PANCE Blueprint Endocrinology (7%)

Pituitary dwarfism (GH deficiency)

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 4th percentile for height and 95th percentile for head circumference. He demonstrates normal intelligence and is able to 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 IGF1.

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 an unusually small stature (below average height).

  • Growth hormone secretion can be decreased in adults, resulting in increased fat and decreased muscle mass, but this will not affect bone growth.

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

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

GH deficiency causes short stature; numerous other manifestations may be present depending on the cause

Serial measurements > 2.5 deviations below the normal mean should prompt growth hormone evaluation. Rule out other causes. Diagnosis can be confirmed by low levels of insulin-like growth factor-1 and insulin-like growth factor binding protein-3.

Labs: ↓ GH, ↓ IGF1

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

If dwarfism is due to decreased human growth hormone, and not due to a primary skeletal disorder, the child can be treated with human growth hormone treatments to try and stimulate normal growth.

Surgery may be necessary to remove a pituitary adenoma if that is the cause of the dwarfism.

  • Complications: Poorly developed organs including the heart, impaired sexual maturation, kyphosis, arthritis, sleep apnea, spinal stenosis, motor delays, ear infections, hearing loss.
  • Children with short stature and documented GH deficiency should receive recombinant GH; other manifestations of hypopituitarism are treated as needed

Pituitary dwarfism

Question 1
What is the most common cause of short stature in children?
A
familial short stature
B
chromosomal abnormality
C
constitutional delay of growth
D
hypothyroidism
E
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?
A
bone age is normal in both familial short stature and constitutional delay of growth
B
bone age is normal in familial short stature and delayed in constitutional delay of growth
C
bone age is normal in constitutional delay of growth and delayed in growth hormone deficiency
D
bone age is delayed in both familial short stature and short stature caused by hypothyroidism
E
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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