There are various causes of clubbing. Clubbing was first described by Hippocrates. It is deformity of the nails mostly associated with cardiac and pulmonary conditions. Its basically the exaggeration of the normal nail curvature associated with the loss of normal angle between the nail and the posterior nail fold.
The sign demonstrated is known as the Schamroth Sign which is associated with clubbing. In this sign the normal diamond shaped window formed between opposing dorsal surfaces of the fingers is not present in clubbed fingers.
- Unilateral clubbing occurs in pancoast tumor or aneurysms of subclavian, aorta and innominate artery.
- Unidigital clubbing in which only a single digit is clubbed is related to digital mucoid cyst, osteomas, myxchondroma, trauma, gout and sarcoidosis.
Selective lower Limb clubbing also known as differential clubbing occurs in patients with patent ductus arteriosus associated with pulmonary hypertension and right to left shunt.
Differential clubbing is also associated with infected abdominal aortic aneurysm.
COPD and tuberculosis are not associated with clubbing.
If clubbing is present in association with these conditions (namely COPD and Tuberculosis) then underlying malignancy and bronchiectasis must be looked for.
- Endocrine causes include myxedema, thyroid acropachy/ hyperthyroidism and acromegaly
- Clubbing may also be idiopathic or hereditary
- Chronic Bronchitis is not a cause of clubbing.