Introduction: Adult Onset Still´s Disease (AOSD) is a rare systemic inflammatory disease of unclear etiology, with low incidence and prevalence among the general population. AOSD is a common cause of fever of unknown origin (FUO) in up to 20% of cases. Due to the scarce knowledge about this disease and its diagnosis, it is usually unrecognized in the differential diagnoses, worsening the prognosis and increasing complications in some patients.Case presentation: This is the case of a 32-year-old female patient with prolonged febrile illness, who did not respond to the antimicrobial treatments previously established. She was diagnosed with AOSD according to the Yamaguchi criteria after an extensive exclusion process. She was treated with first-line treatment with corticosteroids, achieving satisfactory results.Conclusions: The diagnosis of AOSD is an exhaustive process. Regardless of the availability of cutting-edge diagnostic tools, the medical history of the patient and an adequate physical examination are the most important aspects to consider.

Immune thrombocytopenia (ITP) is an autoimmune hematological condition characterized by a markedly isolated decrease in platelets without any apparent associated clinical conditions, resulting in bleeding and bruising of the skin, mucous membranes, and major organs. It is often triggered by preceding illness or several immune stimulants such as immunizations, infections, allergic reactions, among others. While uncommon, arthropod bites can trigger acute ITP. Four cases have been reported due to bee stings and insect bites, as well as a case of ITP following honeybee-venom therapy. Here, we report a case of acute ITP possibly triggered by multiple tick bites.

This study aimed to assess the diagnostic utility of VIDAS^® DENGUE NS1 Ag and anti-DENV IgM and IgG assays in parallel for an early and accurate diagnosis and classification of dengue virus (DENV) infection. For this retrospective cross-sectional study, 190 patients with suspected dengue were tested using VIDAS^® NS1, IgM, and IgG assays, requested in parallel, regardless of symptom onset timing, and classified into primary and secondary infections. Results were analyzed to determine diagnostic accuracy and correlation with disease severity. Parallel testing effectively differentiated between primary and secondary DENV infection. Secondary dengue cases with warning signs showed significantly elevated IgG levels (p = 0.026). Notably, NS1-negative (possible secondary cases) had higher IgM and IgG levels than NS1-positive cases (p < 0.01), suggesting that NS1 negativity might indicate an amplified immune response. In conclusion, VIDAS^® Dengue diagnostic assays not only enhance the diagnostic accuracy of dengue infection but also offer valuable insights into serological patterns, especially in secondary cases. These assays could be used not only to confirm diagnosis but also to stratify patients by risk, particularly in cases of secondary dengue, where IgG levels might indicate a higher risk for severe outcomes.

An 18-year-old Colombian male soldier was referred to our institution for a febrile illness that had progressively worsened over 8 days. His symptoms included fever, general malaise, cough, and hemoptysis, which progressed to respiratory distress, necessitating orotracheal intubation. Chest radiography revealed diffuse bilateral mixed opacities ( Figure 1A). A complete blood count showed leukocytosis and neutrophilia, and blood biochemistry showed elevated creatine and phosphokinase levels. Both a rapid IgM test and an IgM ELISA were positive for Leptospira. High-resolution chest computed tomography ( Figure 2A and 2B ) revealed a classic pattern of diffuse alveolar hemorrhage, which was subsequently confirmed by bronchoscopy and bronchoalveolar lavage. We initiated ceftriaxone and methylprednisolone pulse therapy at a dose of 1000 mg/day for 3 days, followed by 1 mg/kg/day for 7 days. After treatment, the patient’s clinical condition rapidly improved, enabling successful weaning from mechanical ventilation ( Figure 1B). A serum sample collected on day 8 of illness was retrospectively tested using a microscopic agglutination test, which yielded a positive result for Leptospira kirschneri serogroup Cynopteri with a dilution of 1:3,200.