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Summary: Systemic thrombotic microangiopathy (TMA) is a serious condition whose early treatment is essential to reduce morbidity and mortality. TMA with only renal involvement has been associated with tyrosine kinase inhibitors, including lenvatinib, a drug used for certain advanced neoplasms. To date, TMA with systemic involvement associated with this drug has not been described. We present the case of a patient with progressive metastatic thyroid cancer who developed this complication after starting treatment with lenvatinib. We describe the signs and symptoms that led to the diagnosis and the treatment required for her recovery. Learning points: Thrombotic microangiopathy (TMA) is a group of disorders characterized by thrombosis in capillaries and arterioles due to an endothelial injury. Both, localized and systemic forms have been described.TMA with systemic involvement is characterized by hemolytic anemia, low platelets, and organ damage.Vascular endothelial growth factor signaling inhibitors have been associated with TMA, either restricted to the kidney or with systemic involvement.Lenvatinib has been rarely associated with TMA. Although only forms with isolated or predominantly renal involvement had been described so far, a predominantly systemic form can occur.Lenvatinib-induced systemic TMA must be distinguished from primary forms by measuring ADAMTS-13. Treatment includes discontinuation of the drug and supportive measures.When anemia and thrombocytopenia coexist in a patient receiving treatment with lenvatinib, a peripheral blood smear to exclude TMA is recommended.
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Objectives: Graves' disease is secondary to the presence of anti-thyrotropin receptor antibodies (TRAb), which stimulate thyroid hormones. TRab determination is crucial for etiological diagnosis. The objectives of this study were (i) to compare two methods for determining TRab by chemoluminiscence vs. standard TRACE-immunofluorescence; (ii) to determine the diagnostic validity of the three methods. Methods: A retrospective study in 194 patients with a TRAb determination request. TRAb were determined by immunofluorescence (Kryptor, ThermoFisher) and chemiluminescence (Immulite, Siemens and Maglumi, Snibe). Clinical validation: medical records were reviewed and categorized according to thyroid function. Statistical analysis: Differences in quantitative variables were assessed by intraclass correlation coefficient, Bland-Altman plot, and mean differences (mD). Qualitative variables were dichotomized by cut-off points; Kappa coefficient was calculated. Correlations were evaluated by Pearson's coefficient and Passing-Bablok regression analysis. The diagnostic validity of the three methods was investigated. Results: Kryptor-Immulite: mD: 1.2 (95%CI: -16 to >18). Passing-Bablok: Constant error (95%CI: -0.8349 to -0.5987). Proportional error (95%CI: 0.7862-1.0387). ICC: 0.86 (95%CI: 0.82-0.89). Kappa coefficient: 0.68 (95%CI 0.59-0.78). Kryptor-Maglumi: mD: -0.3 (95%CI: -12 to >12). Passing-Bablok: Constant error (95%CI: -0.7701 to >0.1621. Proportional error (95%CI: 0.8571 to 1.3179. ICC: 0.93 (95%CI: 0.89-0.97). Kappa coefficient: 0.53 (95%CI: 0.32-0.74). Diagnosis of Graves' disease was confirmed in 113 patients (Kryptorf showed better specificity and positive predictive value, whereas Immulite demonstrated better sensitivity and negative predictive value). Conclusions: The three methods have a good diagnostic performance for Graves' disease, with superimposable results on Bland-Altman plot. Interchangeability was not confirmed on the regression and agreement analysis, with the presence of biases.
