Acromegaly (Greek. akros – extreme and megas – large) is a severe neuroendocrine disease caused by hyperproduction of growth hormone (somatotropin; somatotropic hormone; STH). Pituitary adenoma (somatotrophic adenoma) is a benign tumor that produces isolated somatotropin. Quite often, simultaneous hyperproduction of somatotropin and prolactin (prolactin somatotropic adenoma; mammosomatotropic adenoma) occurs in the tumor.
Hyperproduction of growth hormone causes an increased secretion of growth factors (somatomedins), mainly insulin growth factor (IGF-1; somatomedin C), which are produced in the liver. STH also stimulates the production of growth factors in various organs (bones, cartilages, etc.)
If the disease occurs in adolescence, when there is no calcification of the bone epiphyses, the skeleton bones grow in length – this clinical syndrome is called gigantism.
• gross changes in appearance (enlargement of superciliary ridges, nose, lips, tongue, thickening and folding of the skin, diastema – expansion of interdental spaces, prognathism – lower jaw protrusion, an increase in the size of the hands and feet);
• a low coarse voice (as a result of thickening of the vocal cords and the expansion of the paranasal sinuses);
• pain in the joints and spine, associated with their destabilization and the development of arthropathy;
• villous wart growths;
• hyperpigmentation of the skin within natural folds;
• hirsutism (male-type overgrowth of terminal hair) in women;
• enlargement of the thyroid gland (with possible nodulation);
• development of insulin-resistant diabetes mellitus;
• cardiovascular pathology (cardiomegaly, arterial hypertension, myocardial dystrophy and, as a consequence, coronary insufficiency, which may cause death);
• respiratory system disorders (kyphoscoliosis-associated restrictive pulmonary diseases; obstructive night apnea, associated with an increased tongue and epiglottis);
• development of carpal tunnel syndrome (compression of the median nerve by altered soft tissues in the wrist, manifested by a decrease in the sensitivity of the fingers).
• rapid fatigue, weakness, reduced working ability.
As the tumor increases in size, it squeezes the surrounding healthy pituitary cells, interfering thereby their proper functioning, and causing following symptoms:
• headaches, poorly released by analgesics (with possible tearing, photophobia) and, depending on extrasellar growth of the tumor, various neurological manifestations may appear.
• decreased libido and potency in men;
• menstrual disorders and infertility in women;
Mortality of patients with acromegaly who did not receive adequate therapy:
• about 50% of patients die before 50 years;
• about 60% of mortality accounted for cardiovascular complications;
• about 25% – for pulmonary respiratory complications;
• about 15% – for malignant neoplasms, mainly of the gastrointestinal tract;
Differential diagnosis of acromegaly
• The extrapituitary STH-secreting tumor – neoplasms of the pancreas, lungs, mediastinum, ovaries, etc.;
• Increased secretion of GHRH (Growth-hormone-releasing hormone; somatoliberin) – both as a tumor (hypothalamic hamartoma; gangliocytoma; tumors of the lung, pancreas, etc.) and as a result of inflammation in the central nervous system (arachnoiditis, etc.);
• MEN-1-syndrome (multiple endocrine neoplasia syndrome) represents a mandatory presence, in addition to hormonally active pituitary adenoma, a hormonally active tumor of a different location (pancreas; parathyroid glands; lung tumor, etc.).
• Also, some symptoms similar to acromegaly can occur in the following diseases: hypothyroidism, pachydermoperiostosis, Paget’s disease, McCune–Albright syndrome, acromegaloidism.
The method of treatment is selected individually for each specific case. The advantage of the surgical treatment of acromegaly (removal of pituitary adenoma – somatotropic adenoma) is the rapid decrease in growth hormone and the elimination of tumor compression on nearby structures. Another methods distinguished are conservative (drug treatment) and radiation therapy.