Juvenile-onset systemic lupus erythematosus (jSLE) is a multisystemic disease diagnosed in young patients based on the clinical criteria of the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR). The importance of this condition lies in its greater aggressiveness compared with lupus diagnosed during adulthood (aSLE). Management, which is based on supportive care and immunosuppressive drugs, aims to reduce the overall disease activity and to prevent exacerbation. Sometimes the onset is accompanied by life-threatening clinical conditions. In this paper, we introduce three recent cases of jSLE that required admission to the Pediatric Intensive Care Unit (PICU) of a Spanish pediatric hospital. This manuscript aims to review some of the main complications associated with jSLE, such as diffuse alveolar hemorrhage, cerebral vasculitis, or an antiphospholipid syndrome; these are life-threatening conditions but they have a chance of favorable prognosis if treated early and aggressively.

Lung ultrasound (LUS) is, at present, a standard technique for the diagnosis of acute lower respiratory tract infections (ALRTI) and other lung pathologies. Its protocolised use has replaced chest radiography and has led to a drastic reduction in radiation exposure in children. Despite its undeniable usefulness, there are situations in which certain quantitative measurements could provide additional data to differentiate the etiology of some pulmonary processes and thus adapt the treatment. Our research group hypothesises that several lung processes such pneumonia may lead to altered lung tissue stiffness, which could be quantified with new diagnostic tests such as lung sono-elastography (SE). An exhaustive review of the literature has been carried out, concluding that the role of SE for the study of pulmonary processes is currently scarce and poorly studied, particularly in pediatrics. The aim of this review is to provide an overview of the technical aspects of SE and to explore its potential usefulness as a non-invasive diagnostic technique for ALRTI in children by implementing an institutional image acquisition protocol.

Background: Acute lower respiratory tract conditions are highly prevalent in paediatrics. Many of these conditions present as consolidations on imaging studies. One of the most common causes is bacterial pneumonia (BP), which requires an accurate diagnosis to implement the best treatment plan. Despite the fact that major guidelines constrain the use of invasive tests, chest X-ray (CXR) or blood tests are still routinely used for the diagnosis. In this regard, the introduction of lung ultrasound (LUS) signified an advancement in reducing the invasiveness of diagnosis. However, there are still situations where distinguishing between different aetiologies remains challenging, especially in the case of atelectasis. Methods: This is a prospective cohort study to assess the diagnostic accuracy of new non-invasive, quantifiable, and reproducible imaging biomarkers (lung elastance and microvascularization ratio) for differentiating BP from another major entity that causes the appearance of consolidation in imaging tests, atelectasis. It will be conducted at Sant Joan de Déu Hospital in Spain from June 2025 to June 2027. Firstly, imaging biomarkers will be measured in well-aerated lung tissue without consolidation to establish their values in healthy lung tissue, according to a predefined imaging acquisition protocol. Subsequently, the imaging biomarkers will be assessed in patients with confirmed lung consolidation by LUS (Group 1: BP; Group 2: atelectasis). Results: The study aims to determine whether there are statistically significant differences in the biomarker values in relation to the normal values and between the different etiological groups. Conclusions: The demonstration of the reliable diagnostic accuracy of these biomarkers could significantly reduce the need for invasive techniques and improve the therapeutic management of many patients with BP and other pulmonary conditions presenting with consolidation in imaging tests.