Hypocalcemia, hypovitaminosis d osteopathy, osteopenia, and secondary hyperparathyroidism 32 years after jejunoileal bypass.

OBJECTIVE

To detail, for the first time, the results of bone histomorphometry, micro-computed tomography, and the calcium-vitamin D-parathyroid hormone (PTH) axis in a unique patient 32 years after undergoing a jejunoileal bypass (JIB) procedure for obesity.

METHODS

A case report is presented, serial results of serum chemistry studies before and after treatment are outlined, and histomorphometric data on a bone biopsy specimen are summarized.

RESULTS

In a 65-year-old woman with chronic lymphedema who had undergone JIB >3 decades earlier, baseline serum studies showed the following: total calcium, 6.2 mg/dL (normal, 8.5 to 10.5); ionized calcium, 0.87 mmol/L (normal, 1.15 to 1.35); creatinine, 1.3 mg/dL (normal, 0.6 to 1.0); albumin, 2.0 g/dL (normal, 3.0 to 5.0); magnesium, 1.0 mg/dL (normal, 1.5 to 2.1); phosphorus, 3.1 mg/dL (normal, 2.5 to 4.5); potassium, 3.1 mEq/L (normal, 3.5 to 5.0); alkaline phosphatase, 204 U/L (normal, 50 to 136); PTH, 311 pg/mL (normal, 10 to 60); 25-hydroxyvitamin D, <7 ng/mL (normal, 10 to 60); and 1,25-dihydroxyvitamin D, 37 pg/mL (normal, 25.1 to 66.1). Histomorphometry of an undecalcified iliac crest bone biopsy specimen demonstrated increased osteoid surface of 59.4% (Z-score = 5.6), increased mineralization lag time of 90.1 days (Z-score = 2.96), decreased adjusted apposition rate of 0.05 mm3/mm2/yr (Z-score = -2.45), but increased volume-based bone formation rate of 0.715 mm3/mm3/yr (Z-score = 2.0). Tetracycline labeling was diffuse and smudged, and the osteoblast-osteoid interface was decreased, indicating a mineralization defect. Increased cortical porosity, but no evidence of significant marrow fibrosis, was noted, whereas cancellous bone volume was decreased to 15.2% (Z-score = -0.92). Micro-computed tomography of bone biopsy specimens confirmed both increased cortical porosity and decreased cancellous bone volume. Vitamin D and calcium therapy resulted in near-normal or low-normal levels of 25-hydroxyvitamin D and calcium and improvement in PTH and alkaline phosphatase levels during a 9-month period.

CONCLUSIONS

Significant hypovitaminosis D osteopathy, osteopenia, and hypocalcemia attributable to vitamin D deficiency may remain a problem in patients with unreversed JIB operations after more than 3 decades. Clinicians should be aware of this important clinical problem.