Severe metabolic bone disease as a long-term complication of obesity surgery

Metabolic bone disease is a well-documented long-term complication of obesity surgery. It is often undiagnosed, or misdiagnosed, because of lack of physician and patient awareness. Abnormalities in calcium and vitamin D metabolism begin shortly after gastrointestinal bypass operations; however, clinical and biochemical evidence of metabolic bone disease may not be detected until many years later.

A 57-year-old woman presented with severe hypocalcemia, vitamin D deficiency, and radiographic evidence of osteomalacia, 17 years after vertical banded gastroplasty and Roux-en-Y gastric bypass. Following these operations, she was diagnosed with a variety of medical disorders based on symptoms that, in retrospect, could have been attributed to metabolic bone disease. Additionally, she had serum metabolic abnormalities that were consistent with metabolic bone disease years before this presentation. Radiographic evidence of osteomalacia at the time of presentation suggests that her condition was advanced, and went undiagnosed for many years. These symptoms and laboratory and radiographic abnormalities most likely were a result of the long-term malabsorptive effects of gastric bypass, food intake restriction, or a combination of the two.

This case illustrates not only the importance of informed consent in patients undergoing obesity operations, but also the importance of adequate follow-up for patients who have undergone these procedures. A thorough history and physical examination, a high index of clinical suspicion, and careful long-term follow-up, with specific laboratory testing, are needed to detect early metabolic bone disease in these patients.