Pituitary dwarfism, also termed hyposomatotrophism, is the result of inadequate production of growth hormone (GH) by the pituitary gland. The lack of production of growth hormone may be due to a lack of development of the pituitary gland, cysts within the gland, infectious diseases which affect the gland, or tumors. Growth hormone has many effects within the body including controlling the growth rate, maintaining the hair coat, and bone and teeth development.

What are the symptoms?

A kitten affected with pituitary dwarfism will fail to grow at the proper rate, though the proportion of the body and head size would be normal. The kitten will generally be much smaller than his or her littermates. The teeth will be slow to develop as will the hair coat, which will tend to remain soft, without the stiffer guard hairs. As they age, kittens with pituitary dwarfism will appear mentally slower than normal kittens. Pituitary dwarfism is very rare in cats, and needs to be distinguished from congenital hypothyroidism. A special blood test can be used to measure the amount of insulin-like growth factor (IGF-I) present. The level in a cat with pituitary dwarfism will be lower than normal.

What are the risks?

Because so many organs are affected by a lack of growth hormone, normal life spans are not to be expected. The kitten may have other hormonal abnormalities such as hypothyroidism and hypoadrenocorticism.

What is the management?

There are no effective treatments for pituitary dwarfism in the cat. There has been some research in using bovine growth hormone, but it's long term effectiveness is unknown.