What is Acromegaly?
Acromegaly is a rare condition caused by the overproduction of somatotropin (also called growth hormone, HGH and GH) which can lead to distorted facial features, enlarged hands, and feet, as well as, cardiac issues.
It is a rare disease that affects about 60 to 70 people per million and 3 to 5 new cases per million people are diagnosed each year.
It is usually diagnosed in adults between the ages of 30 and 40. Before puberty, an increase in GH causes gigantism or giant acromegaly.
The main cause of acromegaly is a benign (nonmalignant pituitary adenoma) tumor in the pituitary gland, a gland in the brain that usually secretes various hormones, including GH.
The symptoms associated with increased production of growth hormone
The symptoms of acromegaly are mainly related to the effects of abnormally high production of GH and another hormone, IGF-1 (insulin growth factor-1), which is “controlled” by GH.
The symptoms are as follow:
- Enlargement of hands and feet
- Changes in the appearance of the face with protruding brows, prominent cheekbones and front bones, thicker nose, thicker lips, gaps between teeth, thicker tongue and a protruding lower jaw.
- Joints and back pain, tingling or pain in the hands due to carpal tunnel syndrome, as the thickening of the bones in the wrist compresses the median nerve.
- Other symptoms such as excessive sweating, fatigue, hearing loss and changes in voice
Symptoms related to the primary cause
Other symptoms are related to the cause, usually, a benign pituitary tumor, which can compress other brain structures and/or reduce the production of other pituitary hormones by increasing pituitary volume:
- Visual disturbances
- Reduction in the secretion of thyroid hormones, which can lead to colds, general slowing down, intestinal constipation, reduced heart rate, weight gain, and sometimes to goiter.
- Reduction of adrenal hormones (fatigue, loss of appetite, reduced hair growth, and hypotension)
- Reduction of sex hormones (menstrual disorders, impotence, and infertility)
- Excessive secretion of GH is sometimes accompanied by increased production of another hormone, prolactin, which can lead to increased breast volume (gynecomastia), milk production and reduced libido in both women and men, and prolonged or interrupted menstrual cycles in women.
- Acromegaly is often associated with other diseases such as diabetes, high blood pressure, sleep apnea, gallstones, nodules, and even thyroid cancer. There is also an increased risk of colorectal cancer, so sometimes more tests are needed (thyroid ultrasound, sleep apnea, colonoscopy, etc.).
The symptoms appear very slowly, which means that the diagnosis usually takes place only after several years of evolution (from 4 to over 10 years). It often happens that it is mainly due to the physical aspect when a person (or his/her surroundings) realizes that he/she can no longer wear rings, has changed the size of his/her shoe and hat.
Sometimes pictures are used to show abnormal changes on the face over time.
Causes and diagnosis
In the vast majority of cases (over 95%), overproduction of growth hormone, which causes acromegaly, is associated with the development of a benign pituitary tumor (pituitary adenoma), a small gland (about the size of a pea) located at the bottom of the brain, just above the nose.
This tumor often appears for no known reason and is labeled sporadic. In other, much rarer cases, acromegaly is associated with a genetic abnormality.
However, the contrast between sporadic and the genetic forms is becoming increasingly difficult to maintain, as sporadic forms (with no other cases in the family) have recently shown that there are also genetic mutations present.
In the rare cases that are due to genetics, there is clearly an increased risk of acromegaly. In general, the diagnosis of one case in a family leads to the screening of other family members.
The diagnosis of acromegaly is quite simple; all you need is a blood test to determine the levels of GH and IGF-1. In acromegaly, there is a high level of IGF-1 and GH in the blood. The final diagnosis is based on a glucose test which is used to see if the levels of GH drop; if the levels of GH do not drop after the introduction of glucose the diagnosis of acromegaly can be made.
Once the hypersecretion of GH has been confirmed, its origin must be found. Currently, the reference test is the MRI of the brain, which can show if there is a tumor in the pituitary gland. In very rare cases, it is a tumor located elsewhere (usually in the brain, lungs or pancreas) that releases another hormone that acts on the pituitary gland, GHRH, which stimulates the production of GH. A more detailed examination is then carried out to determine the origin of this abnormal secretion.
What treatments are available for acromegaly
The surgical treatment is a preferred treatment for acromegaly, intended to remove a benign tumor from the pituitary gland that causes excessive secretion of GH. It can only be performed in the hands of highly experienced neurosurgeons, in this case, neurosurgeons specializing in pituitary surgery.
It is currently performed through the nose (the so-called transsphenoidal route) using an endoscope. Although this is the most logical approach, it is also difficult and could possibly be a source of serious side effects. The aim is to remove as much of the tumor mass as possible without causing any long term side effects.
Medical treatment can supplement or replace surgery when surgery is not possible. Several drugs in the somatostatin inhibitor class are currently prescribed for acromegaly when surgery is not enough or possible to bring down the levels of HGH to an acceptable level. In the cases where surgery was performed and the body no longer secretes the GH, it needs to function normally, HGH injections (Somatropin) can be used. Other drugs, such as dopaminergic, can also be used to inhibit the production of both GH and prolactin which are both secreted excessively in acromegaly.
Radiation therapy for pituitary tumors is currently rarely prescribed because of the potential debilitating side effects that it may cause. However, there are now techniques where the rays are highly targeted, which significantly reduce the harmful effects of radiotherapy (e.g. GammaKnife, CyberKnife) and which can ultimately complement medical and/or surgical treatments.
Acromegaly is a disease that is easy to identify and for which treatment options exist. However, its rarity and very slow evolution mean that its diagnosis and therapeutic management are often delayed, to a stage when some of the symptoms are no longer reversible. Moreover, increases in the size of feet and facial changes are generally not viewed as symptoms of disease, but as age-related changes. Therefore, doctors should always consider the possibility of acromegaly, even if it is very rare. If patients notice an increase in the size of their hats or shoes, they should not overlook it but consult with their doctors to rule out the condition.