Anticipated effects of burosumab treatment on long-term clinical sequelae in XLH: expert perspectives

X-linked hypophosphatemia (XLH) is a rare, progressive, genetic disease with multisystem impact that typically begins to manifest in early childhood. Two treatment options exist: oral phosphate in combination with active vitamin D (“conventional therapy”) and a fully human monoclonal anti-FGF23 antibody, burosumab. The clinical benefit of conventional therapy in adults is limited, and poor tolerance and complications are common. Burosumab was first approved as a treatment for XLH in 2018 and its disease-modifying benefits in clinical trials in children suggest burosumab treatment could also alter the disease course in adults. Without long-term clinical data on multiple XLH-related sequelae available, the results of an elicitation exercise are reported, in which eight global experts in XLH posited how long-term treatment with burosumab is anticipated to impact the life course of clinical sequelae in adults with XLH. Based on their clinical experiences, the available evidence and their disease understanding, the experts agreed that some long-term benefits of using burosumab are likely in adults with XLH even if they have a misaligned skeleton from childhood. Burosumab treatment is anticipated to reduce the incidence of fractures and halt the progression of clinical sequelae associated with conventional therapy. While the trajectories for established dental abscesses are not expected to improve with burosumab treatment, dental abscess development may be prevented. Starting treatment with burosumab in childhood to increase the likelihood of an aligned skeleton and continuation into and throughout adulthood to maintain euphosphatemia may optimize patient outcomes, although future real-world investigation is required to support this hypothesis

Radioactive Iodine Administration Is Associated with Persistent Related Symptoms in Patients with Differentiated Thyroid Cancer

Context. Radioiodine (RAI) administration has adverse effects in patients treated for thyroid cancer (DTC), but there is scarce information regarding their intensity and duration. Objective. To evaluate frequency and intensity of early and late RAI-related symptoms in patients with DTC. Design. Observational prospective study. Patients. DTC patients who underwent thyroidectomy, with or without RAI. Measurements. Patients answered 2 surveys: (1) from 0 to 6 months and (2) between 6 and 18 months after initial treatment. Results. 110 patients answered the first survey and 61 both. Nearly 80 percent received RAI. Among early symptoms, periorbital edema, excessive tearing, salivary gland disturbances, dry mouth, taste disorders, and nausea were more frequent and intense among RAI patients. Regarding late symptoms, periorbital edema, salivary gland pain and swelling, and dry mouth were more frequent and intense in RAI patients. Frequency and intensity of adverse effects were not different between low and high RAI doses (50 versus ≥100 mCi). Conclusion. RAI-related symptoms are frequent and usually persist after 6 months of administration, even when low doses are given. This finding must be considered when deciding RAI administration, especially in low risk patients, among whom RAI benefit is controversial

An Expert Perspective on Phosphate Dysregulation With a Focus on Chronic Hypophosphatemia

Because of their rarity, diseases characterized by chronic hypophosphatemia can be underrecognized and suboptimally managed, resulting in poor clinical outcomes. Moreover, serum phosphate may not be measured routinely in primary care practice. Authors participated in several working sessions to advance the understanding of phosphate homeostasis and the causes, consequences, and clinical implications of chronic hypophosphatemia. Phosphate levels are regulated from birth to adulthood. Dysregulation of phosphate homeostasis can result in hypophosphatemia, which becomes chronic if phosphate levels cannot be normalized. Chronic hypophosphatemia may be underrecognized as serum phosphate measurement is not always part of routine analysis in the primary care setting and results might be misinterpreted, for instance, due to age-specific differences not being accounted for and circadian variations. Clinical consequences of chronic hypophosphatemia involve disordered endocrine regulation, affect multiple organ systems, and vary depending on patient age and the underlying disorder. Signs and symptoms of chronic hypophosphatemic diseases that manifest during childhood or adolescence persist into adulthood if the disease is inadequately managed, resulting in an accumulation of clinical deficits and a progressive, debilitating impact on quality of life. Early identification and diagnosis of patients with chronic hypophosphatemia is crucial, and clinical management should be started as soon as possible to maximize the likelihood of improving health outcomes. Furthermore, in the absence of a universally accepted description for "chronic hypophosphatemia," a definition is proposed here that aims to raise awareness of these diseases, facilitate diagnosis, and guide optimal phosphate management strategies by improving monitoring and assessment of patient response to treatment. (c) 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).Peer reviewe

