Digital clubbing: a unique case and a new hypothesis.

A study of a unique case of unilateral digital clubbing secondary to a true posttmaumatic aneurysm of the ulnar artery in the palm is presented. The clubbing of the digits resolved following resection of the aneurysm. Detailed evaluation of the patient included Doppler flow studies, differential pulse pressure recordings, measurement of reactive hyperemia, angiography, and differential capillary blood gas determinations. The contralateral hand of this otherwise healthy young patient was employed as a control. Findings of increased blood flow, decreased peripheral resistance, and increased oxygenation then were evaluated in light of the findings of other investigators. This study and the information gathered from an extensive review of the literature strongly suggest that a neurocirculatory reflex is the common denominator of the various conditions associated with clubbing. The afferent and efferent limbs of this reflex are proposed.