Hand & Wrist Emergencies & Closed-Space Infections

Infectious tenosynovitis of the flexor tendon sheath rapidly destroys the gliding mechanism, causing tendon necrosis and permanent hand dysfunction:

High-pressure paint, grease, solvent, or hydraulic fluid guns operating at 2000-10,000 PSI cause insidious, limb-threatening injuries:

• Misleading Presentation: Typically looks like a tiny, benign 1-2 mm puncture on the non-dominant index fingertip with minimal initial pain.
• Pathophysiology: Fluid shoots along fascial planes and neurovascular bundles down the entire digit into the palm and forearm, causing chemical solvent necrosis, vascular thrombosis, and compartment syndrome.
• Amputation Risk: Up to 50-80% of industrial paint/solvent injection injuries require amputation if surgical debridement is delayed.
• Management: (1) IMMEDIATE emergent hand surgery consultation; (2) Keep patient strictly NPO for OR; (3) Update tetanus; (4) IV broad-spectrum antibiotics (Ampicillin-sulbactam); (5) DO NOT inject local digital blocks with epinephrine (worsens digital ischemia).

• Paronychia: Infection of the lateral nail fold. Early cellulitis -> Warm soaks + oral cephalexin. Fluctuance -> Lift eponychial fold with an 18G needle or #11 scalpel blade (no incision needed).
• Felon: Infection of the pulp space of the distal phalanx. Fibrous vertical septa create high-pressure compartments risking osteomyelitis and digital artery thrombosis. Incise longitudinally along the non-working side (lateral radial aspect for fingers, ulnar for thumb/little finger) or volar midline directly over maximal fluctuance.
• Thenar Space Abscess: Ballooning of the first web space, thumb held in abducted/extended position. Requires urgent surgical drainage.
• