Personal Knowledge on Novel Coronavirus Pneumonia
The outbreak of novel coronavirus pneumonia, also known as COVID-19, has posed significant challenges to global health systems. Understanding the epidemiological and clinical characteristics of this disease is crucial for effective management and treatment. This article provides a comprehensive overview of the key aspects of COVID-19, including its epidemiology, clinical presentation, treatment strategies, and the role of corticosteroids in managing severe cases.
Epidemiology and Clinical Presentation
The epidemiological history of some patients infected with the novel coronavirus (2019-nCoV) remains unclear. The virus has an incubation period that can last up to two weeks or even longer. During the latent infection period or the incubation period following infection, the disease may be infectious. Similar to influenza, some patients develop only upper respiratory tract infections, while others progress to severe pneumonia. Notably, patients may not always present with fever, and symptoms can include mild cough, headache, or gastrointestinal issues. Some patients exhibit an insidious onset and slow progression, making it difficult to identify them as sick. Severe cases may present with moderate-to-low-grade fever, but apparent fever may also be absent.
Role of Corticosteroids in Treatment
The use of corticosteroids in acute respiratory distress syndrome (ARDS) and severe viral pneumonia has been a subject of extensive clinical studies. However, the efficacy of corticosteroids in reducing mortality and improving patient outcomes remains unclear. In ARDS, corticosteroids are believed to counteract hyperinflammation, excessive cell proliferation, and aberrant collagen deposition. However, evidence-based clinical research provides mixed insights. For instance, a retrospective study on severe acute respiratory syndrome (SARS) revealed that patients treated with corticosteroids had poorer outcomes, including higher risks of intensive care unit admission and increased mortality, despite being younger and having fewer underlying diseases. Similarly, corticosteroids did not improve mortality and delayed viral nucleic acid clearance in Middle East respiratory syndrome (MERS), another coronavirus-induced disease. A large meta-analysis on influenza A virus subtype H1N1 infection also indicated that corticosteroids increased mortality.
Conversely, some studies suggest that short-term corticosteroid treatment may reduce the risk of ARDS and shorten the disease duration in patients with severe community-acquired pneumonia. The use of corticosteroids in ARDS caused by Pneumocystis carinii pneumonia has gained widespread acceptance due to its potential to improve oxygenation and patient outcomes. Currently, the World Health Organization (WHO) does not recommend the routine use of systemic corticosteroids for treating viral pneumonia or ARDS, except in clinical trials. However, the “Novel Coronavirus Pneumonia Diagnosis and Treatment Protocol (5th edition, trial)” recommends short-term (3–5 days) corticosteroid treatment for severely and critically ill cases, based on a comprehensive assessment of the patient’s dyspnea level and chest imaging progression, with the dose not exceeding a methylprednisolone equivalent dose of 1 to 2 mg/kg/day. Despite these recommendations, there is insufficient evidence on the value of corticosteroids in treating COVID-19, and further high-quality randomized controlled trials (RCTs) are warranted.
ARDS and Respiratory Support
ARDS caused by 2019-nCoV appears to be more severe than typical cases. The majority of critically ill COVID-19 patients are aged 50 years and above, with many in the 70 to 80 years age group. These patients often have underlying conditions such as hypertension, diabetes, and coronary heart diseases, with some having multiple comorbidities. Clinical observations indicate that many severe patients receiving high-flow nasal cannula (HFNC) oxygen therapy or non-invasive ventilation (NIV) with a fraction of inspired oxygen (FiO2) of 1.0 have oxygenation indexes (partial pressure of arterial oxygen [PaO2]/FiO2) below 150 mmHg or even lower than 100 mmHg. Such patients require extended periods of oxygenation support, leading to prolonged hypoxic durations that can cause irreversible organ damage. Even with invasive ventilation or extracorporeal membrane oxygenation (ECMO), the success rate of resuscitation in these patients remains very low.
The WHO’s interim guidance suggests that HFNC and NIV should only be used in selected patients with hypoxemic respiratory failure, and these patients should be closely monitored for clinical deterioration. If the oxygenation index remains below 100 mmHg after 24 hours of invasive ventilation with high positive end-expiratory pressure in the prone position, ECMO should be promptly initiated. This recommendation aligns with the guidelines of the Chinese Society of Extracorporeal Life Support. The “Novel Coronavirus Pneumonia Diagnosis and Treatment Protocol (5th edition, trial)” also emphasizes that endotracheal intubation and invasive mechanical ventilation should be performed promptly if the patient’s condition does not improve or deteriorates within a short period (1–2 hours) when using HFNC or NIV. If invasive mechanical ventilation in the prone position is ineffective, ECMO should be considered as early as possible.
Supportive Treatment and Antiviral Drugs
Supportive treatment remains the mainstay for managing COVID-19. Ensuring adequate respiratory support is crucial to prevent hypoxia and protect other organs. Currently, there are no effective antiviral drugs for COVID-19, and antimicrobial drugs should be administered strictly and rationally. Some traditional Chinese medicines, such as Shuanghuanglian, have demonstrated inhibitory effects against the virus in in vitro experiments. However, their clinical efficacy remains unknown, and further investigations are required to validate their effectiveness.
In conclusion, the management of COVID-19 requires a comprehensive understanding of its epidemiological and clinical characteristics. The role of corticosteroids in treating severe cases remains controversial, and further research is needed to establish their efficacy. Supportive respiratory care is essential, and the timely use of advanced respiratory support methods, including ECMO, can be life-saving in critically ill patients. As the global medical community continues to learn more about this novel disease, ongoing research and clinical trials will be crucial in developing effective treatment strategies.
doi.org/10.1097/CM9.0000000000000757
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