Diagnostic Tests of Thyroid Function and Disorder - Coursework Example

Introduction Thyroid is an important gland which is present on the front segment of neck. It is an endocrine gland that produces hormones called as thyroid hormone. Thyroid hormone is known to regulate body metabolism and therefore playse a crucial role in the devlopment process. Regulation of the hormone produced by this gland may result in hyperthyroidism or hypothyroidism. This regulation is organized by the hypothalamus, which is known to release TRH (Thyrotropin releasing hormone), which in turn stimulates the master gland “pituitary” to liberate TSH (Thyroid Stimulating Hormone). As all endocrine secretions, TSH is also released in the blood to reach the thyroid gland to induce the production of two thyroid hormones called as L-thyroxine (T4) and triiodothyronine (T3) since it incorporated iodine so dietary iodine is also essential for its production. There is also a feed back mechanism that works to control and check the production and release of too much or too little thyroid hormone; leading to hyperthyroidism and hypothyroidism (Davidson, 2002). Effects of Hypothyroidism (Underactivity) In pregnancy: ovulatory problems, fatigue, poor attention, weight gain, numbness, tingling of hands or feet, still birth, anemia, retarted growth, placental abruption. Medications responsible are Synthroid, Levoxyl, Levothroid, Unithroid (Arem, 1999; Ain, 2005). It occurs due to- Loss of thyroid tissues, antithyroid antibodies especially in patients with diabetes, lupus, rheumatoid arthritis, chronic hepatitis, Sjorgen syndrome, congenital (since birth). Ord’s Thyroiditis, postoperative, postpartum thyroiditis, silent thyroiditis, acute thyroiditis, iatrogenic thyroiditis, thyroid hormone resistance, euthyroid sick syndrome. Defects in the production of thyroid hormone as in the case of thyroiditis causing dimnished thyroid production and enhanced TSH level causing goiter (Arem, 1999; Ain, 2005). Certain Medicines, especially lithium based Eskalith, Lithobid results in drug induced hypothyroidism (Arem, 1999; Ain, 2005). Symptoms in different age group: a. Symtoms in infants: Constipation, poor intake of feed, retarded growth, jaundice and lethargy. b. Symptoms in children: fatigue, retarded growth and poor concentration. c. Symptoms in Adults: fatigue exhaustion, poor tolerance to cold temperatures, constipation, carpel tunnel syndrome, loss of appetite, gain in body weight, dryness of skin, diminished intellectual potentials, hoarse voice, puffed eyes, depression, unbalanced or missed menstruation (Arem, 1999; Ain, 2005). Effects of Hyperthyroidism (Overactivity) Grave’s Disease: it is ccause by excessive secretion of TSI (Thyroid Stimulating Immunoglobulin). TSI excessively excites thyroid to produce goitre, causing eye disease leading to muscular pain, double vision and weakness of eyes. Thyroiditis causing excessivie release of thyroid hormone (Arem, 1999; Ain, 2005). Pituitary adenoma Drug induced due to Amiodarone, Cordarone (Arem, 1999; Ain, 2005). Symptoms in different age group: a. Symptoms in children, behavior problems, decreseaed concentration, b. Symptoms in adults include insomnia, tremors, nervousness, feeling extreme hot even at cool areas, enhanced appetite but loss in weight augmented perspiration, no or scanty menses, pain in joints, concentration intricacies, enlarged eyes. c. Symptoms in older population encompass chest pain (heart patients), shortness of breath (patients with heart disease), muscle weakness in shoulder and thighs (Arem, 1999; Ain, 2005). Thyroid hormones bind to the carrier protein molecules in a reversible manner and only 0.3% remain unbound or free to be metabolically active. This group of carrier proteins encompass TBG (Thyroxine- binding globulin), Transthyretin (TTR), and albumin (Arem, 1999; Ain, 2005). Any kind of deficiency in TH-binding proteins may be genetic due to inheritance of defective TBG gene or acquired due to hyperthyroidism, nephrotic syndrome, chronic renal failure, or any kind of severe liver disease, HIV or AIDS, under the condition of malnutrition, some other hormonal problems leading to acromegaly or cushing syndrome, or due to intake of various drugs like androgens, glucocorticoids, L-asparginase (Arem, 1999; Ain, 2005). In some cases autoimmune thyroid diseases occur where antibodies