Growth Hormone Deficiency
- Insufficient production of growth hormone (GH) in adults or children caused by problems arising in the pituitary gland and/or hypothalamus
- GH is produced by somatotroph cells of the anterior pituitary gland, which is stimulated by growth hormone–releasing hormone (GHRH) and inhibited by somatostatin from the hypothalamus.
- GH, also called somatotropin, is a polypeptide hormone that stimulates growth and cell reproduction.
- Hypopituitarism is a deficiency in at least one pituitary hormone, including GH.
- Panhypopituitarism is a deficiency in all the hormones produced in the pituitary gland.
- System(s) affected: endocrine, musculoskeletal, cardiovascular, psychological
- Synonym(s) and keywords: hypopituitarism; familial short stature; short height; growth pattern; pituitary dwarfism; acquired GHD; isolated GHD; congenital GHD; panhypopituitarism
- Most common cause of GHD in children is idiopathic.
- Most common cause of GHD in adults is a pituitary adenoma or treatment of the adenoma with surgery or radiotherapy:
- 76% of patients with GHD had a pituitary tumor.
- 13% had an extrapituitary tumor.
- 8% idiopathic cause
- 1% had sarcoidosis.
- 0.5% had Sheehan syndrome.
- In children, isolated GHD is reported to affect 1 in 4,000.
- Adult-onset idiopathic GHD is extremely rare.
Etiology and Pathophysiology
- GHD is caused by a genetic or acquired absence or decline in production of GH.
- Hypothalamus secretes GHRH, which stimulates the pituitary to secrete GH.
- Somatostatin is secreted by the hypothalamus to inhibit GH secretion.
- When GH pulses are secreted into the blood, then insulin-like growth factor (IGF)-1 is released from the liver.
- GHD may result from disruption of the GH axis—in the higher brain, the hypothalamus, or the pituitary gland (1)[C].
- Genetic (see “Genetics”)
- Structural brain defects
- Agenesis of corpus callosum
- Septo-optic dysplasia
- Empty sella syndrome
- Arachnoid cyst
- Associated midline facial defects
- Single central incisor
- Cleft lip/palate
- CNS infection
- Tumors of hypothalamus or pituitary
- Pituitary adenoma
- Rathke cleft cyst
- Metastatic tumor
- Infiltrative/granulomatous disease
- Langerhans cell histiocytosis
- Cranial irradiation
- Pituitary infarction
- Hemochromatosis (rare)
A variety of congenital genetic causes of GHD:
- Transcription factor defects (POU1F1/PIT-1, PROP-1, LHX3/4, HESX-1, SOX-3, and PITX-2)
- GHRH-receptor gene defects
- GH secretagogue (GHS) receptor gene defects
- GH receptor/postreceptor defects
- Prader-Willi syndrome
- Deletion and mutation of GH-1
Commonly Associated Conditions
- Pituitary adenoma (particularly macroadenoma)
- Sheehan syndrome
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