Chapter 51. Clubbing

A 31-year-old man with congenital heart disease has had these clubbed fingers since his childhood (Figures 51-1 and 51-2). A close view of the fingers shows a widened club-like distal phalanx. He has learned to live with the limitations from his congenital heart disease and his fingers do not bother him at all.

Clubbing is a physical examination finding first described by Hippocrates in 400 bc. Clubbing can be primary (pachydermoperiostosis or hypertrophic osteoarthropathy) or secondary (pulmonary, cardiac, or GI disease or HIV). Diagnosis is clinical based on nail fold angles and phalangeal depth ratios. The treatment is to correct the underlying cause, after which clubbing may resolve.

Hippocratic nails or fingers, drumstick fingers.

Prevalence in the general population is unknown:

• Two percent of adult patients admitted to a Welsh general medicine or surgery service.1
• Thirty-eight percent and 15% of patients with Crohn disease and ulcerative colitis, respectively.2
• Thirty-three percent and 11% of patients with lung cancer and chronic obstructive pulmonary disease (COPD), respectively.3

• The etiology of clubbing is poorly understood.
• Increased connective tissue growth and angiogenesis in the nail bed result in the remodeling of the finger into a club shape.
• Current explanations include megakaryocyte release of platelet-activated growth factor, hypoxia, vasodilators in circulation, a neurocirculatory mechanism, and chronic activation of macrophages with production of profibrotic factors.4

• Family history.
• History of a disease associated with clubbing.

Clinical Features

• History of present illness: Gradual onset of painless enlargement at the ends of the fingers and toes.
  • Family history suggests primary hypertrophic osteoarthropathy/familial clubbing.
  • Social history to identify exposure to asbestos, coal mine dust, and pigeons; tobacco use as risk factor for lung cancer; HIV and tuberculosis risk factors.
• Review of systems: Constitutional, pulmonary, GI, and musculo­skeletal symptoms for clues to an underlying disease.5

Physical Examination

• Abnormal nail fold angles6 (Figure 51-3).
  • Profile angle (ABC) ≥180 degrees.
  • Hyponychial (ABD) ≥192 degrees.
  • Phalangeal depth ratio (BE:GF) ≥16 (Figure 51-3).
• Schamroth sign, obliteration of the diamond shape normally created when dorsal surfaces of 2 corresponding fingers are opposed (Figure 51-4). LR+ (likelihood ratio) 7.60 to 8.40 and LR− 0.14 to 0.25.7

Typical Distribution

• Bilateral; involves all fingers and often toes.
• Rarely unilateral or involving only one or some digits (consider neurologic or traumatic insult to extremity).

Laboratory Testing

Laboratory testing is useful to evaluate for secondary causes. Consider:

• HIV testing if risk factors present.
• Complete blood count (CBC) and blood cultures if systemic symptoms (fever, night sweats, weight loss) are present.
• Thyroid-stimulating hormone (TSH)/thyroxine (T4) if exophthalmos or pretibial myxedema is present.
• Liver function tests (LFTs), hepatitis serologies for right upper quadrant (RUQ) tenderness or jaundice.

Imaging

• Screening chest radiograph if an underlying cause is not identified.
• Plain radiograph of the hand can distinguish clubbed from nonclubbed by measuring nail bed greater than or equal to to 3 mm.8

Primary Clubbing

• Hypertrophic osteoarthropathy (HOA)—Clubbing, periostosis, and arthritis or arthralgias.
  • Primary HOA, also known as pachydermoperiostosis, is an autosomal dominant disorder.
  • Secondary HOA is often associated with pulmonary neoplasms.
• Familial clubbing, now thought to be an incomplete form of primary HOA.

Secondary Clubbing

Secondary clubbing can be caused by many conditions, including:5

• Pulmonary—Idiopathic pulmonary fibrosis, malignancy, asbestosis, COPD, and cystic fibrosis.
• Cardiac—Congenital heart disease, endocarditis, atrioventricular malformations, or fistulas.
• GI—Inflammatory bowel disease, cirrhosis, and celiac disease.
• HIV infection—Clubbing was found in 36% of patients with HIV in one study.9

• Clubbing improves with the management of the underlying disease.2
• Evaluate patients without an obvious associated disease for lung cancer.5 SOR C
• Evaluate patients with COPD and a phalangeal depth ratio greater than 1 for lung cancer.3 (LR 3.9) SOR B

Prognosis depends on the underlying process. Clubbing usually completely reverses after successful treatment of the underlying process.

Follow-up is dependent on the underlying disease process.

Clubbing may be secondary to many different types of disease, some very serious.

Patient Resources

• Medline Plus—http://www.nlm.nih.gov/medlineplus/ency/article/003282.htm.

Provider Resources

• Spicknall, et al.5 provide an algorithm useful in identifying the underlying cause of clubbing.