Idiopathic interstitial pneumonias

• Rare
• Reaction to lung injury
• Variable inflammation and fibrosis
• Variable response to treatment

Common disorders such as sarcoidosis, vasculitis and connective tissue disorders display an identicle morphologic pattern. Bleomycin drug toxicity can also give a similar appearance.

Idiopathic pulmonary fibrosis (IPF)

• Usual interstital pneumonia (UIP) is the histologic pattern
• Basal and peripheral reticular opacities
• Honeycombing, subpleural cysts
• Traction bronchiectasis due to surrounding fibrosis
• Apicobasal gradient - gets worse from apex to base
• Limited ground glass opacities
• Heterogeneous - diseased lung alternating with healthy lung
• Exclusion of known causes (toxins, environmental exposure, collagen vascular disease, etc)
• Reduced lung volume on x-ray
• Mean survival 3 years

Nonspecific intersitial pneumonia (NSIP)

• Basal ground glass opacitis predominate over reticulat opacities
• Rare minimal honeycombing
• Subpleural sparing
• Potentially reversible with immunosupression
• Homogeneous
• Can be cellular (GGO) and/or fibrotic (traction bronchiectasis"
• Much better prognosis than UIP, esecially cellular NSIP

Cryptogenic organizing pneumonia (COP)

• Patchy peripheral subpleural or peribronchovascular consolidation
• Atoll sign, aka reverse halo
• Idiopathic inflammation of the bronchioles and surrounding tissue causing granulation tissue and "non-infectious pneumonia"
• Responds to steroids not antibiotics
• a/w many systemic diseases (lupus, c-anca, GVHD, etc)
• No pleural effusion or lymphadenopathy
• aka BOOP
• Usually present after treatment with antibiotics and persistent fever and opacities
• Looks just like Eosinophillic pneumonia

Respiratory Bronchiolitis associated Interstitial Lung Disease (RB ILD)

• Smoking related disease
• Centrilobular nodules
• Ground glass opacities
• Upper lobe predominant

Desquamative Intersitial Pneumonia (DIP)

• Smoking related disease
• Centrilobular nodules
• Ground glass opacities
• Lower lobe predominant

Lymphoid Intersitial Pneumonia (LIP)

• Groung glass opacities
• Cystic lesions, generallt fewer in number (10-20)
• Can be a/w sjogren.

Acute Interstial Pneumonia (AIP)

• Diffuse lung consolidation
• Groung glass opacities
• Progress to fibrosis after acute phase

Links

Radiology Assistant webpage