A 40-year-old man with subacute bacterial endocarditis has tender, erythematous nodules on the pads of his fingers and painless macules on his palms. The finger-pad nodules differ from the palmar lesions because they are caused by:

• A Septic microemboli
• B Immune complex deposition ✓
• C Direct bacterial invasion of the dermis
• D Cholesterol crystal embolisation

Explanation

Osler nodes, the painful lesions on finger and toe pads, result from immune complex deposition with localised vasculitis, whereas Janeway lesions, the painless macules on palms and soles, are caused by septic microemboli. Both are minor Duke criteria. Cholesterol embolisation produces livedo reticularis and blue toes in atherosclerotic disease, not these classic endocarditis stigmata, and direct dermal invasion is not the recognised mechanism for either lesion.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

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Written and medically reviewed by the StethoPrep medical team.