In addition to COPD, clubbing may be seen in which condition?

• A. Hyperlipidemia
• B. Asthma
• C. Liver disease
• D. Renal failure

Answer: (C)

Clubbing of the fingers occurs with diseases that cause long-standing hypoxia or systemic factors that promote tissue growth at the nail beds. Besides COPD, liver disease is a classic nonpulmonary condition that can be associated with clubbing. The idea is that liver dysfunction can allow circulating megakaryocytes to bypass the lung’s filtering and release growth factors (like PDGF and VEGF) at the nail bed, stimulating tissue proliferation and giving the nails a rounded, bulbous appearance. Hypoxemia from hepatopulmonary syndrome can also contribute, but the key concept is that systemic factors related to liver disease can produce clubbing. The other options—hyperlipidemia, asthma, and renal failure—do not typically cause clubbing.