Pneumonia, Acute Interstitial

Key Features

• Known clinically as Hamman-Rich syndrome

Clinical Findings

• Wide age range, including many young patients

• Acute onset of dyspnea followed by rapid development of respiratory failure

• Preceding viral syndrome is reported by 50% of patients

• Clinical course is indistinguishable from idiopathic acute respiratory distress syndrome (ARDS)

Diagnosis

• Radiograph shows diffuse bilateral airspace consolidation

• High-resolution CT scan shows areas of ground-glass attenuation

• Biopsy resembles the organizing phase of diffuse alveolar damage, with fibrosis and minimal collagen deposition

• Pathologically similar to usual interstitial pneumonia but more homogeneous, and honeycombing is typically absent

Treatment

• Supportive care including mechanical ventilation is critical

• Nintedanib and pirfenidone reduce rate of decline in lung function

• 50–90% of patients die within 2 months

• Course is not progressive if patient survives

• Lung function may be permanently impaired in survivors