CASE 2 OSTEOPOROSIS

A 52 year old Caucasian woman is referred to you by an orthopedic surgeon. She has acute thoracic back pain associated with rolling over in bed the night before. An x-ray taken in his office shows an acute thoracic 8 (T8) compression fracture. Between ages 20 and 26 she had thyrotoxicosis; it was treated with radioiodine; she has been maintained on l-thyroxine. Menopause occurred at age 49. Her mother and maternal grandmother have osteoporosis. Her grandmother has had a myocardial infarction and the patient has a high-risk lipid profile.

She is 68 inches tall (maximum was 70 inches), weighs 118 pounds, had a blood pressure of 120/80 mm Hg and a regular pulse of 94 per minute. There was new dorsal kyphosis and tenderness to palpation at T8. The thyroid was not palpable.

Review of the outside x-rays confirmed the fracture at T8 and generalized demineralization of the thoracolumbar spine. The dual energy x-ray absorptiometry bone mineral density of the lumbar spine had a T score of minus 3.2 (density is 3.2 standard deviations below the mean of a similar 20 year old woman suggesting bone loss consistent with osteoporosis). Her TSH concentration was undetectable.

Her l-thyroxine maintenance dose was lowered. She was asked to mobilize as pain allowed and to walk 1.5 miles three times per week. Non-steroidal anti-inflammatory agents were recommended for pain. She was instructed on a 1500 mg elemental calcium diet with calcium citrate supplements as needed. After starting this her twenty-four hour urinary calcium excretion was low at 0.5 mg/kgm (1.5 to 4.5). 1,25(OH)2 Vitamin D3, 0.25 mcg per day, was started. This increased her urinary calcium excretion to 1.6 mg/kgm. Because of associated myocardial risk, she was asked to use conjugated equine estrogens, 0.625 mg and medroxyprogesterone acetate, 2.5 mg daily.

She returned in two years. Bone mineral density remained the same. She had taken the estrogen for one year, but stopped it because of fear that it might cause breast carcinoma. Alendronate, 10 mg daily, was prescribed. Two years later her bone mineral density had increased 6%. But during her office visit she mentioned developing esophageal pain related to a bedridden episode of the flu.

1. List some of the major risk factors for osteoporosis in this patient. 

2. What was the reason l-thyroxine was reduced in this patient? 

3. What was the significance of the low urinary calcium excretion and how does therapy with 1,25(OH)2 vitamin D3 correct this problem?

4. What are some reasons for use of hormone replacement therapy in this woman? Is therapy with estrogen and progesterone sufficient? 

5. Is the patientís concern regarding breast carcinoma valid? 

6. Discuss the benefits and side effects of alendronate used to treat osteoporosis in this patient. If she had esophageal emptying problems, would you use it?