Clubbing

Common causes of Clubbing:

• Gastrointestinal: liver disease, inflammatory bowel diseases, celiac disease, malignancy
• Pulmonary: malignancy, suppurative (empyema, abscess), Cystic Fibrosis, TB, bronchiectasis, many fibrosing conditions (like IPF), AVM's
• Cardiac: endocarditis, cyanotic heart diseases
• Other: hyperthyroidism, alpha 1 antitrypsin, sarcoid, lymphoma

Physical Examination for clubbing:

• Look for changes in the nail shape, like increased PA and lateral diameter, and a "bird-beaking" or "drumstick" appearance to the nail.
• Palpate a spongy texture to the nailbed.
• "Phalangeal Depth Ratio": See the picture below in Frame C. Normally the finger height at the DIP should be greater than at the distal phalanx. In clubbing, the height at the distal phalanx is greater than the at the DIP.
• Angles: See the picture below in Frame B: the Profile angle (also known as Lovibonds angle) is increased greater than 180 degrees in clubbed individuals - this is angle ABC below; and the Hyponychial angle is greater than 190 degrees in clubbing as well - this is angle ABD below.
• Shamroth Sign: See the picture below. This is an indirect measurement of the Profile angle (aka Lovibonds angle). When you put two fingers together at the terminal phalanx, you should see a diamond shape. This is lost in clubbed individuals.

What is the evidence for all this?

• JAMA has a good article in their Rational Clinical Exam Series at this link.
• There is a recent paper specific to the utility of Shamroth's sign in JAMA here as well.
• Bottom line: the Phalangeal Depth Ratio and Shamroth Sign are the more useful findings.

(Image is from the JAMA Rational Clinical Exam series; 2001, 286, 341-47 at this link)