Search

Technetium Parathyroid Scintigraphy (TS) is the most popular noninvasive localization procedure in patients with primary hyperparathyroidism (PHPT). Awareness of various factors involved in technetium uptake helps understand the outcome of TS.We utilize a case of changing TS scans in a patient to review the literature on the various biological and technical factors involved in technetium uptake by the abnormal parathyroid tissue. A 56 year female was diagnosed with PHPT and osteopenia. An initial scan using (99m)Tc-Tetrofosmin showed no definite areas of abnormal parathyroid tissue. Patient refused surgical exploration, was started on Bisphosponates and subsequently monitored. Five years later she suffered fracture of her right wrist. A repeat TS using (99m)Tc-Sestamibi revealed hypervascular parathyroid lesion in the right lower neck. She underwent successful removal of a right lower parathyroid adenoma.Technical factors like the type of Tc isotope used, imaging techniques and biological factors like biochemical parameters (calcium, vitamin D levels), adenoma size, content of oxyphilic cells, vascularity can affect the outcome of the scan.Clinicians should be aware of technical and biological factors that could result in negative scan in parathyroid nuclear scintigraphy.

Parenteral nutrition (PN) is generally given to provide adequate amounts of macronutrients and micronutrients to allow recovery after injury and illness. Maintenance of the skeleton is often neglected when one prepares a PN prescription. Although this may not be critical for the brief length of time that most patients receive PN, it becomes an important consideration in patients who need long-term PN, during which time metabolic bone disease (MBD) can develop. It is therefore important to have an understanding of the factors involved in normal bone metabolism and the impact that PN has on this process. This review describes some of the important factors that may play a role in the development of parenteral nutrition-associated metabolic bone disease (PN-MBD) and discusses a strategy for the diagnosis and treatment of this problem.