THYROID DISORDERS -
(A) Hyperthyroidism (Hypersecretion of thyroid hormone).
Graves' disease or Basedow's disease or Parry's disease or exophthalmic goitre. It is a thyroid enlargement (goitre) in which the thyroid secretes excessive amount of thyroid hormone.
It is characterised by exophthalmia (protrusion of eye balls because of fluid accumulation behind them), loss of weight, slightly rise in the body temperature, excitability, rapid heart beat, nervousness and restlessness.
(B) Hypothyroidism (Hyposecretion of thyroid hormone)
(a) Cretinism. This disorder is caused by deficiency of thyroid hormone in infants.
It's character - slow body growth and mental development of reduced metabolic rate.
Other symptoms of this disorder are - slow heart beat, lower blood pressure, decrease in temperature, stunted growth, pigeon chest and protruding tongue and retarded sexual development.
(b) Myxoedema or Gull's disease. It is caused by deficiency of thyroid hormone in adults.
This disease is characterized by puffy appearance due to accumulation of fat in the subcutaneous tissue because of low metabolic rate.
The patient lacks alertness, intelligence and initiative. He also suffers from slow heart beat, low body temperature and retarded sexual development.
(c) Simple Goitre. It is caused by deficiency of iodine in diet because iodine is needed for the synthesis of thyroid hormone. It causes thyroid enlargement. It may lead to cretinism or myxoedema. This disease is common in hilly areas. Addition of iodine to the table salt prevents this disease.
(d) Hashimoto's disease. In this disease all the aspects of thyroid function are impaired. It is an autoimmune disease in which the thyroid gland is destroyed by autoimmunity.