Equilibrium existence in infinite horizon economies

In sequential economies with finite or infinite-lived real assets in positive net supply, we introduce constraints on the amount of borrowing in terms of the market value of physical endowments. We show that, when utility functions are either unbounded and separable in states of nature or separable in commodities, these borrowing constraints not only preclude Ponzi schemes but also induce endogenous Radner bounds on short-sales. Therefore, we obtain existence of equilibrium. Moreover, equilibrium also exists when both assets are numéraire and utility functions are quasilinear in the commodity used as numéraire.info:eu-repo/semantics/publishedVersio

Tumor-induced osteomalacia

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic syndrome clinically characterized by bone pain, fractures and muscle weakness. It is caused by tumoral overproduction of fibroblast growth factor 23 (FGF23) that acts primarily at the proximal renal tubule, decreasing phosphate reabsorption and 1α-hydroxylation of 25 hydroxyvitamin D, thus producing hypophosphatemia and osteomalacia. Lesions are typically small, benign mesenchymal tumors that may be found in bone or soft tissue, anywhere in the body. In up to 60% of these tumors, a fibronectin-1(FN1) and fibroblast growth factor receptor-1 (FGFR1) fusion gene has been identified that may serve as a tumoral driver. The diagnosis is established by the finding of acquired chronic hypophosphatemia due to isolated renal phosphate wasting with concomitant elevated or inappropriately normal blood levels of FGF23 and decreased or inappropriately normal 1,25-OH2-Vitamin D (1,25(OH)2D). Locating the tumor is critical, as complete removal is curative. For this purpose, a step-wise approach is recommended, starting with a thorough medical history and physical examination, followed by functional imaging. Suspicious lesions should be confirmed by anatomical imaging, and if needed, selective venous sampling with measurement of FGF23. If the tumor is not localized, or surgical resection is not possible, medical therapy with phosphate and active vitamin D is usually successful in healing the osteomalacia and reducing symptoms. However, compliance is often poor due to the frequent dosing regimen and side effects. Furthermore, careful monitoring is needed to avoid complications such us secondary/tertiary hyperparathyroidism, hypercalciuria, and nephrocalcinosis. Novel therapeutical approaches are being developed for TIO patients, such as image-guided tumor ablation and medical treatment with the anti-FGF23 monoclonal antibody KRN23 or anti FGFR medications. The case of a patient with TIO is presented to illustrate the importance of adequate and appropriate evaluation of patients with bone pain and hypophosphatemia, as well as an step-wise localization study of patients with suspected TIO

Spurious hypoxemia due to hyperleukocytosis. Report of one case Hipoxemia espuria por hiperleucocitosis. Reporte de un caso y revisión de la literatura

Arterial gasometry is considered the gold standard for establishing a diagnosis of respiratory failure of any etiology. However, there are some circumstances in which it loses specifi city, making necessary to consider other tests such as pulse oximetry to adequately determine hypoxemia. We report a 67 years old patient with sudden hypoacusia, right hemiparesis and polypnea. His laboratory exams on admission, showed extreme hypoxemia in several readings, without correlation to the patient's clinical condition nor the pulse oximetry, and a leukocytosis of 800.000 cells x ml, with many immature cells. Chronic myeloid leukemia was diagnosed and treatment with hydroxyurea was initiated, achieving normalization in the arterial gases in accordance with the fall of the white cell count. Interpretation of laboratory fi ndings according to the general clinical context of the patient allowed to suspect a spurious hypoxemia, saving the patient from unnecessary and risky interventions

Hypophosphatemia induced by carboxymaltose iron and imatinib. Report of two cases

Hypophosphatemia is a relatively frequent and a potentially serious adverse drug effect. Clinically it is characterized by bone pain and muscle weakness. There are several mechanisms by which a drug can induce hypophosphatemia and they can be classified according to whether or not they are mediated by an excess of Fibroblast Growth Factor 23 (FGF23). We report two patients with the condition: (i) A 49-year-old woman with Chronic Myeloid Leukemia (CML) and gastric sleeve surgery at 46 years of age. After receiving intravenous carboxymaltose iron in one occasion due to refractory anemia, she developed symptomatic hypophosphatemia. Urinary phosphate losses associated with high FGF23 levels were confirmed. Plasma phosphate returned to normal values 90 days after the iron administration. (ii) A 40-year-old man with a history of CML in whom imatinib was started. He developed symptomatic hypophosphatemia due to non FGF23-mediated hyperphosphaturia. As treatment with imatinib could not be interrupted, hypophosphatemia and its symptoms resolved with oral phosphate intake. These cases illustrate the importance of recognizing and treating drug-induced hypophosphatemia in a timely manner, and thus avoid the morbidity associated with this entity