Chủ Nhật, 12 tháng 1, 2014

Gigantism

Gigantism Gigantism is a disorder caused by excess of insulin like growth factor in the childhood during the stage when the epiphyseal plates are kept open. This term is commonly referred to any excess or abnormal growth in height above the standard norms related to the individual’s age and sex.


Acromegaly and Gigantism :


Acromegaly and gigantism are one and the same and both are caused by excess of insulin like growth factor in the body. But in acromegaly this growth factor is present in excess after the fusion of cartilage plates in adulthood. Both these disorders are placed under the heading of IGF-1 hyper-secretion. In both the cases there are manifestations of excessive growth with respect to height due to excessive bone growth.


In gigantism excess of growth hormone is secreted by the pituitary gland which continues its production even during adulthood. This causes heightened development of bones of face, hands and feet thus projecting giant like structure. If not treated in time, acromegaly can cause serious complications in future. Acromegaly disorder occurs after the normal bone growth stops and it is mostly present in adulthood. But gigantism is observed in childhood when the bony plates have not closed properly. Both these disorders are very rare and occur in 50 out of one million people. The characteristic features of gigantism are observed during puberty but in rare cases it is seen in young children also.


Causes :


The major cause of gigantism is excess of hormone secretion by the pituitary gland. Pituitary gland is vital for normal functioning of many organs in your body and it controls important metabolism like growth and reproductive function. Pituitary gland receives signal from the hypothalamus of the brain to secrete or stop growth hormone and thus the discharge of hormone stays in control. But under certain circumstances, pituitary gland automatically produces excess of growth hormone which in turn directs too much of production of insulin like growth factor (IGF) leading to excess of bone development causing gigantism.


Pituitary tumor (non-cancerous) is the main reason for producing excess of growth hormones in adult. Other causes of gigantism include Camey complex, multiple endocrine neoplasia type 1, and McCune Albright syndrome. In rare cases, tumors found in other parts of the body like pancreas or lungs can cause excess of growth hormone leading to gigantism.


Symptoms :


Gigantism leads to excessive growth of bones causing enlarged hands and feet and enlarged facial features. The bones, muscles and all other organs of the child will grow excessively. Nose, forehead and jaw line gets enlarged and the teeth will be widely spaced giving ugly appearance. Children with this disorder can no longer use the same shoes for few months since their hands and feet will grow progressively.


Since the symptoms of acromegaly or gigantism causes gradual changes it is not possible to detect serious changes by the parents. Only by comparing the photos they can see the difference. Some of the other symptoms of gigantism are excess of sweating, excess of body hair, high blood pressure, cardiovascular disease, osteoarthritis, diabetes, increased calcium content and increased gallstones. They may also suffer from severe headaches and joint pain due to swelling and enlargement of joints. Skin tags or polyps are present in excess on their skin. Some children will have noticeable voice change due to enlargement of vocal cord.


Adults with this problem can have problems in vision, erectile dysfunction, irregular menstrual cycle, tingling sensation in hands and feet, and problems in kidneys and spleen. An early diagnosis of the disorder is absolutely necessary and undue delay can cause serious complications.


Diagnoses :


The doctor can detect the symptoms of gigantism by physical examination of the child. He will check for enlargement of hands, feet and other facial features. He may request for MRI or CT scan for detecting the tumor size. He may suggest for taking blood sample (on fasting overnight) for measuring the levels of growth hormone and IGF. Growth hormone suppression test is the right tool for verifying acromegaly.


Treatment :


The ultimate aim of the treatment is to reduce the secretion of growth hormone. Surgery is the best option available for removing pituitary tumors. Medications are given for lowering the production or blocking the level of growth hormone factor. Somatostatin agents like octreotide and lanreotide are given for stabilizing the somatostatin hormone. To begin with this drug is given subcutaneously to check its tolerance.


Gradually the dosage is increased for producing the desired effect. Dopamine agents like cabergoline and parlodel are given as oral pills. These drugs can produce adverse effects like changing the individual’s behavior. Somavert is given as growth hormone antagonist for blocking the level of growth hormone level on the tissues. Most of the symptoms of gigantism can be managed by this medication. Radiation is the ideal choice for treating pituitary tumor which would gradually slow down the tumor causing cells.


Either radiation is given in the form of conventional method for years together or in the form of surgery. Radiosurgery is done for destroying the tumor cells and for controlling the levels of IGF-1. Whatever may be the treatment method, it is necessary to follow-up continuously with your doctor for getting the best results. Further children with gigantism and diabetes mellitus should be on diet schedule for controlling the blood sugar level.


Prevention :


Gigantism and acromegaly cannot be prevented. In children with gigantism if the liner growth is not treated in early stages, it can lead to acromegaly and serious complications like heart disease or cancer.


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