Acromegaly is a hormonal disorder which occurs due to the overproduction of growth hormone by the pituitary gland. The abnormal secretion of growth hormone occurs generally in adulthood and is evident with unusual increase in bone size resulting in gigantic hands, feet and face. Acromegaly is found in middle-aged adults and increase growth hormone levels in children are often associated with gigantism. In children, abnormal growth hormone secretion is identified with exaggerated bone growth and rapid increase in height. Acromegaly is a rare disease condition and physical changes are gradual which makes this disease difficult to identify for years. It is also alarming that acromegaly needs to be treated promptly and identified immediately, as it is a life threatening condition. Timely treatment of acromegaly could reduce the risk of complications considerably and also manage the symptoms of acromegaly i.e. enlargement of physical features. Common signs of acromegaly, which should be noticed immediately, are rapid increase in growth of hands and feet. People who are suffering from acromegaly might observe that their ring size and shoe size are difficult to find (Caron, Brue, Raverot et al. 2018).
Progressive stages of acromegaly result in changes in features of face, protrusion of lower jaw, thickened lips and enlarged nose. Acromegaly is a slowly progressing disease and its symptoms are apparent after several years of having the disease. The early signs of the disease are oily and thickened skin, excessive sweating and body odor, fatigue, muscle weakness, tissue outgrowths, deep voice due to enlarged vocal cords, headache, enlarged tongue, impaired vision, enlarged organs, and increased chest size. The genital and sex hormone changes in women due to acromegaly cause menstrual cycle irregularities, whereas, hormonal changes in men cause erectile dysfunction (Caron, Brue, Raverot et al. 2018).
The pathophysiology of acromegaly is due to overproduction of growth hormone (GH) from the pituitary gland situated at the base of the brain. This pituitary gland is responsible for the production of a variety of hormones and GH (Growth Hormone) is one of them responsible for adequate physical growth. The secretion of GH activates the liver enzymes for producing insulin-like growth factor-I (IGF-I). IGF-I is responsible for bone and tissue growth and excessive secretion of this hormone results in abnormal growth of skeleton and soft tissues (Katznelson, Laws, Melmed, Molitch, Murad, Utz & Wass, 2014).
The most common cause of excessive GH production in middle-aged adults is a pituitary tumor. Acromegaly is generally associated with the development of a non-cancerous adenoma in the pituitary gland. This benign tumor secretes GH in excessive amounts causing headaches and impaired vision initially. It is also observed that some patients of acromegaly are also diagnosed with non-pituitary tumors. The tumors which might be responsible for acromegaly are often found in the lungs, adrenal gland (s) and pancreas. In non-pituitary tumors, acromegaly is often associated with increased stimulation of growth hormone releasing hormone (GHRH) which in-turn is responsible for excessive secretion of GH.
Acromegaly could cause severe complications if not diagnosed on time and these complications include cardiovascular disease, cardiomyopathy, hypertension, Diabetes mellitus, and goiter. Carpel tunnel syndrome, spinal cord compression and uterine fibroids are also some important medical conditions associated with uncontrolled acromegaly (Katznelson et al. 2014).
Diagnostic examination of acromegaly can be performed through measurement of GH and IGF-I levels. Elevated levels of these hormones are the early signs of the disease. Later, the disease is also apparent in physical growth abnormalities. Another important diagnostic test is the Growth Hormone suppression test. This test verifies GH levels in the blood after giving a preparation of glucose to the patient. In a “normal” patient, glucose ingestion depresses the GH levels in the blood. However, a patient who is suffering from acromegaly will have impaired glucose metabolism and the GH levels in these patients will remain consistently high.
Apart from laboratory tests, magnetic resonance imaging (MRI) is also recommended in patients showing symptoms of acromegaly. The brain MRI helps in determining the location and size of pituitary or adrenal tumors (Van der Lely, 2017).
The treatment protocol for patients diagnosed with acromegaly shall be focused on reducing the abnormal effects of the tumor and for managing the disease symptoms. Endoscopic transnasal transsphenoidal surgery is a good option for these patients. In this surgical method, the pituitary tumor is removed which normalizes the production of GH and relieves the symptoms of the disease. If for some reason, the surgeon is unable to remove the pituitary tumor completely; radiation treatment is also provided in conjunction. Conventional radiation therapy is given over a period of four to six weeks and its impact is not readily visualized. Proton beam therapy is another high dose radiation which is provided in fractions and the frequency of treatment is less than conventional radiation. Stereotactic radiosurgery is given as a single high dose and is effective in bringing the GH levels to normal levels in a period of 3-5 years (Van der Lely, 2017).
Pharmacological therapy of acromegaly is performed by giving drugs which block the action of GH. These drugs include somatostatin analogue, dopamine agonist, and growth hormone agonist. Example of Somatostatin analogues include octreotide and lanreotide which are the synthetic versions of somatostatin hormone secreted from the brain. These hormone analogues interfere with the excessive secretion of GH and helps in the decline of GH blood levels. Octreotide is given subcutaneously for short-term effect and is administered intra-muscularly in the buttocks to produce a long-term effect. Lanreotide produces optimum effect when given subcutaneously once a month. Dopamine agonists such as cabergoline and bromocriptine are administered orally. The mechanism of action of dopamine agonists is to lower the blood levels of GH and IGF-I. Another medication category is growth hormone antagonist for e.g. pegvisomant which blocks the effect of GH on the tissues and organs. Growth hormone antagonists are given to those patients who did not get a positive response from other treatments. These medications normalize the IGF-I levels and relieve symptoms of acromegaly. These drugs are also effective in decreasing the size of the tumor thereby managing the symptoms of physical overgrowth. After initial treatment of acromegaly, periodic monitoring of patient’s growth hormone levels is a must (Grasso, Auriemma, Pivonello & Colao, 2017).
Caron, P., Brue, T., Raverot, G., Tabarin, A., Cailleux, A., Delemer, B., … & Chanson, P. (2018). Signs and symptoms of acromegaly at diagnosis: the physician’s and the patient’s perspectives in the ACRO-POLIS study. Endocrine, 1-10.
Grasso, L. F., Auriemma, R. S., Pivonello, R., & Colao, A. (2017). Somatostatin analogs, cabergoline and pegvisomant: comparing the efficacy of medical treatment for acromegaly. Expert review of endocrinology & metabolism, 12(1), 73-85.
Katznelson, L., Laws Jr, E. R., Melmed, S., Molitch, M. E., Murad, M. H., Utz, A., & Wass, J. A. (2014). Acromegaly: an endocrine society clinical practice guideline. The Journal of Clinical Endocrinology & Metabolism, 99(11), 3933-3951.
Van der Lely, A. J. (2017). The states of the art management of acromegaly: From diagnosis to treatment and 10 years follow up. Problemy Endokrinologii, 63(1).
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