Hyponatremia, the most frequent electrolyte disorder, is caused predominantly by the syndrome of inappropriate antidiuresis (SIAD). A comprehensive characterization of SIAD subtypes, defined by type of osmotic dysregulation, is lacking, but may aid in predicting therapeutic success. Here, we analyzed serial measurements of serum osmolality and serum sodium, plasma arginine vasopressin (AVP), and plasma copeptin concentrations from 50 patients with hyponatremia who underwent hypertonic saline infusion. A close correlation between copeptin concentrations and serum osmolality existed in 68 healthy controls, with a mean osmotic threshold6SD of 28264 mOsM/kg H 2 O. Furthermore, saline-induced changes in copeptin concentrations correlated with changes in AVP concentrations in controls and patients. With use of copeptin concentration as a surrogate measure of AVP concentration, patients with SIAD could be grouped according to osmoregulatory defect: Ten percent of patients had grossly elevated copeptin concentrations independent of serum osmolality (type A); 14% had copeptin concentrations that increased linearly with rising serum osmolality but had abnormally low osmotic thresholds (type B); 44% had normal copeptin concentrations independent of osmolality (type C), and 12% had suppressed copeptin concentrations independent of osmolality (type D). A novel SIAD subtype discovered in 20% of patients was characterized by a linear decrease in copeptin concentrations with increasing serum osmolality (type E or "barostat reset"). In conclusion, a partial or complete loss of AVP osmoregulation occurs in patients with SIAD. Although the mechanisms underlying osmoregulatory defects in individual patients are presumably diverse, we hypothesize that treatment responses and patient outcomes will vary according to SIAD subtype.

BackgroundSomatostatin receptor (SSTR)–targeted PET/CT is used for patients affected with small cell lung cancer (SCLC), but the clinical impact has not been elucidated yet. We aimed to determine whether SSTR PET/CT can trigger relevant therapeutic management changes in patients with SCLC and whether those modifications achieve disease control and are associated with prolonged survival.MethodsOne hundred patients with SCLC received SSTR PET/CT. In a retrospective setting, we evaluated the diagnostic performance of PET versus CT and compared therapies before and after PET/CT to determine the impact of molecular imaging on treatment decision. We also determined the rate of disease control after therapeutic modifications and assessed survival in patients with and without changes in the therapeutic regimen.ResultsRelative to CT, SSTR PET alone was superior for assessing bone lesions in 19 of 39 instances (49%). Treatment was modified in 59 of 100 (59%) after SSTR PET/CT. Forty of 59 (74.6%) received systemic treatment after hybrid imaging, with the remaining 15 of 59 (25.4%) scheduled for nonsystemic therapy. In the latter group, 13 of 15 (86.7%) received local radiation therapy or active surveillance (2/15 [13.3%]). Individuals scheduled for systemic treatment after imaging received peptide receptor radionuclide therapy (PRRT) in 28 of 44 (63.6%), followed by chemotherapy in 10 of 44 (22.7%), change in chemotherapy regimen in 3 of 44 (6.8%), and initiation of tyrosine kinase inhibitor in the remaining 3 of 44 (6.8%). Among patients with modified treatment, follow-up was available in 53 subjects, and disease control was achieved in 14 of 53 (26.4%). However, neither change to systemic treatment (155 days; hazard ratio, 0.94; 95% confidence interval, 0.53–1.67) nor change to nonsystemic treatment (210 days; hazard ratio, 0.67; 95% confidence interval, 0.34–1.34) led to a prolonged survival when compared with subjects with no change (171 days, P ≥ 0.22, respectively).ConclusionsIn patients with SCLC, SSTR-targeted hybrid imaging provides complementary information on the disease status. PET/CT led to management changes in 59% (mainly PRRT), achieving disease control in >26%. The high fraction of patients scheduled for PRRT may lay the foundation for combination strategies to achieve synergistic antitumor effects, for example, by combining PRRT plus recently introduced RNA polymerase II inhibitors.

BackgroundLittle is known about knowledge, attitudes and behaviors concerning Chagas disease (CD) among Latin American migrants in Germany to inform public health decision making.MethodsA cross-sectional, questionnaire-based study was conducted between March 2014 and October 2019 among Latin American migrants in six cities in Germany to obtain information on migration history, socioeconomic and insurance status, knowledge about CD, potential risk factors for Trypanosoma cruzi infection, and willingness to donate blood or organs.Results168 participants completed the questionnaire. The four countries with the highest proportion of participants contributing to the study population were Colombia, Mexico, Peru and Ecuador. Before migrating to Europe, the majority of the study population resided in an urban setting in houses made of stone or concrete, had higher academic education and was integrated into the German healthcare and healthcare insurance system. The majority of all study participants were also willing to donate blood and organs and a quarter of them had donated blood previously. However, many participants lacked basic knowledge about symptoms and modes of transmission of Chagas disease. One out of 56 serologic tests (1.8%) performed was positive. The seropositive female participant born in Argentina had a negative PCR test and no signs of cardiac or other organ involvement.ConclusionsThe study population does not reflect the population structure at risk for T. cruzi infection in endemic countries. Most participants had a low risk profile for infection with T. cruzi. Although the sample size was small and sampling was not representative of all persons at risk in Germany, the seroprevalence found was similar to studies previously conducted in Europe. As no systematic screening for T. cruzi in Latin American blood and organ donors as well as in women of child-bearing age of Latin American origin is implemented in Germany, a risk of occasional transmission of T. cruzi remains.

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