What is the endocrine system?
The endocrine system is composed of various glands that release hormones and control vital processes in our body. For example, the endocrine system is important in regulating mood, growth and development, tissue function, metabolism, sexual function, and reproductive processes. Hormones released into the blood transfer information and instructions from a gland to other cells. Many different hormones move through the bloodstream, but each type of hormone is designed to affect only certain cells.
Hormones only bind to cells with receptors specifically designed to recognize them. A good analogy would be inserting a key into a lock, which when it fits, opens the door allowing a series of events to occur – in this case the activity of cells. If a cell does not have a receptor for the hormone, the key does not fit and there will be no effect. There can also be different receptors for the same hormone, like a master key that works on many doors, so the same hormone can have different effects on different cells.
What glands are involved in the endocrine system?
A gland is a group of cells that produces and releases chemicals. A gland selects and removes materials from the blood, processes them, and secretes (releases) the finished chemical product for use somewhere in the body. The hypothalamus, pituitary, thyroid, parathyroid glands, adrenal glands, reproductive (ovaries & testes) glands and pancreas are the major glands that make up the endocrine system. The endocrine system is a finely tuned, interconnected system giving it the ability to have a variety of effects throughout our bodies.
How common are endocrine abnormalities in PHACE syndrome and which glands are generally involved?
Only 15 instances of endocrine abnormalities in children with PHACE syndrome have been reported in the medical literature. Endocrine dysfunction has been a recent discovery in patients with PHACE syndrome, so it is unknown whether it is a rare finding or whether it has not been previously recognized. The most common glands that have been observed to show abnormalities include the pituitary and the thyroid.
Endocrine dysfunction associated with the pituitary gland is called hypopituitarism. Hypopituitarism is a condition in which the pituitary gland does not produce normal amounts of some or all of its hormones. Because the pituitary releases many hormones that act on other glands of the body, hypopituitarism can lead to low levels of multiple hormones. The most common hormone deficiencies in PHACE syndrome are growth hormone deficiencies, hypogonadism (low levels of sex hormones) and diabetes insipidus (a condition in which the kidneys are unable to conserve water).
Hypothyroidism is a thyroid dysfunction in which the thyroid does not make enough of its hormone. In PHACE syndrome, this condition often occurs because the thyroid gland did not move to its proper location during development. This condition is referred to as an ectopic thyroid gland.
What are the signs and symptoms of an endocrine abnormality?
Due to the wide range of hormone functions, a number of signs and symptoms can occur. In recent cases, the most noticeable observation seen among PHACE syndrome patients has been growth deficiencies including both height and weight. Signs of hypothyroidism to watch for include weakness, fatigue, cold upon touch and weight gain.
How are endocrine abnormalities diagnosed and treated?
If endocrine abnormalities are suspected, a physician can order blood work to check hormone levels. Depending on the endocrine dysfunction that is occurring, hormone replacement therapy is available. For example, in PHACE syndrome children with growth deficiencies, growth hormone may sometimes be given. Thyroid replacement therapy in hypothyroidism cases has also been successful.
If concerns arise about a child's endocrine system, they should first be discussed with the primary care physician. A referral to an endocrinologist for further evaluation may be necessary.