Citations

The discovery of AQP4‐IgG (a pathogenic antibody that targets the astrocytic water channel aquaporin‐4), as the first sensitive and specific biomarker for any inflammatory central nervous system demyelinating disease (IDD), has shifted emphasis from the oligodendrocyte and myelin to the astrocyte as a central immunopathogenic player. Neuromyelitis optica (NMO) spectrum disorders (SDs) represent an evolving spectrum of IDDs extending beyond the optic nerves and spinal cord to include the brain (especially in children) and, rarely, muscle. NMOSD typical brain lesions are located in areas that highly express the target antigen, AQP4, including the circumventricular organs (accounting for intractable nausea and vomiting) and the diencephalon (accounting for sleep disorders, endocrinopathies, and syndrome of inappropriate antidiuresis). Magnetic resonance imaging brain abnormalities fulfill Barkoff criteria for multiple sclerosis in up to 10% of patients. As the spectrum broadens, the importance of highly specific assays that detect pathogenic AQP4‐IgG targeting extracellular epitopes of AQP4 cannot be overemphasized. The rapid evolution of our understanding of the immunobiology of AQP4 autoimmunity necessitates continuing revision of NMOSD diagnostic criteria. Here, we describe scientific advances that have occurred since the discovery of NMO‐IgG in 2004 and review novel targeted immunotherapies. We also suggest that NMOSDs should now be considered under the umbrella term autoimmune aquaporin‐4 channelopathy .

SummaryIntroductionThyroid ultrasound (US) is a widely used tool for evaluating thyroid nodules. Various US features have been suggested as predictors of thyroid cancer in children.ObjectiveTo conduct a systematic review and meta‐analysis to assess the diagnostic accuracy of different thyroid US features in detecting thyroid cancer in children.MethodsWe searched multiple online databases for cohort studies that enrolled paediatric patients with thyroid nodules (age <21 years) and evaluated the accuracy of 12 relevant ultrasound features. Diagnostic measures were pooled across studies using a random effects model.ResultsThe search strategy yielded 1199 citations, of which 12 studies met the predefined inclusion criteria (750 nodules). The prevalence of thyroid cancer was 27·2% (40·8% in patients with a history of radiation exposure and 23·2% in patients without a history of exposure to radiation). The most common cancer was papillary thyroid cancer (86·7%). The presence of internal calcifications and enlarged cervical lymph nodes were the US features with the highest likelihood ratio [4·46 (95% CI: 1·87–10·64) and 4·96 (95% CI: 2·01–12·24), respectively] for thyroid cancer. A cystic nodule was the feature with highest likelihood ratio for benign nodules [1·96 (95% CI: 0·87–4·43)].ConclusionThyroid US features are not highly accurate predictors of benign or malignant aetiology of thyroid nodules in children. Internal calcification may predict malignancy, and cystic appearance may suggest benign aetiology.