“My Brother Calls Me ‘Bug Eyes’”: A Case Study on the Endocrine System Nineteen-year-old Krista waited impatiently as Dr

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“My Brother Calls Me ‘Bug Eyes’”: A Case Study on the EndocrineSystem Nineteen-year-old Krista waited impatiently as Dr. Weismanscribbled in his chart. She hoped he was scribbling an explanationof what was wrong with her. She was tired of not feeling likeherself and tired of being so stressed about it. She wasparticularly tired of how her eyes seemed to bulge outward, so muchthat her 10-year-old brother had started calling her “Bug Eyes.”Dr. Weisman finally put down his pen and looked at Krista. “Well,your blood pressure and pulse are elevated. You’ve lost weightwithout trying, you have difficulty sleeping, you perspire morethan usual and you’ve had continuing bouts of diarrhea. Thosethings, combined with the swelling in the front of your neck,suggest that you may be suffering from more than the stress ofcollege life. I think we need to run some blood tests to check yourthyroid function.” Krista blinked in surprise. “All of those thingscan be caused by a problem with my thyroid? Even the way my eyeslook?” Dr. Weisman nodded. “Your thyroid secretes several hormonesthat have widespread and varied effects. The protrusion of youreyes is a condition called exophthalmos – it is an inflammatoryresponse to abnormal levels of thyroid hormones. The fact that youhave this condition in addition to your other symptoms makes mefairly certain this is a thyroid problem.” Krista hoped Dr. Weismanwas right. Having a medical explanation for her symptoms would meanthat she wasn’t losing her mind. Several days later, Krista metagain with Dr. Weisman. “Let’s talk about your test results,” hesaid. “Your thyroid hormone levels are elevated, but your level ofthyroid-stimulating hormone (TSH) is lower than it should be. Thoseresults suggest that you probably have Graves’ disease, which meansthat your thyroid is overactive. But there’s good news too—this isa condition that we can treat relatively easily.” Krista felt atwinge of relief at the doctor’s words, but a flurry of questionspoured out of her mouth. “What made my thyroid go crazy? And whatis TSH? If it’s a thyroid hormone, why is it low instead of highlike everything else? And what kind of treatment do I need? Will itfix my thyroid? Will I…” Dr. Weisman laughed and held up his handto stop the barrage of questions. “Hold on, Krista. I’ll explaineverything, and with the right treatment, your brother may not beable to call you ‘Bug Eyes’ much longer.”
Short Answer Questions
1. Name the two hormones commonly referred to as “thyroidhormone” and describe their general actions.
2. Why would an overactive thyroid cause Krista’s weight loss,sweating, and elevated heart rate?
3. Krista wonders if TSH is a “thyroid hormone,” and Dr. Weismanexplains that it is not. State the action of thyroid-stimulatinghormone (TSH) and name the gland that secretes it.
4. How is the secretion of TSH regulated under normalconditions?
5. In Graves’ disease, the immune system makes antibodies thatstimulate TSH receptors on the thyroid gland. What effect does thishave on Krista’s thyroid?
6. Why is Krista’s TSH level low instead of high?
7. If Krista had been diagnosed with hypothyroidism, what wouldhappen to her levels of TSH and thyroid hormone?
8. A common treatment for Graves’ disease involves ingesting adose of radioactive iodine, which slowly destroys the thyroidgland. Why are other tissues unaffected?