Definition: A selective bulbous enlargement of the distal segment of digit due to an increase in soft tissue. Pseudoclubbing is Increase in longitudinal curvature of the nail with loss of nail plate material and is seen scleroderma, thyroid carcinoma , and sarcoidosis. X ray of fingers show resorption of terminal tufts (acro-osteolysis) instead of an overgrowth of phalangeal tufts seen in clubbing. Finger involvement is asymmetrical as compared to clubbing. MECHANISMS: Humoral theory states that an unidentified humoral substance causes dilatation of vessels of the finger tip.
Persistant hypoxia causes opening up of the deep arteriovenous fistulae of fingers . Reduced ferritin in the blood level causes dilatation of the arteriovenous anastomoses and hypertrophy of the terminal phalanx . Vagal theory states that persistent Vagal stimulation causes vasodilation and clubbing. Recent…
