A Linda is a 52-year-old mother of two who was diagnosed with rheumatoid arthritis (RA) 8 years ago. Since then, she has been taking prednisone, a synthetic glucocorticoid, to minimize the inflammatory effects of the disease. Over the course of her treatment, Linda's physician has gradually had to increase her daily dose of prednisone. Linda has developed a "pot-belly," a rounder face, and more facial hair. Concerned about these changes, she visits her physician, who completes an examination. While updating the patient history, the physician learns that Linda has also noticed that she bruises easily. The physician tells Linda that her symptoms are probably related to the use of prednisone rather than to another disease. Blood samples are drawn, and the physician asks Linda to return in a week. At her next appointment, Linda is informed that, with the exception of RA, she is in good health, with no sign of any other disease. The physician tells her that the changes she is noticing will continue unless she stops or reduces her intake of prednisone. Also, additional effects of the prednisone could develop over time, such as acne, muscle wasting, thinning hair, and a slight hump on her back. After further discussion, Linda and her physician decide to gradually reduce the amount of prednisone she is taking and switch to other anti-inflammatory agents to control her RA symptoms. a
1. The signs caused by Linda's use of prednisone mimic those of endocrine disease. Identify that disease.
2. What signs or symptoms of that disease would you predict that Linda will not exhibit? Why not?
3. What other side effects would you expect prednisone to have? Explain them.
4. Based on your understanding of the regulation of hormone receptors, explain why the physician would recommend a gradual withdrawal of prednisone and not an abrupt cessation of its use.
5. Describe how prednisone would affect the secretion of ACTH and cortisol.
6. Based on what you know of the network of controls over endocrine gland function, explain why the ACTH level is elevated in Addison disease.
7. People with growth hormone hypersecretion may develop diabetes mellitus as a side effect. Would you expect this diabetes to be type I (IDDM) or type II (NIDDM)? Explain your reasoning.
8. Explain why people with growth hormone hypersecretion may exhibit an enlarged sella turcica on X-ray.
9. Normally, when a person is well hydrated, he or she does not feel thirsty. In SIADH, a person is over-hydrated and yet feels intensely thirsty. Explain your reasoning!