Pituitary dwarfism refers to a condition where the body length is below two standard deviations of normal children or below the third percentile of the same age group due to dysfunction of the hypothalamus or anterior pituitary, resulting in insufficient growth hormone. Growth hormone is secreted by acidophilic cells in the anterior pituitary under the influence of hypothalamic growth hormone-releasing hormone. It directly affects tissues, influencing their growth and metabolism, and also stimulates the production of somatomedin, which promotes bone growth, protein synthesis in non-bone tissues, and cell proliferation. Therefore, any disruption in the growth hormone-releasing hormone—growth hormone—somatomedin pathway can lead to pituitary dwarfism. This condition can be classified into: (1) idiopathic; (2) secondary (caused by tumors, trauma, surgery, inflammation, cellular infiltration, or X-ray irradiation in the pituitary or hypothalamic region); (3) hereditary.

bubble_chart Clinical Manifestations

1. Growth retardation: Normal at birth, growth slows down after 1 to 2 years of age, but the upper-to-lower segment ratio remains normal, with a proportionate body shape.
2. Delayed bone maturation: Tooth development is often 2 years behind the actual age, and bone age is also delayed.
3. Delayed puberty.
4. Normal intelligence.

bubble_chart Auxiliary Examination

1. Delayed bone age: Determined based on the number and morphology of ossification centers and the developmental level of each metacarpal and phalangeal bone. Generally delayed by 2 years.
2. Take anteroposterior and lateral X-rays of the skull and sella turcica to assess for intracranial lesions and the developmental status of the sella turcica.
3. Serum growth hormone concentration measurement: Higher in children than adults, 30μg/L at birth, then declines, usually around 5μg/L at rest. Secretion is pulsatile and influenced by various factors, so a single specimen measurement often lacks diagnostic value. Clinically, certain stimulation tests are commonly used for detection.

bubble_chart Diagnosis

Diagnostic Criteria

1. Height is more than 2 standard deviations below the mean for normal children of the same ethnicity, age, and sex.
2. Annual height growth<4cm。
3. Bone age is delayed by 2 years.
4. Generalized proportional short stature with normal intelligence.
5. Peak growth hormone level in pharmacological stimulation test<5μg/L。

bubble_chart Treatment Measures

The best treatment for pituitary dwarfism is growth hormone replacement therapy. In recent years, DNA recombinant preparations have become available. The dosage is 0.1–0.7 U/kg per week via intramuscular or subcutaneous injection. Some protocols use a daily subcutaneous injection of 0.1 U/kg. The earlier the treatment begins, the better the therapeutic effect. If the above medication is unavailable, anabolic steroids such as nandrolone phenylpropionate at 1 mg/kg every two weeks can be used. For bone age over 12 years, human chorionic gonadotropin (HCG) can be added at 1000 U per dose, twice weekly, in 4–6 week courses to promote growth and the onset of puberty.

bubble_chart Differentiation

For individuals with normal body proportions but short stature, the following issues should be distinguished:

1. Familial short stature: closely related to short parents.
2. Constitutional delay of puberty: can be delayed until age 18, with a growth spurt and sexual development occurring after puberty begins. For difficult-to-diagnose cases, a chorionic gonadotropin stimulation test can be performed when bone age reaches 12 years. In this condition, testosterone increases after injection, while there is no response in primary gonadal dysfunction, and a normal response in pituitary dwarfism.
3. Low birth weight infants: may experience persistent growth retardation.
4. Severe chronic systemic diseases.
5. Psychosocial dwarfism: caused by environmental and psychological factors.
6. Ovarian dysgenesis (Turner syndrome): in addition to short stature, features include neck webbing, cubitus valgus, absence of secondary sexual characteristics, and primary amenorrhea. Chromosomal testing can confirm the diagnosis (XO).