are being generated by the body against thyroid hormone. This group of antibodies is known as thyroid antibodies, they are also known as thyroid autoantibodies; antimicrosomal antibody, thyroid microsomal antibody, thyroperoxidase antibody, thyroperoxidase antibody, TPOAb, Anti-TPO, TBII, Antithyroglobulin antibody, TgAb, TSH receptor antibody, TRAb, Thyroid stimulating immunoglobulin, TSI, Thyroid stimulating hormone receptor antibody (TRAb, in case of hyperthyroidism) (Arem, 1999; Ain, 2005). In pregnancy, mothers develop thyroid autoimmunity and form antibodies for thyroid peroxidase (TPOAb) its presence in early pregnancy is the indicator of postpartum thyroid dysfunction (PPTD). It is also observed in the studies that presence of TPOAb in pregnancy at early stages also symbolizes the signs of depression., impaired neuropsychological development of the child (Premawardhana, 2004). The tests for thyroid antibodies are ordered to know the possible reasons of goitre,, Hashimoto’s thyroiditis, Grave’s disease Thyroid cancer, or when there is reproductive failure is reported by the patient or in case of premature delivery and in-vitro fertilization failure (Premawardhana, 2004). Diagnostic Tests Blood Test for TSH Free (T4) T3/ Triiodothyronine TSH receptor Antibody (TSI) in patients suffering with Grave’s disease (Ain, 2005). Anti-Thyroid Antibody in patients suffering with Grave’s disease and also in Hashimoto disease. Thyroid Scan to study x-ray image, a small amount of radioactive iodine is injected into the blood to test its absorption by the thyroid gland if it the uptake is enhanced then it is an indication of hyperthyroidism but diminished uptake leads to hypothyroidism (Ain, 2005). Ultrasounds help to find the different types of nodules in the thyroid gland. For TBG it is recommended when TSH, free T4, free T3 are normal but total T4 and T3 are low; there is a variation in TBG level, especially in patients with slight secondary TBG deficiency and partial acquired deficiency or in cases with Turner’s syndrome (Ain, 2005). Tests for thyroid antibodies indicate that there are chances of hyperthyroidism or hypothyroidism in the developing fetus in early childhood or later. Moreover these test help the physicians to rule out the possible risk of thyroid dysfunction in the fetus or ne born as these are the molecules possessing the ability to cross the placenta (Ain, 2005). Calcitonin is another thyroid hormone that regulates calcium levels it elevates the level of calcium on the bones (Ain, 2005). Case 1: A patient who has undergone surgery of thyroid gland shows high TSH and low values or FT4 and FT3, indicating that there is insufficient T4 and therefore the master gland pituitary is sending the signal to the thyroid gland which is actually removed; to make more of T4, since the body can counterweigh T3 to T4 and this is depicted in the report showing high value of T3. Case 2: A patient was reported the symptoms of insomnia, fatigue, stress, depression, high level of anxiety and severe cold. He got the report indicating below optimal values of TSH, below optimal values for FT3 and below optimal values for FT4. This indicates that the master gland is releasing less amount of TSH and as a result there is a fall in the T4 level and T4 to T3 conversion, this is displayed as a result of stress. Interpretation: As mentioned that the free form of T3 and T4 are the active hormones. In the reports, TSH refers to the hormone present in the blood whereas total T4 refers to the T4 that is not available and also the free T4. In case if the person is possessing high levels of estrogens, the T4 is less available in free form displaying symptoms of hyperthyroidism which is actually not the case. Total T3 refers to the total T3 bound as well as free. Free T4 refers to the unbound T4, which can be converted to T3 in the body or it is converted to RT3. Free T3 refers to the functional T3 to produce energy. RT3 refers to reverse T3 (Ain, 2005). If a patient is showing high T4 and low T3 then RT3 will also be high. 1. “TSH” test/ Thyroid Stimulating Hormone/ Serum Thyrotropin Normal range: 0.3 to 3.0 < 0.4= Hyperthyroidism, >3 hyperthyroidism. 2. Total T4/ Serum thyroxin 4.5 to 12.5, < 4.5 Hypothyroidism >12.5 shows hyperthyroidism. Low T4 with low TSH= Pituitary problem 3. Free T4/ Free Thyroxine- FT4 value is 0.7 to 2.0 Read More