The pituitary Underaction Simmond’s disease
This rare disorder is due to destruction, partial or total, of the anterior lobe of the pituitary.
It may result from thrombosis of the vessels supplying the gland in association with post-partum haemorrhage (Sheehan’s syndrome) or from the presence of a pituitary tumour.
Apathy, weakness, loss of libido, amenorrhoea and atrophy of breasts and testes result. There is pallor from loss of pigment and the hair is scanty. Significant loss of weight is unusual.
Thyroid activity is reduced and is shown by thyroid function estimations and the urinary 17-ketosteroids are reduced often to less than 2 mg. per day (Normal Values p. 523). A lateral X-ray of the skull may show enlargement of the sella turcia.
Diabetes insipidus
This disorder is also rare. It results from destruction of the posterior pituitary lobe, idiopathic or from local inflammation or neoplasm.
The striking feature is gross polyuria, up to 10 litres of low specific gravity urine being passed daily with consequent intolerable thirst, dehydration, constipation and loss of weight unless sufficient fluid is drunk to balance the loss.
Overaction
Pituitary tumours
Acromegaly is usually associated with a pituitary tumour. Symptoms may be due to the presence of the tumour or to oversecretion of the growth hormone. Fatigue but not loss of weight may be complained of but is not prominent. Hypothyroidism may develop later.
Arising in the growth period it takes the form of gigantism. Secondary diabetes develops in about 25 % of cases.
Other disorders of the pituitary glands and its hypothalamic control include Forbes-Albright syndrome (galactorrhea-amenorrhea caused by chromophobe adenoma of the pituitary), Chiari- Frommel syndrome (persistent galactorrhea and amenorrhea after pregnancy), panhypopituarism, SIADH (syndrome of inappropriate secretion of antidiuretic hormone), iatrogenic pituitary disorders, and some other unspecific pituitary disorders.
Thyroid Underaction Hypothyroidism
Etiology – Deficient secretion in the thyroid gland is seen in:
Congenital goiter or cretinism
Simple parenchymatous goiter occasionally. Lymphadenoid goiter or Hashimoto’s disease, which appears to result from an autoimunie response to thyroglobulin.
Patients treated by partial thyroidectomy, following which the incidence of hypothyroidism has been found to rise to 6 per cent after 10 years.
After I131 therapy the incidence is as high as 29 per cent after 10 years.