title: Use of long-term intravenous phosphate infusion in the palliative treatment of tumor-induced osteomalacia.
abstract: Tumor-induced osteomalacia is characterized by paraneoplastic defects in vitamin D metabolism, proximal renal tubular functions, and phosphate transport. The resulting hypophosphatemia can cause generalized pain and muscle weakness, which significantly affect the quality of life of the patients. Palliative treatment with calcium, vitamin D, and phosphate replacement is indicated for patients in whom the causative tumor cannot be completely resected. In this report we describe a case of tumor-induced osteomalacia in whom adequate oral doses of phosphate could not be used because of gastrointestinal side-effects. Long term (3-6 months) iv phosphate infusion delivered by ambulatory infusion pumps in combination with oral calcium and vitamin D was used successfully to decrease pain and increase muscle strength. Careful monitoring of serum calcium, phosphate, and creatinine levels and reliable microinfusion technology have allowed the long term use of iv phosphate infusion without serious morbidity. This patient received repeated (three times) phosphate infusions over 8 yr, resulting in laboratory and symptomatic improvement after each course. However, this patient did suffer two episodes of central venous catheter-related infection. Because of potentially serious complications, such as severe hypocalcemia, calcified right ventricular thrombi, and nephrocalcinosis, long term iv phosphate infusion should be reserved for patients who cannot tolerate adequate doses of oral phosphate and for whom the benefits outweigh the risks.
authors.affiliation: Section of Endocrine Neoplasia and Hormonal Disorders, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: S J
authors.initials: SJ
authors.lastname: Yeung
authors.forename: I E
authors.initials: IE
authors.lastname: McCutcheon
authors.forename: P
authors.initials: P
authors.lastname: Schultz
authors.forename: R F
authors.initials: RF
authors.lastname: Gagel
mesh_terms: D002118:Calcium / Q000627:therapeutic use; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D007260:Infusion Pumps; D007275:Injections, Intravenous; D008637:Mesenchymoma / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D008875:Middle Aged; D010018:Osteomalacia / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000209:etiology*; D010166:Palliative Care; D010710:Phosphates / Q000008:administration & dosage* / Q000627:therapeutic use; D011859:Radiography; D013125:Spinal Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology; D013997:Time Factors; D014807:Vitamin D / Q000627:therapeutic use
chemical_list: D010710:Phosphates; D014807:Vitamin D; D002118:Calcium