Endocrine Case Study 2*


Linda Johnson, a 40 year-old female, reported to her family physician a three-month history of gradually progressive constipation. She told her physician that prior to three months ago, her bowel movements were normal and occurred once every day. Currently she was having only one bowel a movement every three days. Linda also told her physician that she felt cold all the time; when her family members were comfortable in a room with the thermostat set at 70°, she felt cold unless it was turned up to 74°.


Physical Examination:

Weight: 160 pounds (increase of 20 pounds from one year ago).

Height: 5 feet, 2 inches

Temperature: 96.8° F
Respirations: 12 breaths/min
Pulse: 46 beats/min
Blood Pressure 110/85

Skin: Dry without any obvious rash.

Neck: Thyroid gland mildly enlarged and non-tender.

Neurologic exam: Deep tendon reflexes such as the ankle jerks showed slight "hang-up" -- the relaxation phase seemed prolonged.

Laboratory Results

Thyroid Stimulating Hormone (TSH)=8 mU/L (normal=0.4-5 mU/L)

Thyroxine (T4)=50 nmol/L (normal-64-154 nmol/L)



1     Desribe the mechanism by which a peptide hormone initiates a cell response; a steroid hormone initiates a cell response. How are they the same? How are they different? Give a specific example of each and state their effect on the human body.


2   What are the functions of TSH and thyroxine?

3  What historical questions would you want to know regarding the patient's mood, energy level, hand pain, and voice? What answers would you anticipate to these questions?

4 What is Linda's probable diagnosis? What historical and physical exam data support this diagnosis? 


5 What do you think the patient's basal metabolic rate is: high, normal, or low? What historical or physical exam data supports your answer? What is the basal metabolic rate in most obese individuals?

6Which of the above laboratory values rule out the pituitary as a cause of Linda's problems?


7 Explain the patient's lab values in terms of a positive or negative feedback mechanism.


* adapted from A&P Clinical Case Studies

—Prepared by Marc Walters, M.D., Portland Community College