The hypothalamus and the pituitary gland are at the center of thyroid hormone control. The hypothalamus releasesthyrotropin– releasing hormone (TRH), which activates the pituitary gland to release thyroid-stimulating hormone (TSH). TSH then stimulates the thyroid to make and release two main hormones: thyroxine (T4) and triiodothyronine (T3) in the bloodstream.
Thyroid hormones they play an important role in virtually every aspect of your health, including metabolism, heart rate, energy expenditure, body temperature, skin, hair, and nail growth.
The three endocrine glands, known as the hypothalamus-pituitary-thyroid axis, work together in a feedback loop to keep thyroid hormone production within a normal range. If the hypothalamus and/or pituitary gland are dysfunctional or damaged, a healthy thyroid will produce insufficient levels of thyroid hormone.
This article explores the symptoms, causes, diagnosis, and treatments of central hypothyroidism.
Symptoms of central hypothyroidism
Central symptoms of hypothyroidism They vary from person to person, depending on the severity of the thyroid hormone deficiency. Common symptoms of central hypothyroidism include:
- cold intolerance
- Cognitive impairment/memory problems
- Decreased libido (sexual desire)
- Hair loss
- menstrual problems
- pale and dry skin
- recurring headaches
- Visual field changes (eg, blind spots, difficulty seeing out of the corner of the eye)
- Weight gain
Central hypothyroidism can be congenital (present at birth) or acquired in childhood or adulthood due to hypothalamic or pituitary disease or injury.
Causes of central hypothyroidism include:
How common is central hypothyroidism?
It is estimated that 1 in 13,000 people has central hypothyroidism. About 60% are part of combined pituitary hormone deficiencies.
A diagnose central hypothyroidism, your health care provider will ask about your medical history and perform a physical exam to check your vital signs, including body temperature, heart rate, and reflexes. They may palpate (feel) your neck to check your thyroid glands size, location and texture.
Important information to tell your health care provider includes:
- Symptoms you are experiencing that may be related to hypothyroidism
- Your personal history of thyroid surgery and/or radiation to the neck
- Past and current medications you are taking, as some medications can cause hypothyroidism
- Your family history of thyroid disease
Blood tests are the best way to accurately diagnose central hypothyroidism. Thyroid blood tests include:
- free T4: Measures thyroxine (T4) levels
- Total T3 levels: Measures triiodothyronine (T3) levels
- serum TSH: Measures levels of thyroid stimulating hormone
- Thyroid antibody tests—Measure the level of thyroid antibodies to help identify the cause of hypothyroidism (eg, autoimmune disorders)
- Alpha subunit (proteins) and/or prolactin (a hormone from the pituitary gland) level tests
Low TSH levels are often associated with primary hyperthyroidismwhile low T4 with low to normal TSH levels are hallmark indicators of central hypothyroidism.
Your health care provider may order imaging tests, such as an MRI magnetic resonance of the hypothalamus and/or pituitary, to check for tumors or defects that may be the cause of CeH. Genetic testing may be done if the cause is unknown or if you have a family history of the disease.
The standard treatment for central hypothyroidism is an oral medication called Synthroid, Levoxyl, Unithroid, or Levothroid (levothyroxine). This synthetic version of the thyroid hormone, thyroxine (T4), is taken daily to restore normal T4 levels. Your healthcare provider will choose your starting dose based on your body weight and the severity of your symptoms.
Routine blood tests are required frequently (every four to eight weeks) at the start of medication to check thyroid hormone levels. Dose adjustments will be made as needed based on test results and symptoms. Once your thyroid hormone levels stabilize within normal ranges, monitoring will be required once or twice a year.
If a pituitary and/or hypothalamic disorder is the cause of central hypothyroidism, treatment of the underlying cause may begin before starting thyroid hormone replacement therapy. There is no cure for central hypothyroidism, so lifelong treatment may be required.
Central hypothyroidism (Ceh) is a rare form of hypothyroidism caused by abnormal function of the pituitary gland, hypothalamus, or both, causing the thyroid to produce insufficient hormone levels.
People with CeH may experience mild symptoms of hypothyroidism (eg, fatigue) along with other symptoms such as recurrent headaches and vision disturbances (eg, double vision). Symptoms of pituitary dysfunction may also occur.
A complete physical exam and thyroid blood tests are required to accurately diagnose central hypothyroidism. Low T4 levels, with inappropriately low and inappropriately normal TSH levels, are hallmark indicators of the condition. Thyroid hormone replacement therapy is the most common treatment for CeH. Levothyroxine, a synthetic version of the thyroid hormone T4, is taken daily to restore and balance thyroid hormone levels and reduce symptoms.
A word from Verywell
The symptoms of central hypothyroidism can interfere with your quality of life, but getting treatment can help manage the condition and improve your overall well-being. Talk to your health care provider if you have symptoms of hypothyroidism. They can refer you to a endocrinologist—a medical care specializing in the diagnosis and treatment of thyroid diseases— to provide an accurate diagnosis and recommend the best course of treatment.
What is the difference between primary and central hypothyroidism?
Primary hypothyroidism is caused by a diseased or dysfunctional thyroid associated with high levels of thyroid-stimulating hormone (TSH). Central hypothyroidism is caused by hypothalamic and/or pituitary dysfunction or disease that affects the function of a normal thyroid.
How common is central hypothyroidism?
Central hypothyroidism is rare. It is estimated that 1 in 13,000 people (including infants, children, and adults) are diagnosed with this condition.
How is central hypothyroidism tested?
Thyroid blood tests that measure the levels of thyroid hormone in the bloodstream are used to diagnose central hypothyroidism. The condition is associated with low thyroxine (T4) levels and low to normal thyroid-stimulating hormone (TSH) levels.