Hypersomatotropinemia, hyposomatotropinemia and hyperprolactinemia - etiology, pathogenesis, and clinical manifestations
Hypersomatotropinemia
- Condition characterized by excess secretion of growth hormone (GH) (also called somatotropin).
Etiology
- Pituitary adenoma (GH-secreting, called somatotroph adenoma) → most common cause.
- Ectopic GH or growth hormone- releasing hormone (GHRH) secretion (rare).
Pathogenesis
- Excess GH → stimulates liver and other tissues to produce insulin-like growth factor 1 (IGF-1).
- IGF- 1 mediates many growth- promoting effects.
- Leads to overgrowth of bones and soft tissues.
Clinical manifestations
In children (before epiphyseal closure)
- Gigantism:
- Excessive linear growth.
- Extremely tall stature.
In adults (after epiphyseal closure)
Acromegaly:
- Enlargement of hands and feet (spade-like hands, increased shoe/ glove size).
- Coarse facial features (enlarged nose, jaw, frontal bossing).
- Prognathism (forward protrusion of jaw).
- Thickened skin.
- Organomegaly (heart, liver).
- Metabolic disturbances: insulin resistance → diabetes mellitus.
- Cardiovascular complications: hypertension, cardiomyopathy.
Hyposomatotropinemia
Condition of deficient growth hormone secretion.
Etiology
Congenital GH deficiency (mutations affecting GH gene or GHRH receptor).
Acquired causes:
- Pituitary tumors compressing somatotrophs.
- Trauma, irradiation, inflammation, or surgery involving hypothalamus or pituitary.
Pathogenesis
Decreased GH → reduced IGF-1 production → impaired stimulation of bone and tissue growth.