Can Influenza A (influenza type A) cause sepsis?

From the Guidelines

Yes, influenza A can cause sepsis, a life-threatening condition characterized by a dysregulated immune response to infection causing organ dysfunction, as supported by the most recent evidence from 2021 1. Influenza A virus infection can progress to severe illness that leads to sepsis, typically occurring when the initial viral infection damages the respiratory epithelium, allowing secondary bacterial infections to develop, most commonly with Streptococcus pneumoniae, Staphylococcus aureus, or Haemophilus influenzae. However, influenza itself can trigger a severe inflammatory response leading to viral sepsis without bacterial co-infection. Risk factors include extremes of age (very young or elderly), pregnancy, immunocompromised status, and underlying chronic medical conditions. Treatment involves antiviral medications like oseltamivir (Tamiflu) 75mg twice daily for 5 days, started ideally within 48 hours of symptom onset, along with supportive care including IV fluids, vasopressors if needed, and appropriate antibiotics if bacterial co-infection is suspected, as recommended by guidelines for sepsis management 1. Influenza can cause sepsis through direct viral damage to tissues, excessive inflammatory responses, and by creating conditions favorable for invasive bacterial infections. Key considerations in managing sepsis due to influenza include early recognition, prompt initiation of antimicrobial therapy, and supportive care to manage organ dysfunction, as emphasized in recent guidelines 1. Given the potential for high morbidity and mortality, it is crucial to prioritize the management of sepsis in patients with influenza, particularly those with risk factors for severe disease, and to follow the most current guidelines for sepsis management 1.

From the Research

Influenza A and Sepsis

• Influenza A can cause severe sepsis, either directly or indirectly through secondary bacterial infections 2.
• Severe sepsis is a significant concern in critically ill patients with influenza, and it is essential to understand the pathophysiological and clinical link between influenza and sepsis 2.
• Influenza A is the type most responsible for causing pandemics due to its high susceptibility to antigenic variation, which can lead to severe complications, including sepsis 3.

Clinical Manifestations and Complications

• The clinical symptoms of influenza A cannot be distinguished from those of seasonal influenza and include cough, fever, poor general status, odynophagia, and muscular aches 4.
• Influenza A infection can lead to cardiac complications, such as pericardial effusion and cardiac tamponade, which can be life-threatening if not recognized and treated promptly 5.
• Predictors of disease severity in influenza A-infected patients include neuromuscular diseases, cardiovascular diseases, subtype (H1N1) pdm09 infection, and viral load 6.

Diagnosis and Treatment

• Diagnosis of influenza A is typically made clinically, but laboratory confirmation may be useful in hospitalized patients or those with suspected influenza 3.
• Treatment with anti-influenza drugs, such as oseltamivir, may be considered if the patient presents within 48 hours of symptom onset, and annual influenza vaccination is recommended for all people six months and older 3.
• Early recognition of cardiac symptoms and appropriate diagnostic workup is crucial to avoid life-threatening complications in patients with influenza A infection 5.