Hypopituitarism

The pituitary gland is a small gland at the base of the brain that produces hormones that control many important functions in the body. In children, pituitary hormones are especially important for growth, metabolism, puberty, thyroid function and the body's response to stress.

Hypopituitarism occurs when the pituitary gland does not make enough of one or more of these hormones. The condition can affect children differently depending on which hormones are missing and how much hormone the body can produce.

Hypopituitarism may be present at birth or develop later in childhood. It can develop gradually or, in some cases, happen suddenly. Although there is no cure for most forms of hypopituitarism, hormone replacement treatment can replace the hormones the body is missing and help children grow and develop normally.

Types of Hypopituitarism

Hypopituitarism can affect one hormone or several hormones.

Growth hormone deficiency occurs when the pituitary does not produce enough growth hormone. It can cause children to grow more slowly than expected or remain shorter than other children their age.

Adrenocorticotropic hormone (ACTH) deficiency causes the adrenal glands to produce too little cortisol. Cortisol helps the body respond to illness, injury and physical stress. Severe cortisol deficiency can cause dangerously low blood pressure or blood sugar and requires prompt treatment.

Thyroid-stimulating hormone (TSH) deficiency can cause the thyroid gland to produce too little thyroid hormone. This can lead to slowed growth, fatigue, constipation, cold sensitivity, and other symptoms of hypothyroidism.

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) deficiency can interfere with puberty and reproductive development. Children may have delayed or absent puberty.

Prolactin deficiency can affect the body's ability to produce breast milk after pregnancy, although this is generally not a concern for children.

When multiple pituitary hormones are deficient, the condition is called multiple pituitary hormone deficiency.

What Causes Hypopituitarism?

Sometimes, the cause of hypopituitarism is unknown. In other children, it may result from a problem with the development of the pituitary gland or the part of the brain that controls it.

Possible causes include:

• A pituitary gland or brain abnormality present at birth
• Genetic conditions
• Brain injury
• A benign pituitary or brain tumor
• Cancer or treatment for cancer, including radiation
• Infection or inflammation affecting the brain or pituitary gland
• Autoimmune disease
• Surgery involving the brain or pituitary gland

Some children develop hypopituitarism after treatment for another medical condition.

Symptoms of Hypopituitarism

Symptoms depend on which pituitary hormones are affected and how severe the deficiency is. Children may have:

• Slow growth or short stature
• Delayed or absent puberty
• Weight loss or difficulty gaining weight
• Weight gain
• Low appetite
• Fatigue or low energy
• Low blood sugar
• Increased sensitivity to cold
• Constipation
• Pale or dry skin
• Headaches
• Vision changes
• Low blood pressure
• Increased thirst or urination

Babies with hypopituitarism may have low blood sugar, prolonged jaundice, poor feeding or poor weight gain. In boys, a small penis or undescended testicles can sometimes be a sign of certain hormone deficiencies present at birth.

Diagnosing Hypopituitarism

Diagnosing hypopituitarism can require several tests because the pituitary gland controls multiple hormones. Your child's endocrinologist will consider their growth pattern, symptoms, medical history and physical development when determining which tests are needed.

Blood Tests

Blood tests measure hormone levels and can help determine which pituitary hormones are deficient. Depending on your child's symptoms, testing may include:

• Growth hormone-related markers, such as insulin-like growth factor 1 (IGF-1)
• Thyroid-stimulating hormone (TSH) and free thyroxine (T4)
• Cortisol and other tests of adrenal function
• LH and FSH
• Sex hormones, such as testosterone or estrogen
• Blood glucose and electrolytes
• Other tests based on your child's symptoms

A single blood test cannot always diagnose a hormone deficiency. Some hormones are released in pulses or vary throughout the day, so your child's doctor may recommend additional testing.

Hormone Stimulation Tests

Some pituitary hormones require stimulation tests to determine whether the body can produce enough of a hormone when prompted.

For example, a growth hormone stimulation test may involve giving medications that stimulate growth hormone release and measuring hormone levels over several hours.

An ACTH stimulation test can evaluate whether the adrenal glands are able to produce enough cortisol.

These tests are performed under medical supervision because your child's heart rate, blood pressure, blood sugar and other vital signs may need to be monitored.

Imaging Tests

An MRI of the brain and pituitary gland can provide detailed images of the pituitary and surrounding structures. It can help doctors identify tumors, structural differences or other abnormalities that may be contributing to hypopituitarism.

A CT scan may sometimes be used when additional imaging is needed, although MRI generally provides more detailed images of the pituitary.

Other Tests

Your child's doctor may recommend additional testing depending on their symptoms. This may include:

• Monitoring your child's height and weight over time
• Tracking growth rate using a pediatric growth chart
• Bone-age X-ray to assess how mature the bones are
• Vision testing if a tumor or other brain abnormality could affect the optic nerves
• Genetic testing when a genetic cause is suspected

Treating Hypopituitarism

Treatment replaces the hormones your child's body does not produce adequately. The specific treatment depends on which hormones are deficient and what caused the condition.

Growth Hormone Replacement

Children with confirmed growth hormone deficiency may receive growth hormone injections. Treatment can help children grow at a more typical rate and reach a greater adult height.

Your child's endocrinologist will monitor growth, hormone levels and treatment response and adjust the dose as your child grows.

Thyroid Hormone Replacement

Children with thyroid hormone deficiency receive thyroid hormone replacement, usually in the form of levothyroxine. Regular blood tests help doctors make sure your child is receiving the appropriate dose.

Cortisol Replacement

Children with ACTH deficiency need cortisol replacement to provide the hormone their body cannot make adequately.

Because the body normally produces more cortisol during illness, injury or other physical stress, children with adrenal insufficiency may need higher doses during these situations. Families receive instructions about stress dosing and what to do if their child cannot take medication by mouth.

Severe cortisol deficiency can become an emergency, so it is important for families to understand how to recognize and respond to adrenal crisis.

Puberty & Sex Hormone Treatment

Children with LH and FSH deficiencies may need hormone treatment to initiate or support puberty. Treatment may include testosterone for boys or estrogen followed by additional hormone therapy for girls, depending on the underlying condition and the child's individual needs.

Treating the Underlying Cause

When hypopituitarism is caused by a tumor or another structural problem, treatment may also address the underlying condition. Depending on the cause, this could include:

• Surgery
• Radiation therapy
• Treatment for infection or inflammation
• Treatment for an underlying genetic or autoimmune condition

Long-Term Care for Children With Hypopituitarism

Hypopituitarism often requires long-term follow-up with a pediatric endocrinologist. Your child's hormone needs can change as they grow, particularly during puberty and periods of illness.

Regular appointments may include monitoring:

• Growth and weight
• Puberty and development
• Hormone levels
• Medication doses
• Bone health
• Symptoms of hormone deficiency or excess

With appropriate hormone replacement and ongoing care, many children with hypopituitarism can grow, develop and participate in everyday activities.