Question

A 41-year-old woman complained of increased sweating over the previous 3 months. She also stated that she always seemed nervous and had heart palpitations and heat intolerance. She lost 12 pounds over the past 3 weeks and had noncramping diarrhea. On examination, her skin was warm and moist, she had a prominent stare, and she had tachycardia at 140 beats per minute. Her thyroid gland was diffusely enlarged.

Laboratory Results Total T4 = 21.2 μg/dL (4-13 μg/dL) s-TSH = 0.02 mU/L (0.3-5.0 mU/L)

1. What is the most probable diagnosis (Be specific)?

2. What is the cause this disorder?

3. What does the “s” in front of the TSH test (s-TSH) indicate and what advantages does this have in the evaluation of the disease in this case?

4. Describe the synthesis of thyroid hormones? (2)

5. Why was the TSH value decreased in this case? Describe the mechanism.

6. If both the fT4 and the TSH levels were increased would the diagnosis have been the same? IF not where is the site of the abnormality if both are increased?

Answer 1

1.probable diagnosis will be Hyperthyroidism.

2. The causes of hypothyroidism are -medication, thyroid nodules, thyroiditis, excessive iodine intake ,smoking, trauma of thyroid gland, stress ,Graves disease, toxic adenoma etc

3. In s-TSH test means sensitive thyroid stimulating hormone. so 's' indicates sensitive .the advantages of testing s-TSH are-

a.for the prediction of thyrotropin releasing hormone which stimulate TSH response.

b.for the screening for thyroid dysfunction and detecting mild subclinical features of thyroid abnormalities

c.for evaluation of those patients who are on thyroid replacement therapy

4. Mechanism of synthesis of thyroid hormone - pituitary glands are having two types of cell. intracellular cells are called as colloid .extracellular cells contain thyroid follicles . thyroid follicles cells helps for the production of T4 and T4 hormones.Steps of thyroid hormone synthesis are-

Inside follicular cell--iodine trapping occur --which oxidised iodine in follicular cell -- which synthesize thyroglobulin --iodination of thyrosine -- endocytosis and digestion of colloid --synthesis of thyroid hormone.

5.if the thyroid gland is secreting high level of T3/T4 into the colloid.this give negative feedback on anterior pituitary and thus pituitary gland decrease the secretion of TSH.

6.if fT4 and TSH both are increased then it shows the abnormality of pituitary gland.in pituitary adenoma both the value fT4 and TSH increase.