Acromegaly is a disease caused by an excess of growth hormone (also called somatotropic hormone or GH for Growth Hormon) production. This leads to a change in the appearance of the face, an increase in the size of the hands and feet and also of many organs, which are the main symptoms and signs of the disease.
It is a rare condition, affecting approximately 60 to 70 cases per million people, which represents 3 to 5 cases per million people per year.
In adults, it is usually diagnosed between the ages of 30 and 40. Before puberty, the increase in GH causes gigantism or giganto-acromegaly.
The main cause of acromegaly is a benign (non-cancerous) tumor of the pituitary gland, which is located in the brain and normally secretes several hormones, including GH.
The symptoms of acromegaly
1) related to the increased production of growth hormone
- The symptoms of acromegaly are primarily related to the effects of abnormally high production of GH and another hormone, IGF-1 (Insulin Growth Factor-1) which is “controlled” by GH :
- increased hand and foot size;
- a change in the appearance of the face, with a bulging forehead, protruding cheekbones and eyebrows, a thickened nose, thickened lips, a gaping of the teeth, a thicker tongue, a “curved” chin;
- joint pain (arthralgia) or back pain (spinal pain), tingling or pins and needles in the hands related to carpal tunnel syndrome due to the fact that the bone thickening in the wrist compresses the median nerve;
- Other symptoms, such as excessive sweating, fatigue, hearing loss, voice changes, etc.
2) related to the cause
– Other symptoms are linked to the cause, that is to say, most often to the benign tumor of the pituitary gland which, by increasing the volume of the latter, can compress other brain structures and / or decrease the production of other pituitary hormones:
• headache (headache);
• visual disturbances;
• decrease in the secretion of thyroid hormones causing chilliness, general slowing down, constipation, slowing down of the heartbeat, weight gain, sometimes with the existence of a goiter;
• decrease in the secretion of adrenal hormones (fatigue, loss of appetite, reduction in hair growth, hypotension, etc.);
• decrease in the secretion of sex hormones (menstruation disorder, impotence, infertility, etc.).
The excess GH secretion is sometimes accompanied by an increase in the production of another hormone, prolactin, which can cause an increase in the size of the breasts in men (gynecomastia) secretion of milk and a decrease in libido in both women and men, lengthening or stopping of menstrual cycles in women …
– Acromegaly is often accompanied by other disorders such as diabetes, high blood pressure, sleep apnea, gallbladder stones, nodules, even thyroid cancer, and there is also an excess of colon cancer, hence some additional research sometimes requested (ultrasound of the thyroid, sleep apnea assessment, colonoscopy, etc.).
Symptoms appear very slowly, which means that the diagnosis is usually made only after several years of evolution (from 4 to more than 10 years). The diagnosis is often based on physical appearance, when the affected person (or those around him) notices that he can no longer put on his rings, has changed shoe size and hat size.
Sometimes, it is also photographs that show abnormal changes in the face over time.
Causes of acromegaly
In the vast majority of cases (more than 95%), the hypersecretion of growth hormone that causes acromegaly is related to the development of a benign tumor of the pituitary gland (pituitary adenoma), a small gland (about the size of a chickpea), located at the bottom of the brain, about the height of the nose.
This tumor most often occurs unexpectedly: it is then qualified as “sporadic”. In other cases, much rarer, acromegaly is linked to a genetic abnormality: there are other cases in the family and it may be associated with other pathologies.
Nevertheless, the opposition between sporadic and familial forms is increasingly difficult to maintain, insofar as, in sporadic forms (without other cases in the family), it has recently been shown that there are also genetic mutations at the origin of the disease.
Risk factors for acromegaly
In the rare cases of familial forms, there is of course an increased risk of acromegaly. In general, the diagnosis of a case in the family leads to screening of other family members.
Diagnosis of acromegaly
The diagnosis of acromegaly is quite easy (but only when you think about it), as it involves taking a blood test to measure the level of GH and IGF-1. In acromegaly, there is an elevated level of IGF-1 and GH, knowing that GH secretion is normally intermittent, but in acromegaly it is always high because it is no longer regulated.
The definitive biological diagnosis is based on the glucose test. As glucose normally decreases GH secretion, the oral administration of glucose allows to detect, by successive blood tests, that in acromegaly GH secretion remains high.
Once GH hypersecretion is confirmed, its origin must be found. Today, the reference examination is a brain MRI which may show a pituitary tumor. In very rare cases, it is a tumor located elsewhere (most often in the brain, lung or pancreas) which secretes another hormone acting on the pituitary gland, GHRH, stimulating the production of GH. A more extensive workup is then performed to find the origin of this abnormal secretion.
Treatment of acromegaly
Treatment of acromegaly involves surgery, medication and, more rarely, radiation therapy.
Surgical treatment is the preferred treatment for acromegaly, with the goal of removing the benign tumor of the pituitary gland that causes the hypersecretion of GH. It can only be performed by very experienced hands, in this case those of neurosurgeons specialized in pituitary surgery.
Nowadays, it is done by nasal approach (so-called trans-sphenoidal approach), either by microsurgery (using a microscope) or by endoscopy. If this approach is the most logical, it is also difficult and a potential source of side effects. In some cases, prior medical treatment is performed; in other cases, the goal is to remove as much tumor mass as possible (tumor reduction surgery) to improve the subsequent response to medical treatment.
Medical treatment can either complement surgery or replace it when surgery is not possible. Several drugs of the somatostatin inhibitor class are now prescribed for acromegaly. Delayed forms are currently available that allow for spaced injections. There is also a GH analogue which, “by taking the place of GH”, allows its action to be stopped, but this requires several daily injections. Other drugs, such as dopaminergics, can also be used in acromegaly.
Radiotherapy of the pituitary gland is rarely prescribed today because of its side effects. Nevertheless, there are now techniques where the rays are highly targeted, which greatly limit the harmful consequences of radiotherapy (GammaKnife, CyberKnife for example), and which can eventually complement medical and/or surgical treatment.
Our doctor’s opinion about acromegaly
Acromegaly is a disease that is easy to identify and for which treatments exist. Nevertheless, its rarity and its very slow evolution mean that its diagnosis and therapeutic management are often delayed, at a stage where certain disorders are often no longer reversible. Moreover, the increase in height and facial changes are not usually understood as symptoms, but as changes related to aging. For physicians, the possibility of acromegaly should therefore always be kept in mind, even though its occurrence is very rare. For patients, acromegaly highlights the fact that any change, even as seemingly trivial as an increase in hat size or shoe size, can be a sign of a treatable disease.