What if t4 is normal and tsh is high

A guideline for initiating and monitoring thyroid hormone replacement therapy is provided in Figure 1. Because thyroid hormone has a large volume of distribution and long half-life, parenteral replacement is unnecessary in patients who are unable to take medication orally for a few days to a week.

However, some patients may be unable to take oral medications for much longer periods. Intravenous administration is advised in these patients and in those who need to begin thyroid hormone replacement but cannot take oral medications.

Only about 70 to 80 percent of an oral dose of replacement medication is absorbed. Therefore, parenteral replacement should be initiated at 70 to 80 percent of the usual oral dose.

The TSH level can be mildly elevated when the free T 4 and T 3 levels are normal, a situation that occurs most often in women and becomes increasingly common with advancing age. Initiation and monitoring of treatment for hypothyroidism. Thyroid hormone replacement may have some benefits in patients with subclinical hypothyroidism, but there is also a potential for adverse effects, particularly in older patients.

Some studies have shown that supplementation of thyroid hormone accelerates bone mineral loss in older women with subclinical hypothyroidism, and that estrogen replacement therapy does not counteract this effect.

Thyroid hormone replacement has also been reported to decrease serum homocysteine levels. At this time, the approach to patients with subclinical hypothyroidism must be individualized. In patients at higher risk for osteoporosis or fractures, the deleterious effects of excessive thyroid hormone can be avoided by withholding replacement until the free T 4 and T 3 levels drop below normal.

In patients with hyperhomocysteinemia, existing cardiac disease or risk factors for heart disease, early thyroid hormone replacement may offer more advantages.

Right now, consensus is lacking on how to manage patients with subclinical hypothyroidism. More research is needed to sort out the most appropriate management. Because thyroid hormone is highly protein bound, medical conditions that alter the amount of binding hormones and drugs that compete for binding may change the amount of available free thyroid hormone.

The thyroid replacement dosage must be changed in response to alterations in binding status. With conditions that cause an increase in serum binding proteins, such as high estrogen states e. In contrast, androgens decrease levels of thyroid binding proteins, necessitating a reduction in the dosage.

Older patients also have lower serum protein levels and may require reductions in their maintenance dosage over time. Nephrosis, protein-losing enteropathies and cirrhosis are other conditions that require a reduced thyroid hormone dosage.

A number of medications reduce the absorption of thyroid hormone from the intestines, necessitating an increase in the replacement dosage Table 4. When these medications are started or adjusted, the TSH value should be monitored to determine whether additional thyroid hormone replacement is indicated.

Poor compliance is the most common reason for continued elevation of the TSH level in patients receiving presumably adequate thyroid hormone replacement. Very rarely, patients have tissue-level unresponsiveness to thyroid hormone. This condition reflects a mutation in the gene that controls a receptor for T 3 , rendering it unable to bind with the hormone. The genetic mutation has been identified in only families. Consequently, the TSH level remains elevated, and the patients continue to have symptoms of hypothyroidism.

These patients should be referred to an endocrinologist for further evaluation and management. Iodine-containing medications. Amiodarone Cordarone. Sucralfate Carafate. Ferrous sulfate Slow Fe. Cholestyramine Questran. Colestipol Colestid. Aluminum-containing antacids. Calcium products. Rifampin Rifadin. Carbamazepine Tegretol. Warfarin Coumadin. Oral hypoglycemic agents.

Furosemide Lasix. Mefenamic acid Ponstel. Drugs and thyroid function. N Engl J Med ; — The U. Preventive Services Task Force 23 does not recommend routine screening for hypothyroidism in asymptomatic persons. Recently, some expert panels 24 noted that screening may be beneficial in high-risk populations such as elderly women.

However, widespread screening is not likely to be cost-effective. Because of the nonspecific symptoms of hypothyroidism, many patients would be tested because of their symptoms. This practice should not be confused with asymptomatic screening. Already a member or subscriber?

Log in. Interested in AAFP membership? Measuring levels of thyroid antibodies may help diagnose the cause of the thyroid problem. While detecting antibodies is helpful in the initial diagnosis of hypothyroidism due to autoimmune thyroiditis, following their levels over time is not helpful in detecting the development of hypothyroidism or response to therapy.

TSH and FT4 are what tell us about the actual thyroid function or levels. A different antibody that may be positive in a patient with hyperthyroidism is the stimulatory TSH receptor antibody TSI. It is not a measure of thyroid function and it does not diagnose thyroid cancer when the thyroid gland is still present.

