Musculoskeletal - Clubbing and Other Hand/Nail Findings
LSU Physician Champion - Dr. John Amoss
Early clubbing of the nails causes a straightening of the normal nailbed angle of around 160 degrees to 180 degrees or greater.
Two commonly used signs of clubbing are the schamroth sign and a phalangeal depth ratio of greater than 1. The schamroth sign is the absence of a closed triangular space when the two the distal phalanges of the index fingers are held in dorsal opposition. The phalangeal depth ratio is the ratio of the distal phalangeal depth over the interphalangeal depth. Ratios greater than 1 are found in clubbing.
As clubbing progresses, the nailbed angle increases and the nailbed becomes spongy
Common causes of clubbing are lung cancer, chronic lung infections, brochiectasis, cystic fibrosis, interstitial pulmonary fibrosis, endocarditis, cyanotic congenital heart disease and inlamatory bowel disease. Importantly, COPD does not cause clubbing. Patients with COPD and clubbing should be evaluated for an underlying cause particularly lung cancer.
Curved nails, which have no clinical significance, are commonly misdiagnosed as clubbing. Patients with curved nails maintain the normal nailbed angle of approximately 160 degrees.
Splinter hemorrhages are common and usually related to trauma. They represent ruptured nailbed capillaries and most frequently involve the distal nailbed. They are non-specific but can be seen in endocarditis.
Osler Nodes and Janeway Lesions
Osler nodes and Janeway lesions are relatively uncommon lesions seen in endocarditis. Osler nodes are microthrombi that cause tender nodules commonly seen on the pads of the fingers and toes. Janeway lesions are microabscesses that cause nontender macules on the palms and soles.
Heberden’s nodes are painless bony overgrowths in the distal interphalangeal joints seen in osteoarthritis. Bouchard’s nodes are less common but are similar bony overgrowths in the proximal interphalangeal joints.
Acute rheumatoid arthritis commoly causes a symetrical arthritis of the proximal interphalangeal joints and the metacarpal phalangeal joints. The distal interphalangeal joints are usually spared.