Growth hormone excess produces acromegaly if it happens during adulthood.
Suspect when manifestations characteristic of acromegaly are present. These include acromegalic facies (prominent orbital ridges, large nose, prominent lower jaw and thickening of the lips), thick skin, enlargement of the hand and foot, visceromegaly, dorsal kyphosis and macroglossia, carpal tunnel syndrome, hypertension and cardiomyopathy in addition to an increased incidence of ischemic heart disease. Endocrinal manifestations include diabetes, galactorrhoea, menstrual irregularities. Acromegaly is sometimes very difficult to diagnose as the manifestations evolve very gradually.
Once suspected diagnostic investigations include glucose tolerance test and insulin-like growth factor-1 (IGF-1, somatomedin C) assays.
1. Glucose tolerance test: Normally growth hormone is suppressed after oral intake of 50mg of glucose due to inhibition of GHRH secretion. In cases of acromegaly growth hormone levels fail to suppress or may even rise.
2. insulin-like growth factor-1 (IGF-1, somatomedin C) assays are always elevated in acromegaly and do not fluctuate like growth hormone levels.
Treatment is mainly surgical (transfenoidal adenectomy or hypophysectomy of the acidophil adenoma is the treatment of choice if the case is urgent and accompanied by complications such as visual field defects.
Bromocriptine paradoxically leads to a significant reduction in growth hormone levels. Cabergonline is another dopaminergic agent used to reduce growth hormone levels in gigantism.
Octreotide is a synthetic somatostatin analogue which is more effective than bromocryptine.
External radiotherapy is an option in treating acidophil adenomas.
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