Definition: Clubbing is a thickening and broadening of the bulbous fleshy portion of the fingers under the nails. The nail becomes curved both longitudinally and laterally. As the underlying condition progresses the curvature becomes more prominent. Curvature of the nail alone may not be significant to diagnose clubbing and should be backed up by the softening of the nailbed. Therefore apparent clubbing may have no significance in a healthy individual.
Test procedure: 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.
Test findings: Finger / nail clubbing can be caused by: Diseases of the lungs: Bronchiectasis, (ie from cystic fibrosis), Abscess or Empyema, Bronchogenic cancinoma, Pneumoconiosis, Pulmonary sepsis, Chronic infections, Fibrosing alveolitis. Diseases of the heart: Bacterial endocarditis, Cyanotic congenital heart disease. Abdominal pathologies: Cirrhosis of the liver, Inflammatory bowel disease e.g. Crohn?s disease, In non pathological cases finger clubbing (of congenital origin) does not signify pathology. Also note that on careful examination the nail and nailbed will not behave as with pathological cases.