What Is Pituitary Dwarfism?

Introduction

Pituitary dwarfism, also called growth hormone deficiency, is a medical condition wherein the pituitary gland does not produce sufficient amounts of growth hormone. This deficiency often results in children’s slow growth or short stature.

An adult with pituitary dwarfism has an average height of 4 feet 10 inches or less. The terms short stature, little person, or little people are usually preferred when describing people with dwarfism instead of dwarf and midget, which are totally unacceptable terms.

Pituitary dwarfism can be due to many different medical conditions. However, there are two main types of the condition. They are:

• Disproportionate Dwarfism – As the term suggests, the condition is characterized by having disproportionate parts of the body. It is also the most common type of dwarfism. An example would be achondroplasia, which is a genetic bone growth disorder characterized by short stature with short limbs, but with a normal-sized torso. In some people with this disorder, their head may be disproportionately larger than people without dwarfism. The disorders that cause disproportionate dwarfism usually impair normal bone development.

• Proportionate Dwarfism – This type of dwarfism is characterized by a proportionate head, limbs, and trunk, but usually smaller when compared to average-sized people. Proportionate dwarfism is a usually a result of a hormone deficiency. Treatment can be done through hormone injections in growing children. Children born with this type of dwarfism may be able to reach close to an average height when treated early on.

Symptoms

Aside from short stature, the signs and symptoms of pituitary dwarfism usually vary through the spectrum of disorders.

Disproportionate Dwarfism

People with disproportionate dwarfism often have a normal intellectual functioning, except in rare cases, which are usually a result of secondary factors, such as hydrocephalus (excessive fluid accumulation in the brain).

Achondroplasia is a disorder that causes disproportionate dwarfism, and may result in the following:

• A height of approximately 4 feet or 122 cm in adults
• Short upper arms and upper legs
• Short fingers
• Limited elbow mobility
• A trunk with an average size
• A large or prominent forehead and a flattened nasal bridge
• Progressive swaying of the lower back
• Progressive bowing of legs

Spondyloepiphyseal dysplasia congenita (SEDC) is a rare genetic bone growth disorder and another cause of disproportionate dwarfism. The signs of SEDC may include:

• A height of 3 feet to just over 4 feet or 91-122 cm in adults
• Average size of hands and feet
• Short arms and legs
• Short neck
• A very short trunk
• Cervical instability
• A twisted or out of shape foot
• Rounded or broad chest
• Joint problems
• Cheekbones that are slightly flattened
• Cleft palate
• Hearing and vision problems
• Progressive swaying of the lower back
• Hip deformities
• Excessive curvature of the upper spine

Proportionate Dwarfism

A relatively common cause of proportionate dwarfism is growth hormone deficiency. The condition usually occurs when there is not enough growth hormone produced, which is required for the normal growth of children.

Proportionate dwarfism usually limits children’s overall growth and development, so their head, limbs, and trunk are small but proportionate to each other. Its signs are:

• A growth rate slower than expected
• Height below the growth standard
• Delayed puberty or no sexual maturity in adolescents

Causes

Most conditions that are related to dwarfism are linked to genetic disorders. However, there are also some disorders that have unknown causes. Dwarfism is often a result of random genetic mutations in the mother’s egg or father’s sperm. Genetic disorders related to dwarfism include:

• Achondroplasia
• Turner syndrome (not inherited, but rather a random error when the eggs or sperm are formed)
• Growth hormone deficiency
• Other causes (other genetic disorders, other hormone deficiencies, and poor nutrition)

Diagnosis

Diagnostic tests for pituitary dwarfism may include:

• Appearance: Certain skeletal and facial features are associated with specific dwarfism disorders. Children's appearance may help doctors in making a correct diagnosis. 

• Measurements: A well-child exam usually includes measuring children's weight, height, and head circumference. These measurements are very important when it comes to identifying abnormal growth in children. 

• Family History: Your child's pediatrician may take a history regarding short stature in your family to help identify the average range of your family's height. 

• Hormone Tests: These tests may be ordered by the doctor to assess growth hormone levels and other hormones that are essential for your child's growth and development. 

• Genetic Tests: These tests are not usually required when diagnosing disorders related to dwarfism. However, when the doctor suspects that your child may have Turner syndrome, a special blood test may be performed to assess the X chromosomes from blood cells.

• Imaging Tests: An X-ray may be ordered by the doctor to check for any skull or skeletal abnormalities in your child. Other imaging tests can also help identify delayed bone maturation. An MRI or magnetic resonance imaging scan may help reveal any abnormalities in the hypothalamus or pituitary gland, which play major roles in the functioning of hormones. 

Treatment

Treatments for dwarfism are often used to correct and relieve problems caused by certain complications and not mainly to increase stature. Some of the treatments include:

Surgery

Surgery may be performed to help correct problems in people who have disproportionate dwarfism. Surgical procedures may involve:

• Correction of spinal deformities
• Correcting bone growth direction
• Spinal decompression
• A ventriculoperitoneal (VP) shunt - a device that helps relieve pressure on the brain due to excessive accumulation of fluid (hydrocephalus)

Limb Lengthening

There are people with dwarfism who choose to have a surgery called limb lengthening. However, this type of surgery may involve multiple procedures with accompanying risks. Due to the risks involved and the physical and emotional stress it may cause, surgery is often recommended to people who are old enough to understand and participate in the decision making process.

Hormone Therapy

Treatment using synthetic growth hormone injections may help people with growth hormone deficiency increase their final height. In hormone therapy, children regularly receive a daily dose of injection for some years until they reach their adult height, which is usually the average height of their family.

Hormone therapy may continue throughout adolescence and early adulthood to ensure proper gaining of muscle and fat. Girls with Turner syndrome need estrogen and other related hormones to begin puberty and develop sexual maturity. Hormone replacement therapy tends to continue until women reach their menopausal stage.  

Outlook

Pituitary dwarfism does not affect a person’s ability to enjoy the things that life can offer. People with dwarfism can have a family, a career, and a long and fulfilling life.

However, the condition can also lead to certain complications, which is why it is quite important to undergo annual physical examinations and seeing a specialist when needed.