Definition: Also referred to as: Hippocratic fingers and Digital Clubbing.
Clubbing is the pathological thickening and broadening of the soft tissue surrounding the terminal phalanx under the nails. The nails also become curved both longitudinally and laterally. Clubbing is present if there is: Increased nail bed fluctuance, loss of normal nail bed/nail angle (loss of Lovibond angle).
Clubbing shows the following progression:
- Fluctuation and softening of the nail bed.
- Loss of the normal angle between the nailbed and the nailfold.
- Increased convexity of the nail.
- Thickening of the whole distal phalanx.
- And striation of the nail and surrounding skin.
Causes: There are many causes of finger clubbing. Systemic causes are most often cardiothoracic (including abscess, asbestosis, bronchiectasis, bacterial endocarditis, carcinoma, cystic fibrosis, empyema, fibrosing alveolitis and cyanotic congenital heart disease) or less commonly gastroenterological (including cirrhosis, ulcerative colitis, Crohn’s and gluten enteropathy). Clubbing can also be hereditary / idiopathic. Development of clubbing in systemic disease is generally gradual and reversible once cause removed.
Examination: Observe both hands carefully (NB. clubbing can also be seen on toes). Clubbing is usually bilateral and non-tender. Finger tips appear swollen and there is increased nail curvature in later stages. Examine nail and nail bed by asking patient to align fingers as in picture. In clubbing the normally obtuse nail bed angle is obliterated. Now with the two nails back to back against a light, try to observe a diamond-shape formed by the two nailbed angles (known as Schamroth’s window). In clubbing this is obliterated.
Assess for nail bed fluctuance or sponginess by gently but firmly trying to move nail on nail bed. It is best assessed in the early stages when the nail bed becomes softer and can be rocked from side to side.Test all nails on both hands.
Curvature of the nail alone may not be significant enough to diagnose clubbing and should be supported by evidence of a soft, unstable nail bed. Therefore apparent clubbing may have no significance in a healthy individual such those with familial or racial variations. However, when clubbing is observed you should consider primarily long term pathologies principally of the lungs, abdomen and heart.
In more detail finger clubbing may be caused by:
Diseases of the Lungs:
- Lung cancer especially bronchogenic carcinoma
- Interstitial lung disease
- Abscess or Empyema
- Pulmonary sepsis
- Chronic infections esp. Tuberculosis, and
- Fibrosing alveolitis
Diseases of the Heart:
- Subacute bacterial endocarditis
- Cyanotic congenital heart disease, and
- Chronic hypoxia
- Cirrhosis of the liver.
- Inflammatory bowel disease such as Crohn’s and ulcerative colitis.
- Oesophageal cancer.
- Other conditions inc. hyperthyroidism and thymoma.