Diffuse Parenchymal Lung Diseases With an Unknown Cause
Pulmonary and Critical Care Medicine · Diffuse Parenchymal Lung Disease 🎯 Practice these cards
IPF is defined by the ____ histopathologic pattern; the classic exam findings are bibasilar ____-like end-inspiratory crackles and digital clubbing in up to ____% of patients.
IPF, the most common idiopathic DPLD, is defined by the UIP histopathologic pattern; the exam classically shows bibasilar Velcro-like end-inspiratory crackles (often the earliest sign) and digital clubbing in up to 50% of patients.
The radiographic hallmark of UIP on HRCT is ____, distributed with a subpleural and ____ predominance; when the HRCT pattern is classic, lung ____ is not necessary for diagnosis.
HRCT in IPF shows bilateral reticular changes with subpleural, basal, and posterior predominance plus traction bronchiectasis and honeycombing — the radiographic hallmark of UIP. When the HRCT pattern is classic in the right clinical setting, lung biopsy is not necessary for diagnosis.
IPF carries a median survival of ____ to ____ years; nintedanib and pirfenidone slow the rate of ____ decline by roughly half but are not curative, and the only curative option is lung transplant.
IPF is progressive with a median survival of 3 to 5 years after diagnosis. Nintedanib and pirfenidone (FDA-approved 2014) slow the rate of FVC decline by roughly half but are not curative; early referral for lung transplant — the only curative option — is strongly recommended.
A landmark trial of prednisone plus ____ plus N-acetylcysteine in IPF was stopped early for increased ____ and hospitalizations; glucocorticoids have no ____ role in IPF.
Immunosuppression increases mortality in IPF: the landmark trial of prednisone plus azathioprine plus N-acetylcysteine was stopped early for increased deaths and hospitalizations. Glucocorticoids have no chronic role in IPF — unlike COP and NSIP, where they are first-line.
NSIP on HRCT shows lower-lobe reticulation with ground-glass opacities and characteristic subpleural ____; ____ is rare. NSIP has the best prognosis of the idiopathic interstitial pneumonias, with 5-year survival exceeding ____%.
Idiopathic NSIP classically affects a nonsmoking woman in her fifth decade. HRCT shows bilateral lower-lobe reticulation with scattered ground-glass opacities and characteristic subpleural sparing; honeycombing is rare. Classified as cellular (steroid-responsive, better outlook) or fibrotic (less responsive), NSIP has the best prognosis of the idiopathic interstitial pneumonias, with 5-year survival exceeding 80%.
COP classically mimics community-acquired pneumonia with patchy, often ____ consolidations that fail to respond to ____; glucocorticoids produce an excellent response, but ____ during tapering is common, so treatment continues at least 6 months.
COP presents in the 50s–60s as a subacute flu-like illness with patchy, often migratory consolidations that mimic community-acquired pneumonia but fail antibiotics (the reversed halo/atoll sign may be present). Glucocorticoids produce a brisk response, but relapse during tapering is common — treat at least 6 months and add a steroid-sparing agent for relapsing disease.
AIP is identical to ARDS — biopsy shows diffuse alveolar ____ — except that no ARDS ____ factor exists; mortality is approximately ____%, and management is supportive critical care.
AIP (historically Hamman–Rich syndrome) is clinically, radiographically, and pathologically identical to ARDS — biopsy shows diffuse alveolar damage (DAD) — except that no ARDS risk factor (sepsis, aspiration, trauma, transfusion, pancreatitis) exists. Mortality is approximately 50%, management is supportive critical care, and survivors risk chronic lung disease and relapse.
In CPFE, emphysema mechanically offsets fibrosis, so ____ and lung volumes may be preserved despite advanced disease; the signature finding is a severely reduced ____; ____ develops frequently and portends a poor prognosis.
In CPFE (seen almost exclusively in smokers), upper-lobe emphysema mechanically offsets lower-lobe fibrosis, so spirometry and lung volumes may be preserved despite advanced architectural distortion; the signature finding is a severely reduced DLCO. Pulmonary hypertension develops frequently and portends a poor prognosis; lung transplantation is the only curative therapy.
