History: 72-year-old female complaints with a history of gaining weight, increased fatigue, dry skin and hair loss over the past 6 months. Her medical record shows a history of type 2 diabetes, hypertension, and hyperlipidemia. Thyroid function test was ordered, and results shows TSH 18.3, while the normal range is 0.4-4.0 and T4 is 2.3 whereas normal range is 4.6 to 12.0.
Laboratory studies: Patient ordered with TFT’s and result shows:
• TSH- 18.3 (Normal 0.4-4.0)
• Free T4- 2.3 (Normal 4.6-12)
Interpretation and results:
Elevated TSH and Low free T4 indicates primary hypothyroidism due to abnormal or disease in thyroid gland.
High TS usually indicates thyroid gland failed because of this problem, the patient will be affected by primary hypothyroidism. In contrast, If TSH is low, because of the overactive thyroid which produces more thyroid hormone, leads to hyperthyroidism. In similar condition, low TSH results of some abnormality in pituitary gland is termed as secondary hyperthyroidism. (Anon., n.d.)
T4 bound to protein in the bloodstream, which prevents the T4 to enter various tissues, needed the thyroid hormone. Free T4 will enter various target tissue and exert its effect. So, Free T4 fraction or FT4 or Free T4 index(FTI) are important to determine thyroid function test. Therefore, Combination of TSH test with FTI determines how thyroid gland functioning in our body.
In TFT, T3 is rarely helpful because its last test to show abnormal results. Usually, patients suffering from hypothyroid with high TSH and low FT4 will have normal levels of T3.
Patients have history of type 2 diabetes, have increased cases of hypothyroidism. This is more common incidence among older adults. It possesses a major association with weight because hypothyroidism can cause weight gain, which is in turn associated with type 2 diabetes. (Erika Gebel, 2011)
Overt hypothyroidism is a secondary cause of hyperlipidemia and associated coronary heart disease. (Razvi S, 2008). Regulation of lipid metabolism is mostly based on thyroid levels, since its mostly act on nuclear receptors such as thyroid hormone receptor ? and ?) which helthe ps in regulation of gene expression linked to lipid metabolism. (Teng, 2014)
Next step in evaluation:
• Detection of Antibodies against thyroid that may either damage or stimulates the thyroid gland. Thyroid peroxidase and Thyroglobulin are common antibiotics that cause thyroid problems. These antibodies are called as Thyroid stimulating immunoglobulins (TSIs). Positive results for anti-thyroid peroxidase and/or anti-thyroglobulin are major suspect for Hashimoto thyroiditis. In case, these antibiotics are positive in a patient with hyperthyroidism, most likely diagnosis is autoimmune disorder such as grave’s disease. Grave disease is a kind of autoimmune disorder caused by immune system creates auto bodies which make your thyroid to enlarge, which leads to increased production of thyroid gland. It most likely affects women than men. (Daniel J. Toft MD, n.d.)
• Other tests, such as Imaging test or Radioactive Iodine uptake test, a using small dose of radioactive iodine. Thyroid hormone collects iodine from the bloodstream and uses it. Likewise, radioactive iodine is collected by thyroid which is analyzed by imaging the distribution.
• Thyroid scan will tshow the distribution of thyroid hormones or lumps in the gland or iodine will show in different types of pattern.
• Treatment for hypothyroidism involves daily use of the synthetic thyroid hormone levothyroxine (Levothroid, Synthroid, others). This oral medication restores adequate hormone levels, reversing the signs and symptoms of hypothyroidism.
Treatment commonly suggested for hypothyroidism will be daily use of synthetic thyroid hormone levothyroxine such as Levothroid, Synthroid etc. These oral medications will restore most signs and symptoms. May reverse weight gain, hair loss, elevated lipid levels. (Mercuro G, 2006)
Follow up, will be the bi-annual and annual screening of thyroid level, and medication will be taken lifelong. Alternation in dosage level will be consulted by the doctor upon variation in TSH levels and T4 levels.
