Refractory Hypocalcemia Following Stomach Intestinal Pylorus-Sparing Bariatric Surgery and Thyroidectomy: Successful Management With Creation of a Proximal Roux-en-Y Gastric Bypass

Some forms of bariatric surgery make patients susceptible to calcium malabsorption, and the parathyroid hormone (PTH) axis is important for maintaining normocalcemia in these patients. Injury to the parathyroid glands due to anterior neck surgery commonly causes PTH axis disruption and can result in severe hypocalcemia in bariatric surgery patients. Herein, we present a case of a patient with a history of stomach intestinal pylorus-sparing bariatric surgery who developed refractory hypocalcemia requiring daily intravenous (IV) calcium 2 years after thyroidectomy. PTH levels were inappropriately normal during episodes of hypocalcemia, and urinary calcium level was <3.0 mg/dL following large oral doses of calcium, suggesting that both inadequate PTH response and malabsorption contributed to her severe hypocalcemia. In order to enhance calcium absorptive capacity while minimizing the risk of weight regain, she was surgically treated with a Roux-en-Y gastric bypass proximal to the prior operation. The surgery successfully improved blood calcium levels; the patient was successfully weaned from IV calcium and was able to maintain normocalcemia with oral supplements. We discuss the case in the context of available literature and provide our recommendations.

The Science of History: Why the Egyptians Never Smiled for Pictures [NYU School of Medicine, New York Institute of Technology, Stony Brook School of Medicine]

The Ancient Nubians have historically been renowned for their significant contributions to medicine. In spite of this, extremely poor oral health plagued this population. Paleopathological studies depict pronounced dental deterioration patterns far exceeding normal physiological progression. The advanced wear is popularly attributed to sand particle contamination of their daily diets. However, considering that individual wear mechanisms rarely act in isolation, we propose that adverse biochemical factors arising from regular consumption of tetracycline- fortified beer induced calcium malabsorption, and thus provided a synergistic diathesis in potentiating these effects. We examine these implications within the context of prevalent therapeutic remedies, bone fluorescence labeling data, and sociocultural attitudes when making the link between tetracycline and the compromised integrity of teeth, while citing the emergence of antibiotics actually predating formally-accepted convention.

Roux-en-Y gastric bypass surgery reduces bone mineral density and induces metabolic acidosis in rats

Roux-en-Y gastric bypass (RYGB) surgery leads to bone loss in humans, which may be caused by vitamin D and calcium malabsorption and subsequent secondary hyperparathyroidism. However, because these conditions occur frequently in obese people, it is unclear whether they are the primary causes of bone loss after RYGB. To determine the contribution of calcium and vitamin D malabsorption to bone loss in a rat RYGB model, adult male Wistar rats were randomized for RYGB surgery, sham-operation–ad libitum fed, or sham-operation–body weight-matched. Bone mineral density, calcium and phosphorus balance, acid-base status, and markers of bone turnover were assessed at different time points for 14 wk after surgery. Bone mineral density decreased for several weeks after RYGB. Intestinal calcium absorption was reduced early after surgery, but plasma calcium and parathyroid hormone levels were normal. 25-hydroxyvitamin D levels decreased, while levels of active 1,25-dihydroxyvitamin D increased after surgery. RYGB rats displayed metabolic acidosis due to increased plasma lactate levels and increased urinary calcium loss throughout the study. These results suggest that initial calcium malabsorption may play a key role in bone loss early after RYGB in rats, but other factors, including chronic metabolic acidosis, contribute to insufficient bone restoration after normalization of intestinal calcium absorption. Secondary hyperparathyroidism is not involved in postoperative bone loss. Upregulated vitamin D activation may compensate for any vitamin D malabsorption.

Bone Mineralization in Celiac Disease

Evidence indicates a well-established relationship between low bone mineral density (BMD) and celiac disease (CD), but data on the pathogenesis of bone derangement in this setting are still inconclusive. In patients with symptomatic CD, low BMD appears to be directly related to the intestinal malabsorption. Adherence to a strict gluten-free diet (GFD) will reverse the histological changes in the intestine and also the biochemical evidence of calcium malabsorption, resulting in rapid increase of BMD. Nevertheless, GFD improves BMD but does not normalize it in all patients, even after the recovery of intestinal mucosa. Other mechanisms of bone injury than calcium and vitamin D malabsorption are thought to be involved, such as proinflammatory cytokines, parathyroid function abnormalities, and misbalanced bone remodeling factors, most of all represented by the receptor activator of nuclear factor B/receptor activator of nuclear factor B-ligand/osteoprotegerin system. By means of dual-energy X-ray absorptiometry (DXA), it is now rapid and easy to obtain semiquantitative values of BMD. However, the question is still open about who and when submit to DXA evaluation in CD, in order to estimate risk of fractures. Furthermore, additional information on the role of nutritional supplements and alternative therapies is needed.

Semiquantitative Assessment of Bowel Habits and Its Relation with Calcium Metabolism after Gastric Bypass Surgery: A Retrospective Study

Background. Calcium malabsorption after bariatric surgery may be harmful to skeletal health and demands for optimal skeletal management.Methods. 103 Patients were evaluated retrospectively at 12 months after surgery. The evaluation included a questionnaire about stool frequency and consistency and laboratory assessments.Results. 103 Patients, 27 males and 76 females, were included in the study. 83 Patients had an alimentary limb of 100 cm and 20 patients one of 150 cm. At 12 months after surgery, 77.7% reported changes of bowel habits, albumin adjusted calcium levels were normal in all but 2 patients, and PTH levels were increased in 35%. Correlations between semiquantified bowel scores (fecal scores) and data from the laboratory demonstrated increasing PTH values along with more frequent and softer/watery stools (RR 30.5, CI 6.2–149.2,P<.001). There was a trend for higher PTH levels in patients with an alimentary limb of 150 cm. Normal PTH levels were more frequently found in case of calcium and vitamin D3 use (RR 14.3, CI 3.6–56.5,P<.001).Conclusion. This study demonstrates interrelationships between semi-quantified fecal scores, PTH levels, and the compliance of taking calcium/vitamin D3 suppletion. However, prospective randomized studies are necessary to show causal relationships.