It is used most often in patients who have had surgery for thyroid cancer in order to monitor them after treatment. Tg is included in this brochure of thyroid function tests to communicate that, although measured frequently in certain scenarios and individuals, Tg is not a primary measure of thyroid hormone function. The thyroid has developed a very active mechanism for doing this. Therefore, this activity can be measured by having an individual swallow a small amount of iodine, which is radioactive.

The radioactivity allows the doctor to track where the iodine goes. By measuring the amount of radioactivity that is taken up by the thyroid gland radioactive iodine uptake, RAIU , doctors may determine whether the gland is functioning normally. A very high RAIU is seen in individuals whose thyroid gland is overactive hyperthyroidism , while a low RAIU is seen when the thyroid gland is underactive hypothyroidism.

In addition to the radioactive iodine uptake, a thyroid scan may be obtained, which shows a picture of the thyroid gland and reveals what parts of the thyroid have taken up the iodine see Thyroid Nodules brochure.

There are many medications that can affect thyroid function testing. Other thyroid tests may be a part of standard thyroid workup or used when needed. Some have specific aims. The others are used for screening purposes or to evaluate possible causes.

There are many thyroid function tests, and their names and lab value ranges may seem confusing. They all are important, though often for different reasons. What's more important are the results, a shared understanding of what those results mean, and how they will help to guide care for a thyroid-related disorder.

Your test results, symptoms, medical history, and current health are all factors when a healthcare provider looks at how well your thyroid is working. The test results are based on a common standard for each test, all of which look at thyroid function in different ways. It's not just the results, though. Many people find it helpful to know what the tests are, and which ones they had or will have. It's one way to ensure that both healthcare provider and patient are on the same page, and know how to talk about test results or tests they think may be needed.

Losing weight with thyroid disease can be a struggle. Our thyroid-friendly meal plan can help. Sign up and get yours free! Sheehan MT. Biochemical testing of the thyroid: TSH is the best and, oftentimes, only test needed - A review for primary care.

Clin Med Res. Indrasena BS. Use of thyroglobulin as a tumour marker. World J Biol Chem. Autoimmune thyroid disorders. ISRN Endocrinol. Euthyroid sick syndrome in acute ischemic syndromes. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Endocrine Prac. Value of repeat stimulated thyroglobulin testing in patients with differentiated thyroid carcinoma considered to be free of disease in the first year after ablation.

J Endocrinol. J Clin Endocrinol Metab. Your Privacy Rights. To change or withdraw your consent choices for VerywellHealth. Certainly, this is an important question which deserves continuing research. I do not imply that argument. What it means in regard to an indication to treat, or who to treat, is clearly something else. I hope we encourage more clinical studies in which we evaluate, in the normal double-blinded manner, fatigue levels, mortality and morbidity, behavioral and mood changes, and other QOL considerations.

T-3 is being given by many physicians now with the belief, based on their clinical experiences, that it is helpful. We need to have an open expression of views so we can have access to the data available from those treating their patients. Such situations can drive physicians who follow practices that might lie outside of, or straddle, clinical orthodoxy underground. It isolates and may be unfair to them.

It certainly impedes resolution of such issues in the normal scientific manner. I wholly disagree. My TSH was under 10 but I was very symptomatic.

My doctor was skeptical, but my numbers got worse and I was put on a thyroxine trial after months and months of suffering. I could have been spared what I went through. I have been on 75mcg for about 11 years and have never tested hyperthyroid. So no over- medication there, doc. Your arguments are totally wrong and out of the arc. They develop other conditions, requiring statins, diabetes meds, blood-pressure meds or vasodilators, water tablets, anti-inflammatories for joint and muscle pain, migraine meds, IBS meds and anti- depressants.

Regarding only testing TSH. Question: if you extrapolate how many people have thyroid disease in the world and calculate the number of people not captured by the TSH test, I wonder how many people would remain sick in your claimed. What do you do for those individuals?

That being said, there is plenty of research to demonstrate that TSH is not a perfect test as it tests a pituitary hormone, is not a direct measure and relies on the idea of a perfect HPT axis. Many people diagnosed with a thyroid condition are surprised that such a small gland can have such a profound impact on overall health and well-being.

But the thyroid gland plays an enormous role in human health. Throughout life, this busy gland is constantly producing hormones that influence metabolism. When disease causes your thyroid gland to slack off and underproduce thyroid hormone, or overwork and produce too much of it, you'll know something isn't right. Thyroid Disease: Understanding hypothyroidism and hyperthyroidism will help you recognize the symptoms and find the right treatment before you experience the long-term effects of this common condition.

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