Acromégalie

The acromégalie (of the Greek akros " haut" or " extrême" and megalomaniacs " grand" - enlarging of the ends) is a hormonal disorder which causes an abnormal increase in the size of the foot S and Main S and a deformation of the face with the passing of years.

It appears when the gland Hypophyse produces an excess of Growth hormone (hGH). In general, it is about a hypophyseal adenoma , i.e. a benign Tumeur (derivative of the Somatotrophe S, a type distinct from cells) which produces hGH.

Its evolution is very slow and the diagnosis is often delayed. The hormonal load subjects hard the organization and that causes a great tiredness. The face is very reached by the Syndrome dysmorphic.

Features that result from high level off hGH gold expanding tumor include:

  • Software tissue swelling off the hands and feet (early sign)
  • Brow and lower jaw protrusion (enlarging jaw and hat size)
  • Enlarging hands (boxing ring size)
  • Enlarging feet (shoe size)
  • Arthritis and Carpal tunnel syndrome
  • Teeth spacing increase
  • Heart failure (medical major problem)
  • Compression off the Optic chiasm leading to loss off vision in the outer visual fields
  • Diabetes mellitus
  • Hypertension -->

Causes

In 90% of the cases, the disease is caused by a benign tumor in the Hypophyse.

adenoma. Thesis tumors produce excess GH and, ace they expand, compress surrounding brain tissues, such ace the optic nerves. This expansion the causes headaches and visual disturbances that are often symptoms off acromegaly. In addition, compression off the surrounding normal pituitary tissue edge alter production off other hormones, leading to exchanges in menstruation and breast discharge in women and Impotence in men.

There has off marked variation in spleens GH production and the aggressiveness off the tumor. Summon adenomas grow slowly and symptoms off GH excess are often not noticed for many years. Other adenomas grow rapidly and invade surrounding brain areas gold the sinuses, which are located near the pituitary. In general, younger patient to tends cuts more aggressive tumors.

Most pituitary tumors arise spontaneously and are not genetically inherited. Many pituitary tumors arise from has genetic deterioration in has individual pituitary concealment which leads to increased concealment division and tumor formation. This genetic changes, but Mutation, is not present At birth, goal is acquired during life. The change occurs in has embarrassment that regulates the transmission off chemical signals within pituitary concealments; it permanently switches one the signal that such the concealment to divide and secrete GH. The vents within the concealment that causes disordered pituitary Concealment growth and GH oversecretion currently are the subject off intensive research.

In few has patient, acromegaly is caused not by pituitary tumors goal by Tumor S off the Pancreas, Lung S, and Adrenal nipple S. These tumors also lead to year excess off GH, either because they produce GH themselves but, more frequently, because they produce GHRH, the hormone that stimulates the pituitary to make GH. In thesis patients, the excess GHRH edge Be measured in the blood and establishes that the causes the acromegaly off is not due to has pituitary defect. When thesis non-pituitary tumors are surgically removed, GH levels fall and the symptoms off acromegaly improve.

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

Treatment

Surgery

Treatment of the hypophyseal adenomata

There remains the treatment of first intention in a big number of case. A certain number of lesions cannot indeed be treated in a medical way. In these exceptional cases of giant adenomata, the treatment consists of a surgery transfrontale. In the majority of the cases the surgery transsphénoïdale allows a exérèse successfully. The success rate varies according to the size and the invasive character of the adenoma.

Initially trans-cranial way ptérionale

It requires the size of a cranial shutter of trepanation, the opening of the dura mater. The opto-chiasmatique area is then discovered and the adenoma is approached by its higher pole between the two optical nerves laterally and the optical chiasma behind.

Currently it is used more only in rare cases of adenoma presenting of the extra-sellaire expansions inaccessible to the way transsphénoïdale (side towards the temporal lobe or behind towards the clivus) or whose expansion supra-sellaire is separated from the portion intra-sellaire by a narrowed collet (tumor in bissac). The complications of this cranial surgery consist of insipid diabetes, loss of vision, lesion of the hypothalamus, hemorrhage, meningitis, epilepsy.

