urine production, especially at night.  It is sometimes given to children to reduce bedwetting.  There are a number of medical conditions that can cause too much ADH, in which case the body will retain fluid, or not enough, so the patient has huge urine output and thirst. The latter is called diabetes insipidus, not to be confused with diabetes mellitus which is due to reduced insulin production in the pancreas.