What is viral pneumonia?

"Pneumonia" strictly refers to any inflammatory disease involving the lung parenchyma (including the visceral pleura, connective tissue, airways, alveoli, and vascular structures).

It typically manifests as fever, cough, sputum production, abnormal breathing, and other symptoms, along with lung parenchymal involvement (evidenced by fixed moist rales on auscultation or pulmonary infiltrates on chest X-ray).

Pneumonia caused by viruses reaching the lungs through minor aspiration from the upper respiratory tract or by downward spread of upper respiratory viral infections is called viral pneumonia.

Which department should I visit for viral pneumonia?

English name: Virus pneumonia.

Aliases: Viral lung infection, viral infectious pneumonia.

Departments: Respiratory Medicine, Pediatric Respiratory Medicine, Pediatrics, Infectious Diseases, Infectious Diseases & Contagious Diseases.

What causes viral pneumonia?

Viral pneumonia mostly occurs in winter and spring and can spread through respiratory droplets (aerosols, droplet nuclei, dust) or direct contact. It often spreads quickly and widely.

1. Common pathogenic viruses include influenza A and B viruses, adenovirus, parainfluenza virus, respiratory syncytial virus, rhinovirus, and coronavirus. Patients may be infected by one or more of these viruses and may also develop secondary bacterial (e.g., Staphylococcus aureus) or fungal infections (common in immunocompromised patients).
2. Immunocompromised patients are susceptible to herpesvirus and measles virus pneumonia.
3. Bone marrow and organ transplant recipients are prone to herpesvirus and cytomegalovirus pneumonia.

Who is most at risk for viral pneumonia?

Both immunocompetent and immunocompromised individuals can develop viral pneumonia, but the incidence is higher in children than adults, and higher in infants than older children.

Immunocompromised infants, elderly individuals, those with chronic cardiopulmonary diseases, or pregnant women often experience more severe symptoms, which can sometimes be fatal.

What are the symptoms of viral pneumonia?

Most patients with viral pneumonia have mild symptoms (similar to mycoplasma pneumonia, sometimes difficult to distinguish), but a few may develop severe symptoms.

1. Most patients have an acute onset, with prominent systemic symptoms such as fever, headache, body aches, and fatigue, followed by respiratory symptoms like cough, white sticky sputum, sore throat, and rapid breathing.
2. A small number of patients (mostly children or the elderly) may develop severe pneumonia, presenting with difficulty breathing, cyanosis, drowsiness, lethargy, or complications like shock, heart failure, respiratory failure, and acute respiratory distress syndrome.
3. Chest signs may be minimal, but some patients exhibit rapid breathing, increased heart rate, cyanosis, or dry/moist rales.

How is viral pneumonia diagnosed?

Diagnosis is based on close contact history with respiratory infections, clinical symptoms, signs, and X-ray findings, while excluding pneumonia caused by other pathogens.

Definitive diagnosis relies on pathogen testing, including viral isolation, serology, and viral antigen detection.

How is viral pneumonia treated?

1. General treatment:

① Bed rest, adequate vitamins and protein, plenty of fluids, and small frequent meals. Intravenous fluids may be given to maintain electrolyte balance.

② Regular ventilation, isolation, and disinfection to prevent cross-infection.

③ Oxygen therapy if needed, maintaining normal oxygen levels, and clearing respiratory secretions to ensure airway patency.

2. Medications:

① Antiviral drugs:

• Ribavirin: Broad-spectrum antiviral for influenza, respiratory syncytial virus, adenovirus, etc.
• Acyclovir: Potent and fast-acting for herpesvirus and varicella-zoster virus; early use recommended for immunocompromised patients.
• Ganciclovir: Inhibits viral DNA synthesis for cytomegalovirus infections.
• Oseltamivir: Low resistance, effective against influenza A and B.
• Vidarabine: Broad-spectrum, used for herpesvirus and varicella in immunocompromised patients.
• Amantadine: Blocks viral entry and reduces fever for influenza.

② Corticosteroids:

• Controversial efficacy; may increase mortality, prolong mechanical ventilation/hospital stay, and raise secondary infection risk. Not routinely recommended.

③ Others:

• Antipyretics for fever; expectorants (e.g., ambroxol, acetylcysteine) for thick sputum.
• Bronchodilators (e.g., terbutaline, ipratropium) for wheezing.
• Antibiotics/antifungals for secondary bacterial/fungal infections.

What is the prognosis for viral pneumonia?

Most patients recover within 1–3 weeks with a good prognosis.

Severe cases (often immunocompromised, young, or elderly) may require hospitalization, but most recover fully.

Patients with severe underlying conditions may have irreversible lung damage, multi-organ failure, or death.

How to prevent viral pneumonia?

1. Isolate infected patients until recovery.
2. High-risk individuals should wear masks and avoid crowded places during outbreaks.
3. Vaccinate against influenza, measles, and varicella.
4. Exercise regularly and maintain a balanced diet to boost immunity.