Clinical Overview > Hormone > FGF23
You are looking at 1 - 4 of 4 items
Search for other papers by Eseoghene Ifie in
Google Scholar
PubMed
Search for other papers by Samson O Oyibo in
Google Scholar
PubMed
Search for other papers by Hareesh Joshi in
Google Scholar
PubMed
Search for other papers by Olugbenro O Akintade in
Google Scholar
PubMed
Summary
Iron (ferric carboxymaltose) infusion therapy is used to treat severe iron deficiency which is not responding to the first-line oral iron therapy. However, it can also cause severe renal wasting of phosphate resulting in severe hypophosphataemia in some patients. Despite the growing number of case reports, this side effect is not well known to healthcare professionals. The product labelling information sheet does mention that hypophosphataemia can be a side effect, but also says that this side effect is usually transient and asymptomatic. We report a challenging case of a patient who developed severe, symptomatic and prolonged hypophosphataemia after an intravenous iron infusion for severe iron deficiency.
Learning points:
-
Clinicians prescribing ferric carboxymaltose (Ferinject®) should be aware of the common side effect of hypophosphataemia, which could be mild, moderate or severe.
-
Patients receiving iron infusion should be educated concerning this potential side effect.
-
Pre-existing vitamin D deficiency, low calcium levels, low phosphate levels or raised parathyroid hormone levels may be risk factors, and these should be evaluated and corrected before administering intravenous iron.
-
Patients may require phosphate and vitamin D replacement along with monitoring for a long period after iron infusion-induced hypophosphataemia.
-
Every incident should be reported to the designated body so that the true prevalence and management thereof can be ascertained.
Search for other papers by Zaina Adnan in
Google Scholar
PubMed
Search for other papers by David Nikomarov in
Google Scholar
PubMed
Search for other papers by Michal Weiler-Sagie in
Google Scholar
PubMed
Search for other papers by Noga Roguin Maor in
Google Scholar
PubMed
Summary
Phosphaturic mesenchymal tumor (PMT) represents a rare cause of osteomalacia. The clinical signs and symptoms are vague and these lead to diagnosis delay. In the presence of hypophosphatemia and relatively high urine phosphate excretion, this entity should be taken into consideration in the deferential diagnosis of osteomalacia. In the present article, we report 81-year-old man presented to our clinic for evaluation due to osteopenia. His laboratory results disclosed hypophosphatemia, relatively increased urine phosphate excretion and increased level of intact fibroblast growth factor 23 (FGF23). A 68Gallium DOTATATE PET/CT revealed pathological uptake in the upper aspect of the left shoulder adjacent to the coracoid process. For suspected PMT a wide resection of the tumor was performed and pathological findings were consistent for PMT. Laboratory tests were normalized postoperatively. Reviewing the literature, we had identified 33 reported cases of PMTs among elderly patients age ≥70 years. Unlike previously reported data, where tumors predominantly localized in the lower extremities and pelvis, our search disclosed a high rate of tumor localization (10 cases – 33.3%) in the head with equal number of tumors (14 cases – 42.4%) localized in the head and upper extremity as well as in pelvis and lower extremity. The present case describes unique tumor localization in an elderly patient and our literature search demonstrated for the first time a high rate of tumor localization in the head among this group of patients.
Learning points:
-
PMTs represent a rare entity that should be considered in the differential diagnosis of elderly patients presented with persistent hypophosphatemia.
-
Unlike previously reported data, head and neck tumor localization is frequent among elderly patients.
-
68Gallium-conjugated somatostatin peptide analogs, such as 68Ga-DOTATATE PET/CT demonstrated the greatest sensitivity and specificity for tumor localization in patients with phosphaturic mesenchymal tumors (PMTs).
-
Wide tumor resection using intraoperative ultrasound is of major importance in order to ensure long-term cure.
