What is Subclinical Hypothyroidism?

What is Subclinical Hypothyroidism?

Subclinical Hypothyroidism and Chronic Fatigue Syndrome


Subclinical hypothyroidism is basically a low-level or mild form of thyroid failure, one which many doctors will not treat.  When I was first diagnosed with hypothyroidism, I was told by my primary care physician that he would not treat it.  In his opinion, the blood test results did not a high enough degree of hypothyroidism to warrant treatment.  This, despite the fact that I was extremely tired and exhibited many of the signs and symptoms of hypothyroidism!  I visited my holistic doctor, who decided to take a different approach and treat the condition.  I am so happy that he did, because within just a couple of weeks I had a noticeable uptick in the amount of energy that I had.

So, how is subclinical hypothyroidism defined?

Subclinical hypothyroidism is defined as an elevated serum Thyroid Stimulating Hormone (TSH) level associated with normal total or free T4 and T3. Overall, the prevalence of subclinical hypothyroidism is estimated to be in the range of 4-10% of the general population, so it is not exactly a rare condition. And because the difference in how you feel if you are treated can be dramatic, it is important to find a doctor who will be aware of the need to treat subclinical hypothyroidism.  Those of us with chronic fatigue syndrome who are also suffering from hypothyroidism or subclinical hypothyroidism can often benefit greatly from treatment.

Some doctors feel that because the free T4 and T3 levels are normal, the patient is not hypothyroid, even when they have an elevated serum (blood) TSH level.  However, as long as the TSH level is elevated, the individual’s thyroid hormone levels are not normal.  Elevated TSH levels how that circulating levels of T3 an T4 are insufficient, and so TSH hormone is increased to direct the thyroid to create more thyroid hormone. With subclinical hypothyroidism,the pituitary gland, which is in charge of regulating the thyroid gland, produces extra amounts of TSH to instruct the thyroid increase its output of of thyroid hormones in order to maintain normal serum levels of thyroid hormones. While technically, the individual is not hypothyroid, since the circulating levels of T3 and T$ are normal their pituitary is working overtime to maintain thyroid hormone levels within the normal range. For a significant number of patients, TSH levels must continue to climb in order to stimulate the thyroid gland to produce hormones. Eventually, over a course that can range from months to years, the thyroid gland can no longer respond adequately.  Once this happens, sub-clinical hypothyroidism becomes overt hypothyroidism.

Does Sublinical Hypothyroidism Progress to Overt Hypothyroidism?

Mild thyroid failure, or subclinical hypothyroidism, usually represents an early stage of thyroid disease that can progress to full-blown hypothyroidism.  One study showed that over a 10-year period of time, 34% of patients progressed to overt hypothyroidism.  Approximately 30% of patients with subclinical hypothyroidism have symptoms that suggest thyroid hormone deficiency.  These symptoms can be alleviated with proper treatment consisting of thyroid hormone replacement medication.

Should You Seek Treatment?

If you are diagnosed with “sub-clinical hypothyroidism,” you should discuss the pros and cons of thyroid treatment with your doctor. Regardless of the decision that you make, it is important to have continued follow-up visits with your doctor. Once you have started treatment, you should have your thyroid levels checked periodically while on replacement therapy. I have my levels checked every six months, and more often if I notice a marked and unexplainable change in my energy levels. If you have decided to put off treatment, you should also have periodic blood tests to see if you have progressed to overt hypothyroidism.

Since the health effects of hypothyroidism can be serious, you should maintain a close relationship with your doctor to ensure that you are following a proper treatment protocol. I can say that in my case, the benefits of early treatment were enormous, and have me the energy that I needed to continue my research into finding a cure to my chronic fatigue syndrome.