Pulp Space Infections
Matthew B. Cantlon
Definition—Infection contained in the closed and unyielding septal spaces of the distal volar pad of the finger or thumb. Also referred to as a “felon.”
Epidemiology—Represents up to 20% of all hand infections1 and 6% of all incision and drainage procedures performed on the hand.2
Mechanism of injury
Vast majority of injuries arise from prior lacerations or penetrating trauma such as wooden or metal splinters or glass (Figure 42.1). Injuries can occur in diabetics from repeated glucose finger-stick testing.
Eccrine sweat glands may become colonized with bacteria that occasionally lead to a pulp space infection.
Local inoculation from underlying osteomyelitis may also occur.
Staphylococcus aureus is the most common (75% of all hand infections). Methicillin-resistant S. aureus (MRSA) is now more common than methicillin-susceptible S. aureus in most urban centers.2 Risk factors for MRSA include immunocompromised status, HIV infection, diabetes, intravenous drug use, and being a health care worker.3,4
Polymicrobial infection is the next most common, followed by Streptococcal species.2
Gram-negative species may occur in diabetics and immunocompromised individuals.
Glabrous skin of the volar fingertip is tethered to the periosteum of the distal phalanx and to the flexor sheath more proximally in the finger via vertical fibrous septa. Adipose tissue and eccrine sweat glands occupy the closed spaces created by these septae5 (Figure 42.2).
Cellulitis or local swelling leads to vascular congestion and swelling within the rigid and unyielding septae, which produces pressure necrosis, acting as a mini “compartment syndrome” of the pulp, usually within 24 to 48 hours of symptom onset.6
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