Viral Pneumonia Requiring Differentiation from Acute and Progressive Diffuse Interstitial Lung Diseases

Area of Science:

• Pulmonology
• Infectious Diseases
• Radiology

Background:

• Clinical and imaging overlap exists between viral pneumonia and interstitial lung diseases (ILDs).
• Viral pneumonia may be underrecognized and misdiagnosed as specific ILDs.
• Acute progressive respiratory illnesses necessitate differential diagnosis between infection and ILDs.

Purpose of the Study:

• To determine the frequency of viral pneumonia in patients with acute progressive courses requiring ILD/pneumonia differentiation.
• To identify the most common ILDs misdiagnosed in cases of viral pneumonia.

Main Methods:

• Retrospective analysis of 109 hospitalized patients (2010-2017) with acute clinical courses (≤30 days).
• Bronchoalveolar lavage (BAL) performed for differential diagnosis of infection and ILDs.
• Multiplex PCR for respiratory viruses on BAL fluid; final diagnosis by multidisciplinary approach including PCR results.

Main Results:

• 53 out of 109 patients (approx. 49%) were diagnosed with viral pneumonia.
• Symptoms and laboratory data showed small differences or overlap between viral pneumonia and other diseases.
• Viral pneumonia was misdiagnosed at discharge as acute fibrinous organizing pneumonia/cryptogenic organizing pneumonia/chronic eosinophilic pneumonia (n=22), acute interstitial pneumonia (n=5), and others.

Conclusions:

• Viral pneumonia constitutes a significant proportion of acute respiratory illnesses initially suspected as ILDs.
• Acute organizing pneumonias (AOPs) were the most frequent ILD misdiagnoses for viral pneumonia.
• Viral pneumonia should be considered in the differential diagnosis of suspected ILDs, especially AOPs, due to overlapping clinical and imaging features.