HORMONAL DISORDERS: THE PITUITARY GLAND

The pituitary gland is only peanut-sized but produces nine different hormones. Disorders of the pituitary involve over or under secretion of one or more of these hormones.

Hypopituitaryism, or Simmond’s Disease, involves a loss of secretions of the anterior pituitary usually resulting from head injury or from post-partum haemorrhage. This leads to a loss of hormones stimulating growth, pigmentation, sexual development, thryoid and adrenal function, and loss of prolactin, which will cause breast milk to dry up in lactating mothers. If hypopituitaryism occurse before puberty, the child remains short and sexually underdeveloped.

Diabetes Insipidus can result from injury to the posterior lobe, causing loss of ADH (antidiuretic hormone), which normally enables the kidneys to conserve water by concentrating urine. Signs and symptoms of this will be copious amounts of very dilute urine, thirst, constipation, and nocturia. Treatment involves the administration of synthetic ADH as nasal drops.

Acromegaly is the over-production of growth hormone due to a benign tumour, called as adenoma. This can lead to the enlargement of hands, feet, jaw, and all soft tissues. This in turn can cause a general coarsening of the features, a thick tongue, fatigue, aches and pains, and increased sweating. An expanding tumour can give rise to headaches and visual defects resulting from pressure on the nearby optic nerve. It very rarely occurs in children, where it will cause giantism.