Growth hormone deficiency

Growth hormone deficiency (GHD) is characterized by abnormally short height due to lack (or shortage) of growth hormone. It can be congenital (present at birth) or acquired. Most cases are identified in children. Although it is uncommon, growth hormone deficiency may also be diagnosed in adults. Too little growth hormone can cause short stature in children, and changes in muscle mass, cholesterol levels, and bone strength in adults.

Cause

Most of the time, no single clear cause can be identified but several genetic causes of GHD have been described, such as mutations in the to POU1F1/Pit1 , PROP1 GHRH and GH1 genes.

Signs and symptoms

Child

GH deficiency does not usually impair length growth until after the first few months of life. From late in the first year until mid teens, poor growth and/or shortness is the hallmark of childhood GH deficiency. Growth is not as severely affected in GH deficiency as in untreated hypothyroidism, but growth at about half the usual velocity for age is typical. It tends to be accompanied by delayed physical maturation so that bone maturation and puberty may be several years delayed. When severe GH deficiency is present from birth and never treated, adult heights can be as short as 48-65 inches (122–165 cm).

evere GH deficiency in early childhood also results in slower muscular development, so that gross motor milestones such as standing, walking, and jumping may be delayed. Body composition (i.e., the relative amounts of bone, muscle, and fat) is affected in many children with severe deficiency, so that mild to moderate chubbiness is common (though GH deficiency alone rarely causes severe obesity). Some severely GH-deficient children have recognizable, cherubic facial features characterized by maxillary hypoplasia and forehead prominence. Other side effects in children include sparse hair growth and frontal recession, and pili torti and trichorrhexis nodosa are also sometimes present.

Adults

Recognised effects include:

• Increased 5-alpha-reductase
• Reduced sex hormone-binding globulin (SHBG)
• Reduced muscle mass and strength
• Baldness in men
• Reduced bone mass and osteoporosis (Decreased bone density)
• Reduced energy
• Impaired concentration and memory loss
• Increased body fat, particularly around the waistline
• Lipid abnormalities, particularly raised LDL cholesterol
• Increased levels of fibrinogen and plasminogen activator inhibitor
• Cardiac dysfunction, including a thickened intima media
• Lack of well-being
• Depression and anxiety
• Social isolation
• Fibromyalgia syndrome
• Neuromuscular dysfunction
• Central adiposity
• Decreased muscle mass
• Insulin resistance
• Accelerated atherogenesis
• Prothrombotic state
• Decreased sweating and thermoregulation.

Diagnosis

Diagnosis involves blood tests to measure growth hormone levels.This makes simple measurement of GHin a single blood sample useless for detecting deficiency. Physicians therefore use a combination of indirect and direct criteria in assessing GHD, including:

• Auxologic criteria (defined by body measurements)
• Indirect hormonal criteria (IGF levels from a single blood sample)
• Direct hormonal criteria (measurement of GH in multiple blood samples to determine secretory patterns or responses to provocative testing), in particular:
  • Subnormal frequency and amplitude of GH secretory peaks when sampled over several hours
  • Subnormal GH secretion in response to at least two provocative stimuli
  • Increased IGF1 levels after a few days of GH treatment
• Response to GH treatment
• Corroborative evidence of pituitary dysfunction

Classification

Growth hormone deficiency can be congenital or acquired in childhood or adult life. It can be partial or complete. It is usually permanent, but sometimes transient. It may be an isolated deficiency or occur in association with deficiencies of other pituitary hormones.

The term hypopituitarism is often used interchangeably with GH deficiency but more often denotes GH deficiency plus deficiency of at least one other anterior pituitary hormone. When GH deficiency (usually with other anterior pituitary deficiencies) is associated with posterior pituitary hormone deficiency (usually diabetes insipidus), the condition is termed panhypopituitarism.

Risk factors

Adult-onset GHD is commonly due to pituitary tumours and their treatment or to cranial irradiation. congenital diseases such as Prader-Willi syndrome, Turner syndromeare an important cause of growth failure in children with short stature. intracranial tumors in or near the sella turcica, especially craniopharyngioma Damage to the pituitary from radiation therapy to the head (e.g. for leukemia or brain tumors), from surgery, from trauma, or from intracranial disease (e.g. hydrocephalus).

Treatment

GH deficiency is treated by replacing GH with daily injections under the skin or into muscle. Until 1985, growth hormone for treatment was obtained by extraction from human pituitary glands collected at autopsy. Since 1985, recombinant human growth hormone (rHGH) is a recombinant form of human GH produced by genetically engineered bacteria, manufactured by recombinant DNA technology.

The medication(s) listed below have been approved by the Food and Drug Administration (FDA) as orphan products for treatment of this condition.

• Somatropin (r-DNA) for injection (Brand name: Genotropin) For long-term treatment of growth failure in children born small for gestational age who fail to manifest catch-up growth by two years of age. Also for the treatment of adults with growth hormone deficiency.
• Somatropin (r-DNA) for injection (Brand name: Humatrope)For the long-term treatment of children who have growth failure due to inadequate secretion of normal endogenous growth hormone.
• Macimorelin acetate (Brand name: Macrelin) macimorelin acetate (Macrelin) was approved for the diagnosis of adult growth hormone deficiency (AGHD).
• Somatropin (r-DNA) for injection (Brand name: Norditropin)Long-term treatment of children who have growth failure due to inadequate secretion of endogenous growth hormone.

Somatropin (r-DNA) for injection (Brand name: Nutropin AQ)For use in the long-term treatment of children who have growth failure due to a lack of adequate endogenous growth hormone secretion. Also for treatment of children with growth failure associated with chronic renal insufficiency and as replacement therapy for growth hormone deficiency in adults after epiphyseal closure.

• Somatropin (r-DNA) for injection (Brand name: Saizen)For the long term treatment of children with growth failure due to inadequate secretion of endogenous growth hormone. Also for the treatment of adults with GHD that started as a child or as an adult.

This template is no longer used; please see Template:Endocrine pathology for a suitable replacement

NIH genetic and rare disease info

• NIH info on Growth hormone deficiency

Growth hormone deficiency is a rare disease.

Growth hormone deficiency Resources
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