Endocrinology, Rheumatology/Immunology, Klinikum Südstadt Rostock, Rostock, Germany
Search for other papers by Hans-Christof Schober in
Google Scholar
PubMed
Search for other papers by Christian Kneitz in
Google Scholar
PubMed
Search for other papers by Franziska Fieber in
Google Scholar
PubMed
Endocrinology, Rheumatology/Immunology, Klinikum Südstadt Rostock, Rostock, Germany
Search for other papers by Kathrin Hesse in
Google Scholar
PubMed
Search for other papers by Henry Schroeder in
Google Scholar
PubMed
Summary
Tumor-induced osteomalacia (TIO) is caused by the hormone fibroblast growth factor 23 (FGF-23). It is mainly produced in the tissue of mesenchymal tumors. Patients with TIO frequently suffer from a chronic decompensated pain syndrome and/or muscle weakness with postural deformity. Despite the severity of the disease, the diagnosis is frequently established late. In some cases, it takes several years to establish the condition. This case report concerning a 68-year old woman demonstrates the selective blood sampling for FGF-23 as path-breaking diagnostics to confirm the diagnosis of a neuroendocrine tumor.
Learning points:
-
Tumor-induced osteomalacia is a rare condition compared to other paraneoplastic syndromes.
-
It causes complex symptoms such as progressive reduction of physical capacity, exhaustion, fatigue, a decompensated pain syndrome of the musculoskeletal system and fractures of several bones.
-
Elevated serum levels of FGF-23 implicate massive phosphate elimination and resulting hypophosphatemia.
-
The diagnosis is often established over a period of several years because the localization of small FGF-23-producing tumors is complicated.
-
It is the combination of MRI and selective blood sampling for FGF-23 which permits reliable identification of tumors causing TIO and leads to accurate localization.
-
In a patient with generalized pain and reduced physical capacity, osteological parameters such as phosphate, 25-OH vitamin D3 and 1,25-(OH)2D3, as well as bone-specific alkaline phosphatase levels in serum should be determined. Hypophosphatemia should always lead to further diagnostic investigations aiming at the detection of an FGF-23-producing tumor.
Search for other papers by Shintaro Kawai in
Google Scholar
PubMed
Search for other papers by Hiroyuki Ariyasu in
Google Scholar
PubMed
Search for other papers by Yasushi Furukawa in
Google Scholar
PubMed
Search for other papers by Reika Yamamoto in
Google Scholar
PubMed
Search for other papers by Shinsuke Uraki in
Google Scholar
PubMed
Search for other papers by Ken Takeshima in
Google Scholar
PubMed
Search for other papers by Kenji Warigaya in
Google Scholar
PubMed
Search for other papers by Yuji Nakamoto in
Google Scholar
PubMed
Search for other papers by Takashi Akamizu in
Google Scholar
PubMed
Summary
Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome characterized by renal phosphate wasting leading to hypophosphatemia due to excessive actions of fibroblast growth factor 23 (FGF23) produced by the tumors. Although the best way of curing TIO is complete resection, it is usually difficult to detect the culprit tumors by general radiological modalities owing to the size and location of the tumors. We report a case of TIO in which the identification of the tumor by conventional imaging studies was difficult. Nonetheless, a diagnosis was made possible by effective use of multiple modalities. We initially suspected that the tumor existed in the right dorsal aspect of the scapula by 68Ga-DOTATOC positron emission tomography/computed tomography (68Ga-DOTATOC-PET/CT) and supported the result by systemic venous sampling (SVS). The tumor could also be visualized by 3T-magnetic resonance imaging (MRI), although it was not detected by 1.5T-MRI, and eventually be resected completely. In cases of TIO, a stepwise approach of 68Ga-DOTATOC-PET/CT, SVS and 3T-MRI can be effective for confirmation of diagnosis.
Learning points:
-
TIO shows impaired bone metabolism due to excessive actions of FGF23 produced by the tumor. The causative tumors are seldom detected by physical examinations and conventional radiological modalities.
-
In TIO cases, in which the localization of the culprit tumors is difficult, 68Ga-DOTATOC-PET/CT should be performed as a screening of localization and thereafter SVS should be conducted to support the result of the somatostatin receptor (SSTR) imaging leading to increased diagnosability.
-
When the culprit tumors cannot be visualized by conventional imaging studies, using high-field MRI at 3T and comparing it to the opposite side are useful after the tumor site was determined.
