Week 5—Endocrine Cases for Discussion
Case 5.A—Graves’ Disease solved
Week 5—Endocrine Cases for Discussion
Case 5.A—Graves’ Disease
An otherwise healthy 38-year-old woman presents with 8 months of feeling anxious
and tremulous. She reports having experienced intolerance to heat, weight loss,
weakness, and palpitations. On exam her pulse is 118 and blood pressure is 160/88
mmHg. She had
a mild lid lag; a moderately enlarged, nontender thyroid; and hyperreflexia.
Laboratory tests were remarkable for elevated titers of thyroid-stimulating
immunoglobulins (TSI) and depressed TSH levels (<0.1 mU/ml). She is treated with
propranolol and thionamides (propylthiouracil (PTU) and considered for radioactive
iodine (RAI 131I) therapy.
1. Draw a feedback loop to illustrate how thyroid hormone (TH)
release is regulated in the normal patient. Explain what is different
in our patient.
Increase in thyroid hormone is detected by sensors in hypothalamus or anterior
pituitary gland→ reduction of secretion of TSH → subsequent decrease in the output
of thyroid hormone. Our patient is different because the sensors are not working
and therefore continuing to excrete TSH despite already high levels.
2. What are the general functions of TH in the body? Briefly explain
our patient’s symptoms based upon your prediction about her TH
levels.
Thyroid hormone is a major metabolic hormone. TH refers to two iodine-containing
hormones, T4 (thyroxine) and T3 (triiodothyronine). TH regulates metabolism and is
important for growth and development and regulation of metabolism throughout
life. The patient’s symptoms are caused by the autoimmune disease Graves’
disease, which leads to overstimulation of the thyroid gland and the release of
excess TH. This is why the TSH is so low. There is no need for TSH to be released
when the TH levels are so high. The elevated TH leads to an enlarged thyroid, as
well as the weight loss, weakness, palpitations, elevated HR, and heat intolerance
she is experiencing.
3. Given the decreased levels of TSH and increased TSI, what would you
predict our patient’s level of TH would be and why?
TH would be elevated because the thyroid is being stimulated to produce TH’s due
to the autoimmune antibody response to the disease.
4. What kind (steroid, peptide, etc.) of hormone is TH? How is it
transported in the blood? Where does it bind its receptor? What is the
target cell response (second messenger activation or transcriptional
activation)?
Thyroid hormone is considered the amino acid hormone, which is derived from two
iodinated tyrosine amino acid residues. TH are bound to thyroxine-binding globulin
(TBG) and other plasma proteins, mainly transthyretin and albumin, to be
https://www.coursehero.com/file/39310168/Week-5-Case-Studiesdocx/
, Week 5—Endocrine Cases for Discussion
Case 5.A—Graves’ Disease solved
transported in the blood. In the cell, T3 diffuse across the cell membrane into the
cytoplasm of the target cell. Once inside T3 binds to and activate an intracellular
receptor. The hormone- receptor complex then moves to the nucleus, where
hormone binds to a hormone
This s rtuedysspouorcenwsaes doewlnelomadeed bny t10(0H000R82E99)074i9n8 ftrohmeCopurrseoHmero.ocotmeorn s08 o-05n-
20a21 t0a7:1r5g:0e7 Gt MgTe-0n5:e00 or to another transcription
https://www.coursehero.com/file/39310168/Week-5-Case-Studiesdocx/
Case 5.A—Graves’ Disease solved
Week 5—Endocrine Cases for Discussion
Case 5.A—Graves’ Disease
An otherwise healthy 38-year-old woman presents with 8 months of feeling anxious
and tremulous. She reports having experienced intolerance to heat, weight loss,
weakness, and palpitations. On exam her pulse is 118 and blood pressure is 160/88
mmHg. She had
a mild lid lag; a moderately enlarged, nontender thyroid; and hyperreflexia.
Laboratory tests were remarkable for elevated titers of thyroid-stimulating
immunoglobulins (TSI) and depressed TSH levels (<0.1 mU/ml). She is treated with
propranolol and thionamides (propylthiouracil (PTU) and considered for radioactive
iodine (RAI 131I) therapy.
1. Draw a feedback loop to illustrate how thyroid hormone (TH)
release is regulated in the normal patient. Explain what is different
in our patient.
Increase in thyroid hormone is detected by sensors in hypothalamus or anterior
pituitary gland→ reduction of secretion of TSH → subsequent decrease in the output
of thyroid hormone. Our patient is different because the sensors are not working
and therefore continuing to excrete TSH despite already high levels.
2. What are the general functions of TH in the body? Briefly explain
our patient’s symptoms based upon your prediction about her TH
levels.
Thyroid hormone is a major metabolic hormone. TH refers to two iodine-containing
hormones, T4 (thyroxine) and T3 (triiodothyronine). TH regulates metabolism and is
important for growth and development and regulation of metabolism throughout
life. The patient’s symptoms are caused by the autoimmune disease Graves’
disease, which leads to overstimulation of the thyroid gland and the release of
excess TH. This is why the TSH is so low. There is no need for TSH to be released
when the TH levels are so high. The elevated TH leads to an enlarged thyroid, as
well as the weight loss, weakness, palpitations, elevated HR, and heat intolerance
she is experiencing.
3. Given the decreased levels of TSH and increased TSI, what would you
predict our patient’s level of TH would be and why?
TH would be elevated because the thyroid is being stimulated to produce TH’s due
to the autoimmune antibody response to the disease.
4. What kind (steroid, peptide, etc.) of hormone is TH? How is it
transported in the blood? Where does it bind its receptor? What is the
target cell response (second messenger activation or transcriptional
activation)?
Thyroid hormone is considered the amino acid hormone, which is derived from two
iodinated tyrosine amino acid residues. TH are bound to thyroxine-binding globulin
(TBG) and other plasma proteins, mainly transthyretin and albumin, to be
https://www.coursehero.com/file/39310168/Week-5-Case-Studiesdocx/
, Week 5—Endocrine Cases for Discussion
Case 5.A—Graves’ Disease solved
transported in the blood. In the cell, T3 diffuse across the cell membrane into the
cytoplasm of the target cell. Once inside T3 binds to and activate an intracellular
receptor. The hormone- receptor complex then moves to the nucleus, where
hormone binds to a hormone
This s rtuedysspouorcenwsaes doewlnelomadeed bny t10(0H000R82E99)074i9n8 ftrohmeCopurrseoHmero.ocotmeorn s08 o-05n-
20a21 t0a7:1r5g:0e7 Gt MgTe-0n5:e00 or to another transcription
https://www.coursehero.com/file/39310168/Week-5-Case-Studiesdocx/