Scadding Stage ____ (hilar adenopathy alone) resolves spontaneously in more than ____% of cases, while Stage ____ (fibrosis with architectural distortion) shows no spontaneous resolution.
Scadding chest radiographic staging predicts spontaneous resolution in sarcoidosis: Stage I (hilar adenopathy with normal parenchyma) resolves spontaneously in more than 90%; Stage II (adenopathy plus parenchymal disease) ~50%; Stage III (parenchymal disease alone) ~20%; Stage IV (fibrosis with architectural distortion) shows no spontaneous resolution.
____ syndrome — bilateral hilar lymphadenopathy with erythema nodosum, migratory polyarthritis, and fever — is self-limited and needs no biopsy; ____ syndrome (uveoparotid fever) comprises anterior uveitis, ____, fever, and facial nerve palsy.
Three sarcoidosis presentations spare the biopsy: Löfgren syndrome (bilateral hilar lymphadenopathy with erythema nodosum, migratory polyarthralgia/arthritis, and fever — a favorable self-limited course), Heerfordt syndrome (anterior uveitis, parotitis, fever, and facial nerve palsy — 'uveoparotid fever'), and asymptomatic bilateral hilar lymphadenopathy.
Sarcoidosis requires biopsy showing ____ granulomas with infection excluded; when treatment is indicated, ____ are first-line, and the preferred second-line steroid-sparing agent is ____.
Sarcoidosis (lungs involved in >90% of patients) is a diagnosis of exclusion requiring biopsy showing noncaseating granulomas with mycobacterial and fungal infection excluded; a BAL CD4:CD8 ratio >3.5 supports it. Most patients need no treatment; when indicated, glucocorticoids are first-line and methotrexate is the preferred second-line steroid-sparing agent.
PPF is defined as at least ____ of three criteria — worsening symptoms, radiologic progression, or FVC/DLCO decline — within ____ year in a non-IPF ILD; the guideline conditionally recommends ____ for PPF and against antacid therapy for IPF.
The 2022 ATS/ERS/JRS/ALAT guideline defines progressive pulmonary fibrosis (PPF) as at least two of three criteria — worsening respiratory symptoms, radiologic progression, or physiologic decline (FVC or DLCO) — within 1 year in a non-IPF ILD, and conditionally recommends nintedanib for PPF. It also conditionally recommends against antacid medication and antireflux surgery as treatment for IPF.
In FIBRONEER-IPF, the oral PDE4B inhibitor ____ slowed FVC decline by ____ mL versus placebo at 52 weeks — the first positive phase 3 IPF trial in a decade — with most participants already on background ____ or pirfenidone.
The oral PDE4B-preferring inhibitor nerandomilast (18 mg twice daily) slowed FVC decline by 68.8 mL versus placebo at 52 weeks in FIBRONEER-IPF — the first positive phase 3 IPF trial in a decade — notably with 77.7% of participants already taking background nintedanib or pirfenidone.
In the TETON trials, inhaled ____ reduced FVC decline by approximately ____ mL at 52 weeks in IPF; the earlier INCREASE trial led to the first FDA-approved therapy for ____ in 2021.
In the 2026 TETON-1/2 program, inhaled treprostinil reduced FVC decline by approximately 130 mL at 52 weeks in IPF regardless of pulmonary hypertension status. The earlier INCREASE trial (improved 6-minute walk, reduced clinical worsening) produced the first FDA-approved therapy for PH-ILD in 2021 — whereas riociguat is contraindicated in group 3 PH.
The 2025 ERS/ATS classification renames AIP to idiopathic diffuse alveolar ____ (iDAD), renames DIP to alveolar ____ pneumonia (AMP), and introduces ____ interstitial pneumonia (BIP).
The 2025 ERS/ATS international multidisciplinary classification replaces acute interstitial pneumonia (AIP) with idiopathic diffuse alveolar damage (iDAD), renames desquamative interstitial pneumonia (DIP) as alveolar macrophage pneumonia (AMP), and introduces bronchiolocentric interstitial pneumonia (BIP) as a major pattern — the disease entities are unchanged, only the terminology.
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