Covid without fever
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COVID-19 Without Fever: Clinical Insights and Implications
Introduction to COVID-19 Without Fever
Fever is a common symptom of COVID-19, but not all patients exhibit this symptom. Understanding the clinical presentation of COVID-19 without fever is crucial for accurate diagnosis and effective management, especially in vulnerable populations such as infants and immunocompromised individuals.
COVID-19 in Infants Without Fever
Fever Without Source (FWS) in Infants
Several studies have highlighted that COVID-19 can present as fever without a source (FWS) in infants. In a study involving infants under 90 days old, FWS was a frequent initial manifestation of SARS-CoV-2 infection. Despite the presence of fever, bacterial coinfections were rare, and inflammatory markers were not significantly elevated in infants without bacterial coinfection, indicating that COVID-19 should be considered in the differential diagnosis of FWS during the pandemic .
Clinical and Laboratory Findings
In a cohort of well-appearing febrile infants aged 30 to 90 days, COVID-19-positive infants exhibited lower hospitalization rates, shorter hospital stays, and reduced antibiotic use compared to COVID-19-negative infants. Additionally, COVID-19-positive infants had significantly lower levels of C-reactive protein (CRP), absolute neutrophil count (ANC), and white blood cell (WBC) counts, suggesting that these laboratory markers can help differentiate COVID-19 from bacterial infections in this age group.
COVID-19 in Immunocompromised Patients
Neutropenic Fever
COVID-19 can also present as neutropenic fever in immunocompromised patients. A case study described a patient with NK-cell large granular lymphocytic leukemia who presented with neutropenic fever and was subsequently diagnosed with COVID-19. Despite the neutropenia, the patient's clinical course was mild, and the use of filgrastim was effective in managing neutrophil counts without adverse events.
Fever and Leukocytosis in ECMO Patients
In patients receiving extracorporeal membrane oxygenation (ECMO) for COVID-19 or influenza, fever and leukocytosis were common but poor predictors of bacterial coinfection. This finding suggests that these parameters should not be solely relied upon for initiating infectious workups in hemodynamically stable ECMO patients.
Gut Microbiota and Immune Response
Dysbiosis and Fever
Research has shown that gut microbiota dysbiosis correlates with abnormal immune responses in moderate COVID-19 patients with fever. Patients with fever exhibited significant alterations in gut microbiome composition, with an enrichment of opportunistic pathogens like Enterococcus faecalis and Saccharomyces cerevisiae. These changes were associated with elevated inflammatory markers, indicating a potential link between gut microbiota and the severity of fever in COVID-19.
Fever Characteristics in COVID-19
Prevalence and Risk
A systematic review and meta-analysis revealed that fever is prevalent in 79.43% of adult COVID-19 patients but only in 45.86% of pediatric patients. This indicates that a significant proportion of pediatric COVID-19 cases may not present with fever, highlighting the need for vigilance in diagnosing COVID-19 in children without this symptom.
Protective Role of Fever
Emerging evidence suggests that mild fever may have a protective role in COVID-19 by inducing the production of heat shock proteins (HSP70), which can protect lung cells from inflammatory damage. However, prolonged fever does not continue to produce HSP70, and antipyretics may be beneficial after several hours of mild fever to restore the cell's ability to produce more HSP70 in subsequent fever cycles .
Conclusion
COVID-19 can present without fever, particularly in infants and immunocompromised patients. Recognizing these atypical presentations is essential for timely diagnosis and management. Laboratory markers and gut microbiota composition can provide additional insights into the disease's progression and severity. Understanding the nuanced role of fever in COVID-19 can also inform treatment strategies, potentially improving patient outcomes.
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