Symptomatology, Diagnosis & Pathology 1B
Q1) Disorders of Endocrine Control of Growth and Metabolism (10 marks)
i.When testing for hypothyroidism, why is the free T4 level an important measurement? Predict what the TSH and T4 test results would indicate in someone with primary hypothyroidism. Explain your answer. (100 – 200 words, 5 marks)
Hashimoto thyroiditis is a common disease caused by hypothyroidism. The immune system cells attack the thyroid gland, causing inflammation and eventually destruction of the gland. This reduces the thyroids ability to make hormones. These hormones are known as thyroxine (T4) and tri-iodothyronine (T3) (Better health channel 2015).
In order to evaluate thyroid function and diagnose thyroid diseases such as hyperthyroidism or hypothyroidism, the free thyroxine (free T4) lab test is performed usually after discovering that the thyroid stimulating hormone (TSH) level is abnormal (Porth C 2014 p.1288)
T4 and T3 usually circulate in the blood bound to protein and only a small percentage is free (not bound). Blood tests can measure total T4, free T4, total T3, or free T3. The total T4 can be affected by the amount of protein available to bind to the hormone. The free T4 test is thought to be a more accurate reflection of thyroid hormone function, as it is not affected by protein and is the active form of thyroxine (AACC 2015).
In general, high free T4 results may indicate an overactive thyroid gland (hyperthyroidism), and low free
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According to The National Institute of Diabetes and Digestive and Kidney Diseases, diagnosis of Hashimoto’s thyroiditis begins with a physical exam and medical history. A goiter, nodules, or growths may be found during a physical exam, and symptoms may suggest hypothyroidism. Health care providers will then perform blood tests to confirm the diagnosis. Diagnostic blood tests may include the TSH, which, if above normal lab values, means a patient has hypothyroidism. Blood tests also include T4, which is the amount of thyroid hormone in the blood. In hypothyroidism, the blood lab values are lower than normal. The anti-thyroid antibody tests look for presence of thyroid autoantibodies. Most people with Hashimoto’s disease have these antibodies; however, hypothyroidism isn’t always caused
Laboratory Report/ Miranda Tefft/ Homeostatic Imbalances of Thyroid Function/ Aline Potvin/ 11.18.2014/ Page  of 
As the most interesting patient presentation, two weeks ago there was a 50-year-old Hispanic woman who came to the clinic and complained of unintentional weight gain over 28 pounds in the last two years. The patient wanted to participate in the weight loss program. Upon the physical assessment, this patient stated that her family runs thyroid disorder issues. Prior to starting the weight loss management, my preceptor and I decided to run some lab works to assess her TSH, Free T4, T3, and some other test. The patient has a follow-up appointment in the following week for her lab result. The patient lab’s result abnormal thyroid hormones. She had hypothyroidism. She stated that she had a primary physician that she had seen over 10 years, and they never told her about this problem. The plan was to treat the thyroid problem by prescribing her Armour Thyroid starting at 30 mg. According to Woo and Wynne (2015), for patients who are clinically hypothyroid, replacement therapy with thyroid hormones is
Most T3 and T4 released into the bloodstream are bound to proteins. Only the "free" component is biologically active and it is this component which decides the manifestations of thyrotoxicosis. The hormones exert their effects mainly by binding to nuclear receptors in cells to affect expression of genes.
Incidentally, there are actually two compounds made in the thyroid that are called thyroid hormone. The most abundant is T4, also known as thyroxine, which is then converted to T3, or triiodothyronine. T3 is the active form that produces the effects on metabolism.
The patient’s diagnosis is primary overt hypothyroidism. The patient presents with certain features such as weight gain, weakness, excessively dry flaking skin, dry hair, sluggish movements, constipation, bradycardia, diminished deep tendon reflexes, and bilateral edematous hands, which is classical signs and symptoms for primary hypothyroidism. The patient laboratory test reveals she has an elevation in serum thyroid stimulating hormone level along with low serum free thyroxin and triiodthyronine levels, which indicates it is a dysfunction or abnormality in the thyroid gland as opposed to the pituitary gland or hypothalamus (Gaitonde; Lohano; Porth, 2015, p. 780; Ross, 2014).
Some of these diagnoses include a physical exam, blood sample, radioactive iodine uptake and ultrasound1. With a physical exam, the doctor will check the patient’s eyes to see if they are bulging out or the area around the eye looks enlarged. They well check to see if the thyroid gland is abnormally large and because of its association with increase metabolism, the doctor will check the pulse and blood pressure of the patient and look for signs of tremors which are involuntary quivering movements1. Only in severe cases will a blood test detect TSI in the bloodstream, if TSI does not show up in a patient’s blood, then a radioactive iodine may be conducted. This is because the thyroid intakes iodine from the bloodstream and uses that iodine in order to make thyroid hormones so the radioactive iodine is inserted in the bloodstream and is collected by the thyroid gland, is the thyroid gland collects large amounts of this radioactive iodine, then the patient may have Graves’ disease3. If the patient is pregnant, that patient cannot undergo radioactive treatment because the radioactive iodine could harm the fetus’ thyroid and can be passed from the mother to the child in breast milk if the mother is breastfeeding4. An ultrasound can use the high-frequency waves to produce images of structures inside the body and can show if the thyroid gland is enlarged or
The thyroid gland is found in the front of the neck and produces two main hormones. The hormones are called thuroxine (T4) and Triiodothyronine (T3). Together these hormones regulate the body’s metabolism by increasing energy use in cells, regulate growth and development, help to maintain body temperature and aid in oxygen consumption. These two hormones are regulated by hormones produced by the hypothalamus and pituitary gland. The hypothalamus senses changes in body’s metabolic rate and releases a hormone known as thyropin-releasing hormone (TRH). This hormone then flows through connecting vessels to the pituitary gland which signals it to release another hormone. This hormone is known as thyroid-stimulating hormone (TSH). TSH then makes
To get a diagnosis, a provider will assess a patients symptoms and if they are indicative of hypothyroidism, blood and antibody tests would be taken (Mayo Clinic Staff, 2016). These tests indicate the amount of thyroid hormone and thyroid-stimulating hormone (TSH) produced in the pituitary gland (Mayo Clinic Staff, 2016). The results will represent the fact that the immune system is producing antibodies toward proteins in the thyroid gland which is causing an inability to produce thyroid hormones (Burkhart,
The patient had a history of thyroid cancer, hyperthyroidism and abnormal TSH levels. The technologist used Iodine 123 and administered 288 uCi. The technologist used a low energy high resolution collimator and increased the zoom because the hospital does not have a pinhole collimator. The patient had a thyroidectomy done in 1985. The technologist was looking for any uptake or nodules that may be present. We didn’t expect to find much uptake because the patient had already had the thyroidectomy. What was found was surprising. The patient had their thyroid gland grow back over time especially the right lobe. According to an article in Clinical Endocrinology thyroid tissue being present after a thyroidectomy is not that uncommon. The study from Clinical Endocrinology showed thyroid tissue was present in about half the patients on SPECT/CT studies (Barber, Cherk, Toplisst, Serpell, Yap, Bailey & Klaff, 2014). There was more uptake on the right gland in this case study. Normal scans have homogeneous uptake in the entire gland and don’t have cold nodule’s present. Abnormal scans can have cold nodules and uptake that is not uniform throughout the gland. The physician noted that even though this study had more uptake in the right lobe it was due to the gland being thicker and more of the right gland had grown