Fast Five Quiz: Idiopathic Pulmonary Fibrosis Differential Diagnosis

Guy W. Soo Hoo, MD, MPH


November 20, 2019

Common lung diseases included in the differential diagnosis of IPF are nonspecific interstitial pneumonitis (NSIP), chronic hypersensitivity pneumonia (CHP), and fibrotic sarcoidosis (also referred to as stage 4 sarcoidosis [S4]).

IPF and NSIP are both idiopathic interstitial pneumonias that have similar presentations. Although CHP and S4 are not fibrotic diseases and have known etiologies, they can mimic signs and symptoms of IPF, and in late stages of disease, they demonstrate similar findings on high-resolution CT (HRCT) studies.

Although NSIP and IPF share a similar clinical presentation, NSIP is more common in women in the fifth and sixth decades of life and in male and female nonsmokers, whereas IPF is more common in men older than 60 years who have a history of smoking. Regarding presenting signs and symptoms, although both patients with NSIP and IPF typically report gradual worsening dyspnea over the course of several months, patients with NSIP may also present with autoimmune features (eg, arthralgias, skin changes, esophageal changes).

Although NSIP, CHP, and S4 can mimic IPF, their prognosis, management, and treatment differ. For this reason, differentiation of IFP from NSIP, CHP, and S4 is imperative. For example, patients with IPF are treated with antifibrotic medications; NSIP and S4, which have favorable prognoses, are treated with anti-inflammatory medications; and CHP is treated by removing the causative antigen.

When considering other fibrotic-like diseases that share similar presenting signs and symptoms as IPF, bronchitis, pertussis, cystic fibrosis, lung cancer, and tuberculosis are not included in the differential diagnosis. Likewise, PE, pneumonia, and bronchiectasis are also not included in the differential diagnosis for IPF, as their presenting symptoms and patient history differ from those of IPF.

As with any patient workup, a detailed personal, social, and occupational history-taking is crucial to ensure accurate diagnosis and initiate appropriate treatment.

For more on the differential diagnosis of IPF, read here.


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