PANCE Blueprint Endocrinology (7%)

Pituitary dwarfism (GH deficiency) Lecture

Patient will present as → a 3-year-old male who is brought to your office by his mother who is concerned that he is not growing appropriately. Physical examination is notable for frontal bossing and shortened upper and lower extremities. His axial skeleton appears normal. He is at the fourth percentile for height and 95th percentile for head circumference. He demonstrates normal intelligence and can speak in three-word sentences. He first sat up without support at twelve months and started walking at 24 months. Labs reveal decreased GH and decreased IGF-1.

Pituitary dwarfism, or growth hormone deficiency, is a condition in which the pituitary gland does not make enough growth hormone. This results in a child's slow growth pattern and unusually small stature (below average height)

  • Growth hormone secretion can be decreased in adults, resulting in lower bone density and decreased muscle mass, but this will not affect bone growth
  • The primary manifestations of growth hormone deficiency in infancy are hypoglycemia and micropenis
  • In children, bone growth is typically delayed relative to chronological age due to an under-stimulation of osteoblasts which can result in short stature

Growth hormone (GH) deficiency can occur in isolation or in association with generalized hypopituitarism

  • Causes include congenital (including genetic) disorders and several acquired disorders of the hypothalamus and/or pituitary

Serial measurements > 2.5 deviations below the normal mean should prompt growth hormone evaluation

  • Diagnosis can be confirmed by low levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3
  • Labs: ↓ GH, ↓ IGF 1

BONE AGE: The primary symptom of pituitary dwarfism is lack of height. Therefore, a change in the individual's growth habits will help lead to a diagnosis. X-ray the child's hand to determine the child's bone age by comparing this to the child's actual chronological age.

  • The bone age in affected children is usually two years or more behind the chronological age. This means that if a child is ten years old, his or her bones will look like they are those of an eight-year-old child. The levels of growth hormone and somatomedin C must also be measured with blood tests.

CT or MRI of the brain to evaluate for cause

Growth hormone deficiency can be treated with subcutaneous injections of recombinant human growth hormone to try and stimulate normal growth

  • Surgery may be necessary to remove a pituitary adenoma if that is the cause of dwarfism
  • Other manifestations of hypopituitarism are treated as needed
  • Complications: Poorly developed organs including the heart, impaired sexual maturation, kyphosis, arthritis, sleep apnea, spinal stenosis, motor delays, ear infections, hearing loss

osmosis Osmosis
Question 1
What is the most common cause of short stature in children?
familial short stature
chromosomal abnormality
constitutional delay of growth
pituitary dwarfism
Question 1 Explanation: 
The most common cause of short stature in children is short parents. When a short child who is growing at a normal rate and has a normal bone age is found to have a strong family history of short stature, familial short stature is the most likely cause. Other causes of short stature include constitutional delay of growth, chromosomal abnormalities, intrauterine growth restriction, chronic diseases such as renal disease or inflammatory bowel disease, hypothyroidism, adrenal hyperplasia, growth hormone deficiency or resistance, psychosocial dwarfism, and idiopathic short stature.
Question 2
Bone age can sometimes be used to differentiate certain causes of short stature in children. With respect to bone age, which of the following statements is true?
bone age is normal in both familial short stature and constitutional delay of growth
bone age is normal in familial short stature and delayed in constitutional delay of growth
bone age is normal in constitutional delay of growth and delayed in growth hormone deficiency
bone age is delayed in both familial short stature and short stature caused by hypothyroidism
bone age is variable and cannot be used to differentiate familial short stature and constitutional delay
Question 2 Explanation: 
Bone age determination can distinguish between the two most common causes of short stature: familial short stature and constitutional delay of growth. Children with familial short stature have normal bone ages. Constitutional delay of growth, which is really a delay in reaching ultimate height and sexual maturation, is manifested with delayed bone age and delayed sexual maturation. Hypothyroidism and growth hormone deficiency usually are manifested with a delayed bone age.
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References: Merck Manual · UpToDate

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