Symptoms
The excess of growth hormone in your bloodstream can affect various tissues in your body which can make them 'thicken' or 'grow'. So, over time one or more of the following may develop:

• Hands and feet become larger and broader. Your glove and shoe size may increase over the years. You may not be able to get a wedding ring off.
• The skin may thicken (particularly on the face) and become more greasy and sweaty.
• Changes to the face which may include: thickened lips and nose, thickening of the scalp, the jaw becoming more prominent. As the changes develop slowly, they may not be recognised by family or friends. But, looking back at old photographs may suggest your facial appearance has 'thickened' or changed.
• The vocal cords thicken which may cause your voice to deepen.
• Your tongue may enlarge so you may often 'bite your tongue'.
• Thickening of cartilage may cause arthritis in various joints.
• Thickening of the nasal passages can make you snore loudly and may cause obstruction in airflow when you are asleep (sleep apnoea). This can make you have a poor nights sleep with daytime drowsiness.
• 'Carpel tunnel syndrome'. This is where a nerve going through the wrist is squashed by thickened tissue. It can cause pain, tingling and weakness in parts of the hands.

Other effects of too much growth hormone include

• General tiredness and some muscle weakness.
• About 1 in 5 people with acromegaly also develop diabetes as growth hormone counters the effects of insulin.
• High blood pressure develops in about 1 in 3 cases.
• Increase risk of heart disease and stroke. This is probably because of the increase risk of developing high blood pressure and diabetes.
• The risk of developing cancer of the bowel may be slightly increased.

Also, in about 1 in 3 cases, the adenoma also makes too much of another hormone called prolactin. This can cause sexual and menstrual problems, and a milky discharge from the nipple. Many men with acromegaly also develop erectile dysfunction (impotence).

Symptoms caused by the growing tumour
In many cases the tumour remains small and does not cause pressure symptoms. But, in some cases the tumour grows enough to cause pressure on the nearby tissues. This can lead to:

• Headaches.
• Problems with vision. The tumour may press on the optic nerves (the nerves going from the eyes to the brain) which are just next to the pituitary.
• Other normal cells in the pituitary may become squashed and damaged. So, you may develop a lack of other hormones normally made by the pituitary. This can cause an underactive thyroid gland and/or an underactive adrenal gland which can cause various other symptoms.

Other symptoms in children
If you have too much growth hormone before you finish growing then you get a condition called gigantism. In this condition you grow very tall.

Who gets acromegaly?
Acromegaly is rare. About 4 or 5 people in a million develop acromegaly each year in the UK. It mainly affects adults between the ages of 30 and 50. Men and women are equally affected. Rarely, it affects children.

How is acromegaly diagnosed?

• A blood test can measure the level of growth hormone. But, a single test is not reliable. The diagnosis of acromegaly is made by a glucose tolerance test. In this test you drink a sugar drink containing 75 gram glucose. You then have a series of blood tests over two hours. The glucose should lower the blood level of growth hormone, but in acromegaly the growth hormone level remains high.
• A blood test to measure the level of IGF-I (see above) may be measured if acromegaly is suspected. This may also be used as an index of disease activity to assess how well treatment is working.
• An MRI scan (magnetic resonance imaging scan) or CT scan (computed tomography scan) can show the size of the tumour.
• Eye and visual tests will assess if the tumour is pressing on the optic nerve.
• If you are confirmed as having acromegaly, other tests will be needed to see if the tumour is causing a lack other hormones made by the pituitary.

Pituitary Tumors

In over 90 percent of acromegaly patients, the overproduction of GH is caused by a benign tumor of the pituitary gland, called an adenoma. These tumors produce excess GH and, as they expand, compress surrounding brain tissues, such as the optic nerves. This expansion causes the headaches and visual disturbances that are often symptoms of acromegaly. In addition, compression of the surrounding normal pituitary tissue can alter production of other hormones, leading to changes in menstruation and breast discharge in women and impotence in men.

There is a marked variation in rates of GH production and the aggressiveness of the tumor. Some adenomas grow slowly and symptoms of GH excess are often not noticed for many years. Other adenomas grow rapidly and invade surrounding brain areas or the sinuses, which are located near the pituitary. In general, younger patients tend to have more aggressive tumors.

Most pituitary tumors arise spontaneously and are not genetically inherited. Many pituitary tumors arise from a genetic alteration in a single pituitary cell which leads to increased cell division and tumor formation. This genetic change, or mutation, is not present at birth, but is acquired during life. The mutation occurs in a gene that regulates the transmission of chemical signals within pituitary cells; it permanently switches on the signal that tells the cell to divide and secrete GH. The events within the cell that cause disordered pituitary cell growth and GH oversecretion currently are the subject of intensive research.

Non-pituitary Tumors

In a few patients, acromegaly is caused not by pituitary tumors but by tumors of the pancreas, lungs, and adrenal glands. These tumors also lead to an excess of GH, either because they produce GH themselves or, more frequently, because they produce GHRH, the hormone that stimulates the pituitary to make GH. In these patients, the excess GHRH can be measured in the blood and establishes that the cause of the acromegaly is not due to a pituitary defect. When these non-pituitary tumors are surgically removed, GH levels fall and the symptoms of acromegaly improve.

In patients with GHRH-producing, non-pituitary tumors, the pituitary still may be enlarged and may be mistaken for a tumor. Therefore, it is important that physicians carefully analyze all "pituitary tumors" removed from patients with acromegaly in order not to overlook the possibility that a tumor elsewhere in the body is causing the disorder.

Treatment
The goals of treatment are to reduce GH production to normal levels, to relieve the pressure that the growing pituitary tumor exerts on the surrounding brain areas, to preserve normal pituitary function, and to reverse or ameliorate the symptoms of acromegaly. Currently, treatment options include surgical removal of the tumor, drug therapy, and radiation therapy of the pituitary.