Growth Hormone Deficiency
المؤلف:
Marcello Ciaccio
المصدر:
Clinical and Laboratory Medicine Textbook 2021
الجزء والصفحة:
p319-320
2025-09-11
267
Growth Hormone Deficiency (GHD) is a clinical condition caused by pathological GH deficiency and, therefore, characterized by reduced stature growth in children and increased body fat and reduced muscle mass in adults; adults with GH deficiency often complain of lack of energy and difficulty concentrating. GH deficiency can present in very variable forms with a clinical picture conditioned by the severity of the hormonal deficit (isolated or associated with other pituitary tropins) and by the age of onset. It is essential to identify GHD early, especially in children, as treatment with recombinant human GH is highly effective in inducing an increase in final height.
GH Deficiency in Children
The deficiency can be diagnosed at any age, but since infants with GHD have an average birth weight and length, the slowdown in growth rate is usually noticed relatively late. Characteristic signs of the deficit, in addition to short stature, are infantile facial features, delayed teething, small penis (micropenis), and increased fat in the subcutaneous tissue deposited on the hips and abdomen.
GHD can be congenital or acquired. Congenital causes include structural malformations of the brain, for example, abnormal development of the hypothalamus or pituitary gland, and genetic mutations resulting in alterations in the synthesis or function of GH or the receptor for GHRH or peripheral tissue insensitivity due to structural defects in the GH receptor or intracellular signal; in this case (peripheral insensitivity to GH), we speak of a syndrome known as Laron syndrome characterized by normal or elevated GH levels associated with reduced IGF1 values and, in some cases, reduced levels of GH-binding proteins (Growth Hormone–Binding Proteins, GHBP).
Acquired GH deficiency can be due to various causes. The most frequent are benign tumors of the pituitary gland (pituitary adenomas), which, as they grow, can damage the remaining gland; less frequent causes include cranial irradiation, brain trauma, and central nervous system infections and inflammatory conditions (e.g., sarcoidosis). GH deficiency can occur in isolation or combination. In the latter case, GH deficiency is associated with the deficiency of one or more pituitary tropins and is generally due to mutations of transcription factors such as Pit-1 and Prop-1, which regulate the differentiation of somatotropic cells of the adenohypophysis.
GH Deficiency in Adults
Growth hormone deficiency in adults is generally caused by hypothalamic or pituitary damage, usually secondary to pituitary surgery, tumors, radiation treatment, or a developmental age deficiency. Acquired pituitary insufficiency has a defined framework of functional deficit in which loss of adequate GH reserve precedes other tropin deficits (GH, LH/ FSH, TSH, and ACTH).
GHD in adults is not defined by a characteristic clinical picture. However, it presents nonspecific signs and symptoms, including an increase in body fat, especially visceral, with an increase in the waist-to-hip ratio, a reduction in muscle mass, a reduction in bone density (osteopenia and osteo porosis) with an increased risk of fractures, reduced performance during physical activity, and finally, alterations in cardiovascular function. Thus, GHD in adults can mani fest itself subtly and may not be easily recognizable on clinical observation alone. GHD in adults must be suspected in the presence of specific conditions.
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