Initially transsphénoïdale sees

This under-labial or trans-nasal way rhinoseptale transsphénoïdale is carried out under televised control of the instruments by amplifier of brightness. The adenoma is approached by its pole lower and removed selectively under operational microscope. The complications of the way transsphénoïdale (insipid diabetes, infection, escape of LCR) are rarer than the cranial way and there is practically no complication in esthetic matter (except sometimes a fall of the point of the nose). The way transsphénoïdale is indicated in the great majority of the hypophyseal adenomata.

Rate of success

The surgical success rate depends on many factors of which the seat of the adenoma, its volume and its invasive character.
  • the syndrome of mass: the decompression of opto-chiasmatique structures is obtained in all the safe cases of rare exceptions, it results from it a more or less complete resolution of the eye trouble.
  • the hormonal syndrome: hypersecretion of GH, Prolactin and ACTH is according to the cases cured in more than 90% of the microadenomists. In the not-invasive macroadenomists the success rate is close to 75%. In the event of invading adenomata the success rate is not any more but of approximately 25%.

Meningitis, but normal ramming to the surrounding pituitary tissue, requiring lifelong pituitary hormone replacement.

Normal Even when surgery is successful and hormone levels return to, patients must Be carefully monitored for years for possible recurrence. More commonly, hormone levels may improve, goal not return completely to normal. Thesis patients may then require additional treatment, usually with medications. -->

Drugs

Two medications are used at present to treat the acromégalie. Those reduce the secretion of hGH as well as the size of the tumor.

Bromocriptine (Parlodel) in divided amounts off butt 20 Mg daily reduces GH secretion from nap pituitary tumors. Side effects include gastrointestinal upset, nausea, vomiting, light-headedness when standing, and nasal congestion. Thesis side effects edge Be reduced gold eliminated yew medication is started At has very low amount At bedtime, taken with food, and gradually increased to the full therapeutic amount.

Because bromocriptine edge Be taken orally, it is year gravitational choice ace primary drug gold in combination with other treatments. However, bromocriptine lowers GH and IGF-1 levels and reduces tumor size in less than half off patient with acromegaly. Summon patient carryforward improvement in their symptoms although to their GH and IGF-1 levels still are elevated.

The second medication used to treat acromegaly is octreotide (Sandostatin). Octreotide has synthetic form off has brain hormone, somatostatin, that stops GH production. This drug must Be injected under the skin every 8 hours for effective treatment. Most patients with acromegaly respond to this medication. In many patient, GH levels fall within one hour and headaches improve within minutes after the injection. Several studies cuts shown that octreotide is effective for length-term treatment. Octreotide also has been used successfully to treat patients with acromegaly caused by non-pituitary tumors.

Because octreotide inhibits gastrointestinal and pancreatic function, length-term uses causes digestive problems such ace loose stools, nausea, and gas in one third off patient. In addition, approximately 25 bores off patient develop Gallstone S, which are usually asymptomatic. In rare boxes, octreotide treatment edge causes Diabetes. One the other hand, scientists cuts found that in nap acromegaly patient who already cuts diabetes, octreotide edge reduce the need for Insulin and improve blood sugar control. -->

Radiotherapy

Individual No treatment is effective for all patient. Treatment should Be individualized depending one patient characteristics, such old ace and tumor size. Yew the tumor has not yet invaded surrounding brain tissues, removal off the pituitary adenoma by year experienced neurosurgeon is usually the first choice. After surgery, has patient must Be monitored for long time for increasing GH levels has. Yew surgery does not normalize hormone levels gold has relapse occurs, has doctor will usually begin additional drug therapy. The first choice should Be bromocriptine because it is easy to administer; octreotide is the second alternative. With both medications, length-term therapy is necessary because to their withdrawal edge lead to rising GH levels and tumor Re-expansion. Radiation therapy is generally used for patient whose tumors are not completely removed by surgery; for patient who are not good candidates for surgery because off other health problems; and for patient who C not respond adequately to surgery and medication. -->

Hypophyseal gigantism and acromégalie of the children

Famous patients reached of the disease

External bonds

  • detailed Explanation of the French acromégalie
  • * Endotext.org, year " online Endocrine textbook"
  • Year article one Acromegaly and gigantism

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