RESUMO
Chronic bone loss is an under-recognized complication of malaria, the underlying mechanism of which remains incompletely understood. We have previously shown that persistent accumulation of Plasmodium products in the bone marrow leads to chronic inflammation in osteoblast (OB) and osteoclast (OC) precursors causing bone loss through MyD88, an adaptor molecule for diverse inflammatory signals. However, the specific contribution of MyD88 signaling in OB or OC precursors in malaria-induced bone loss remains elusive. To assess the direct cell-intrinsic role of MyD88 signaling in adult bone metabolism under physiological and infection conditions, we used the Lox-Cre system to specifically deplete MyD88 in the OB or OC lineages. Mice lacking MyD88 primarily in the maturing OBs showed a comparable decrease in trabecular bone density by microcomputed tomography (µCT) to that of controls after PyNL infection. In contrast, mice lacking MyD88 in OC precursors showed significantly less trabecular bone loss than controls, suggesting that malaria-mediated inflammatory mediators are primarily controlled by MyD88 in the OC lineage. Surprisingly, however, depletion of MyD88 in OB, but not in OC precursors, resulted in reduced bone mass with decreased bone formation rates in the trabecular areas of femurs under physiological conditions. Notably, IGF-1, a key molecule for OB differentiation, was significantly lower locally and systemically when MyD88 was depleted in OBs. Thus, our data demonstrate an indispensable intrinsic role for MyD88 signaling in OB differentiation and bone formation, while MyD88 signaling in OC lineages plays a partial role in controlling malaria-induced inflammatory mediators and following bone pathology. These findings may lead to the identification of novel targets for specific intervention of bone pathologies, particularly in malaria-endemic regions.
RESUMO
Background: Bone and joint infections are common in children, particularly those under 10 years of age. While antimicrobial therapy can often successfully treat these infections, surgical drainage may also be necessary. It is important to note that prolonged courses of treatment have been associated with adverse events and drug reactions. Among these, drug reactions with eosinophilia and systemic symptoms (DRESS) syndrome is particularly severe and potentially life-threatening. We aimed to evaluate the cases of DRESS syndrome that develop during the treatment of bone and joint infections. Methods: A retrospective study was conducted at a tertiary-level university hospital between 2015 and 2022 to determine the incidence and outcomes of definite DRESS Syndrome in children under 18 years of age with bone and joint infections. Results: Of 73 patients with bone and joint infections, 16 (21.9 %) children developed antimicrobial therapy-induced DRESS syndrome. Eight (50 %) of these children were boys; the mean age of the patients was 9.76 ± 5.5 years. DRESS syndrome occurred in 16 children, including 13 children with osteomyelitis, 1 child with osteomyelitis and septic arthritis, and 2 children with septic arthritis and sacroiliitis. The mean duration of intravenous antibiotic therapy was 40.6 ± 16.6 days; the mean hospital stay was 48.7 ± 23.7 days; the mean time for the development of DRESS syndrome after starting antibiotics was 19.6 ± 7.68 days. New onset fever (68.8 %) and rash (43.8 %) were the most common symptoms of DRESS Syndrome. Cefotaxime and vancomycin were drugs responsible for DRESS syndrome in 8 (50 %) of 16. The causative antibiotics were switched to another class of antibiotic, most commonly preferred was ciprofloxacin (n:5; 31.3 %). For children with persistent symptoms, steroids were used in 5 (31.25) patients. Conclusions: Clinicians should be aware of DRESS syndrome in children who develop fever and rash under long-term antibiotics and should check hematological and biochemical parameters to predict the severity of DRESS syndrome. In patients with persistent symptoms, steroids may be used to control the symptoms.
RESUMO
BACKGROUND: This study focused on timelines of infection episodes and dominant variants and aims to determine disease severity and outcome of pediatric patients with reinfection. MATERIALS AND METHODS: This study retrospectively evaluated the medical records of the hospitalized patients and/or outpatients aged 0-18 with a positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction between March 2020 and September 2022 at Ege University Children's Hospital. RESULTS: Ninety-one pediatric patients reinfected with SARS-CoV-2 were included in the study. There was an underlying disease in 26.4% of the patients. The median time between the two infection episodes was 184 (90-662) days. There were 24 patients (26.3%) with the first infection in pre-Delta period; 17 (18.6%) of them were reinfected in Omicron BA.1 period, while 7 (7.6%) in Omicron BA.4/BA.5 period. Forty-five patients (49.4%) were infected initially in the Delta period; 35 patients (38.4%) were reinfected in the Omicron BA.1 period, while 10 patients (10.9%) were reinfected in the Omicron BA.4/BA.5 period. Twenty-two patients (24.1%) had the first infection in the Omicron BA.1 period and then reinfected in the Omicron BA.4/BA.5 period. Patients with reinfection more frequently displayed a symptom (84.6% vs. 94.5%, p = 0.03). The hospitalization rate significantly declined in reinfection (15.3% vs. 7.6%, p = 0.03). Severe disease, treatment needs and steroid use were decreased in reinfections without a significant difference (p > 0.05). Intensive care unit admission was not altered. CONCLUSION: This study revealed that reinfections frequently develop in previously healthy children but do not cause more severe outcomes. The risk of symptomatic reinfections is still high due to the effect of the Omicron variant.