Pulmonary clubbing

Specialty: Respiratory.

• club fingers
• digital hypocratism
• Pneumological hypertrophic osteoarthropathy

Why it occurs

• Idiopathic pulmonary fibrosis (IPF) (chronic tissue hypoxia and peripheral release of growth factors such as PDGF and VEGF by megakaryocytes that bypass the pulmonary filter induce nail bed hypertrophy)
• Non-small cell lung cancer (especially lung adenocarcinoma, where clubbing can develop rapidly as part of the paraneoplastic syndrome)
• Chronic diffuse bronchiectasis or cystic fibrosis (infection and chronic suppurative inflammation of the airway with sustained hypoxemia)
• Unresolved or poorly drained chronic pleural empyema (persistent pleural inflammation)
• Cyanogenous congenital heart disease with right-left shunt (extrapulmonary cause of clubbing associated with chronic hypoxia).

Initial workup

Chest x-ray in two projections; High-resolution chest computed tomography (CT) (search for neoplasia or usual interstitial pneumonia pattern - UIP); Measurement of the Lovibond angle (angle greater than 180° between the base of the nail and the finger); X-ray of long bones of extremities (search for symmetrical periosteal reaction); Forced spirometry and diffusing capacity for carbon monoxide (DLCO).

Standard management

• Management is exclusively of the underlying lung pathology
• Nintedanib — antifibrotic, tyrosine kinase inhibitor, 150 mg orally every 12 hours in case of Idiopathic Pulmonary Fibrosis
• Pirfenidone — antifibrotic, 267 mg three times a day with progressive escalation to 801 mg three times a day in IPF
• Naproxen (250-500 mg orally every 12 hours if associated with joint pain due to hypertrophic osteoarthropathy).