Club

Clubbing

Clubbing refers to the bulbous enlargement of the ends of one or more fingers or toes. It is a physical sign that can be associated with a variety of underlying medical conditions, particularly those affecting the heart and lungs.

History

The phenomenon of clubbing was first described by Hippocrates, the ancient Greek physician, and is sometimes referred to as "Hippocratic fingers." It has been recognized as a clinical sign for centuries and is often associated with chronic hypoxia.

Pathophysiology

The exact mechanism of clubbing is not fully understood, but it is believed to involve increased blood flow to the distal phalanges and changes in connective tissue. The following factors are thought to contribute:

• Increased vascular endothelial growth factor (VEGF)
• Platelet-derived growth factor (PDGF)
• Changes in the levels of prostaglandins

Causes

Clubbing can be associated with a variety of conditions, including:

Pulmonary Causes

• Lung cancer
• Cystic fibrosis
• Interstitial lung disease
• Bronchiectasis
• Pulmonary fibrosis

Cardiac Causes

• Cyanotic congenital heart disease
• Infective endocarditis

Gastrointestinal Causes

• Inflammatory bowel disease
• Cirrhosis
• Celiac disease

Other Causes

• Thyroid acropachy
• Primary hypertrophic osteoarthropathy

Clinical Features

Clubbing is characterized by:

• Softening of the nail bed
• Increased convexity of the nail
• Thickening of the distal finger (drumstick appearance)
• Loss of the normal angle between the nail and the nail bed

Diagnosis

Diagnosis of clubbing is primarily clinical. The following methods can be used to assess clubbing:

• Schamroth's window test: Absence of a diamond-shaped window when the dorsal surfaces of the distal phalanges of corresponding fingers are opposed.
• Profile sign: Increased angle between the nail and the nail bed when viewed from the side.

Management

Management of clubbing involves addressing the underlying cause. There is no specific treatment for clubbing itself. Identifying and treating the underlying condition can sometimes lead to improvement in clubbing.

See Also

• Nail diseases
• Digital clubbing

References

• Schamroth, L. (1976). "Personal experience. Finger clubbing as a diagnostic sign." South African Medical Journal, 50(8), 297-300.
• Spicknall, K. E., Zirwas, M. J., & English, J. C. (2005). "Nail dystrophies: pathogenesis and management." American Journal of Clinical Dermatology, 6(1), 1-16.