Excessive growth of parts of the body due to overproduction of growth hormone by the pituitary gland
Acromegaly is a rare condition that results from overproduction of growth hormone by the pituitary gland. Over-production of growth hormone causes certain bones, particularly those in the face, hands, and feet, to enlarge. Soft tissues, such as the tongue, also become enlarged. Acromegaly may occur at any age. If excess growth hormone is produced during childhood, the condition causes exaggerated bone growth resulting in excessive height, and is called gigantism (see Growth disorders).
Acromegaly is usually caused by a pituitary tumour. In rare cases, acromegaly occurs as part of multiple endocrine neoplasia, an inherited disorder in which tumours develop in several of the endocrine glands around the body.
If acromegaly develops in adulthood, the resulting physical changes occur almost imperceptibly over a period of years. Sometimes, the condition is detected by comparing old photographs with more recent ones. The following symptoms may become noticeable:
Changes in the shape of the face, such as enlargement of the jaw.
Enlargement of the hands or feet, resulting in a larger glove or shoe size.
Deepening of the voice.
Enlargement of the tongue.
Tingling in the hands and feet.
Increased growth of coarse body hair.
A growing pituitary tumour may press on the brain, causing headaches and loss of the normal field of vision (see Visual field defects) in addition to the symptoms of acromegaly. If not treated, acromegaly may cause serious disorders, such as diabetes mellitus and enlargement of the heart (see Dilated cardiomyopathy), which may lead to chronic heart failure.
Your doctor may arrange for you to have several blood tests. If these tests reveal high growth hormone levels, you may also undergo imaging procedures, such as MRI or CT scanning, to look for a pituitary tumour.
Small pituitary tumours can usually be removed completely by surgery. If a tumour is large or cannot be removed entirely, radiotherapy may be necessary to destroy the remaining tumour cells, or drugs may be given to reduce the production of growth hormone (see Pituitary drugs).
Treatment is usually effective and prevents life-threatening complications from developing. Soft tissues will gradually decrease in size. However, changes in the size of bones cannot be reversed.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.