Question

a) Considering the Case Study, what are T₄ and T₃?

An 11-yo female with no significant past medical history presented with symptoms of weight loss and heat intolerance. She has also experienced a decline in grades at school. The physician ordered thyroid function tests including Free T, T3, TSH, anti-TSH receptor antibodies, anti- thyroglobulin and anti-thyroid peroxidase antibodies. The results are shown below. Test Free T4 Result 2.87 18.2 374.00 <0.018 >3000 2667 69.6 Ref Range 0.73-1.77 5.0-12.0 123-211 0.36-5.80 < 60 < 60 < 16.0 Units ng/dL ug/dL ng/dL ulU/mL TU/mL TU/mL TSH anti-thyroglobulin Ab anti-thyroid peroxidase Ab anti-TSH receptor Ab

		1. T3 is a hormone produced by the thyroid gland, and T4 is the thyroid inhibitor produced by the hypothalamus
		2. both are hormones produced by the hypothalamus that stimulate function of the thyroid gland
		3. T4 is a hormone produced by the pituitary gland that stimulates production of T3 by the thyroid gland
		4. both are hormones produced by the thyroid gland

b) why are TSH levels markedly decreased?

c) what is the diagnosis?

d) what is the specific cause of the diagnosis?

e) why would this patient exhibit the symptoms of weight loss and heat intolerance?

Answer 1

a)4- Both T3 and T4 are secreted from thyroid gland only.First the hypothalmus produces Thyrotropin releasing harmone(TRH) which triggers hypothalmus to produce Thyroid stimulating harmone(TSH),which triggers thyroid follcles to produce T3 and T4 by feed back mechanism.

b)TSH is produced by hypothalmus which triggers T3 AND T4.

When T3 AND T4 levels are less TSH levels will rise and gives pushing effect to thyroid to produce more T3 and T4.

IN this scenerio, T3 and T4 levels are more due to antibodies that acted on thyroid and stimulated T3 AND T4, TSH will reduce as a response of negative feed back mechansim.

C)As T3 AND T4 levels are more along with autoantibodies which signifies the Graves disease(auto immune hyperthyroidism)

if TSH levels are more it causes Hypothyroidism.

d)The specific cause is autoanibodies developed by our immune system which triggers thyroid to produce amore T3 AND T4 which caused the elevated levels of T3 AND T4.

e)weight loss occurs due to increased BMR (Basal metabolic rate) by T3 and T4.these harmones continuously activate body metabolism and increases consumption of more calories than normal which leads to loss of muscle mass and person appears thin.

Heat intolerance because excess thyroid harmones triggers thermogenesis.so the body heats up to maximum extent and is less tolerant to additional extra environmental heat which causes heat intolerance.