After 2 years of normal TFT’s and treatment, patient’s complaints with atrial fibrillation, tremor and hypertension and TSH level below 0.1
• Usually, Atrial fibrillation occurs in the most patient with hyperthyroidism because, low serum thyrotropin concentration is a risk factor for the occurrence of atrial fibrillation. Thyroid hormones lead to arrhythmogenic activity by changing the characteristics of atrial myocytes and altered pulmonary vein cardio myocytes. These thyroid hormones will extend its adverse effect on cardiovascular effects either through nuclear thyroid receptors or by sympathoadrenergic systems influence, which bring alteration in peripheral vascular resistance. These binding of thyroid hormones with nuclear receptors will result in gene transcription of cardiac myocyte protein. (Jayaprasad M.D et, 2006)
• Thyroid hormones will regulate activities such as sarcoplasmic Calcium ATPase, myosin heavy chain alfa, voltage gated K+ channels, Na+ channels and beta1 adrenergic receptors. These effect results in dramatic rise in heart rate, hypertension, cardiac hypertrophy, and elevated ventricular contractility, which leads to dysrhythmias, particularly atrial fibrillation. Increased oxygen demand of tissue and reduce peripheral vascular resistance leads to increase cardiac action.
• Low TSH will indicates secondary hypothyroidism with low fT4 or else, extremely level TSH with High fT4 will leads to hyperthyroidism. So FT4 will be measured to come up with final suspension of abnormality.
• Main stream treatment for patients with atrial fibrillation with thyroid abnormalities will be restoration of euthyroid status, using drugs such as carbimazole, propyl thiouracil or radio-iodine. Surgery of thyroid gland will be done if needed, by achieving necessary euthyroid status by drugs. Betablockers such as propranolol or atenolol, useful to reduce heart rate and cardiac failure. (Dr. Jack Merendino, 2018)
• Treatment with anti-thyroid medication such as methimazole or propylthiouracil, radioactive iodine or surgery will hethe lp in management of both thyroid disease associated with atrial fibrillation. (Biondi B, 1994)
Biondi B, F. S. C. C. e. a., 1994. Control of adrenergic overactivity by beta blockade improves quality of life in patients on long-term suppressive therapy with levothyroxine. Journal of Clinical Endocrinology and Metabolism, 78(PubMed), p. 1028–1033.
Daniel J. Toft MD, P. R. M. S. M. P., n.d. endocrineweb-Vertical Health LLC. Online
Available at: https://www.endocrineweb.com/conditions/graves-disease/graves-disease-overview
Accessed 07 (06) 2018.
Dr. Jack Merendino, M., 2018. Endocrinology Diabetes & Metabolism-How is hyperthyroidism with atrial fibrillation treated?. Online
Available at: https://www.sharecare.com/health/hyperthyroidism/how-hyperthyroidism-atrial-fibrillation-treated
Erika Gebel, P., 2011. www.diabetesforecast.org:Detecting Thyroid Disease:People with diabetes are prone to disorders of this gland. Online
Available at: http://www.diabetesforecast.org/2011/mar/detecting-thyroid-disease.html
Jayaprasad M.D et, a., 2006. Atrial Fibrillation and Hyperthyroidism.. Indian Pacing Electrophysiol Journal, 5(4), pp. 305-311.
Mercuro G, P. M. B. A. e. a., 2006. Cardiac function, physical exercise capacity, and quality of life during long-term thyrotropin-suppressive therapy with levothyroxine: effect of individual dose tailoring. Journal of Clinical Endocrinology and Metabolism., 85(7), p. 159–164.
Razvi S, S. A. V. M. W. J. P. S., 2008. The influence of age on the relationship between subclinical hypothyroidism and ischemic heart disease: a meta-analysis. J Clin Endocrinol MetabPubMed, 93(8), pp. 2998-3007.
Teng, T. J. a. X., 2014. Update on Lipid Metabolism and Thyroid Disorders. Journal of Endocrinology, Diabetes & Obesity-SciMed Central, 2(3), p. 1043.