Hypothyroidism - One of the Most Frequently Missed Diagnoses
One of the most common conversations I have with new patients goes something like this: "Mrs. Jones, based on your symptoms and your health history we just discussed, I think it is likely that you have underactive thyroid function." The patient replies to me, "Oh, no, doctor. That's not it. I had my thyroid tested and it's fine."
There are quite a few reasons that hypothyroidism is missed. First of all, doctors over-rely on blood tests. There are certain aspects of thyroid hormone function that cannot be assessed by blood tests. For example, if thyroid hormone is not transported into the cells properly, energy production and metabolism will slow. This will not be seen on laboratory testing.
Another reason for a missed diagnosis is not doing a thorough work-up. I routinely test TSH, total T4, total T3, free T3, reverse T3, and anti-thyroid antibodies. Most doctors don't order all of these tests and, accordingly, cases of hypothyroidism are missed.
One more lab-related reason for missing the diagnosis of hypothyroidism is the way in which the results are interpreted. For example, most labs have an upper-limit of normal for TSH set somewhere about 5 to 5.5. The higher the TSH, the lower the thyroid function. TSH (Thyroid Stimulating Hormone) tells the thyroid to take up iodine from the blood, make thyroid hormone (primarily T4) and secrete it into the blood. If the thyroid is sluggish, TSH output increases in an attempt to get the thyroid to work harder. So, if your TSH is 6.0, your doctor will conclude your thyroid is underactive. However, the conventional reference range is simply not correct. TSH values should not generally be above 2.5. If yours is and you have signs and symptoms of hypothyroidism, you are hypothyroid!
Some of the main signs and symptoms of hypothyroidism include irritability, fatigue, weight gain, depression, PMS, hair loss, cold intolerance, low sex drive, water retention, and high cholesterol.
For more on hypothyroidism: Do You Need a Thyroid Tune-Up?