Clubbing

Bulbous enlargement at the ends of fingers and toes. There is increased nail convexity causing a loss of angle between the nail and nail bed. It may be revealed by loss of Schamroth's window.

Mechanism

Highly debated

• Tissue Hypoxia
• Circulating Vasodilator
• Neurocirculatory Reflex

Shneerson JM. Digital clubbing and hypertrophic osteoarthropathy: the underlying mechanisms. Br J Dis Chest. 1981;75:113–31.

Causes

Chronic Hypoxia

• Lung Cancer
• Interstitial lung disease: Sarcoidosis, Asbestosis
• Cystic Fibrosis
• Congenital Heart Disease

Malabsorption

• Celiac Disease
• Inflammatory Bowel Disease: Crohn's, Ulcerative Colitis
• Liver Cirrhosis

Other

• Grave's Disease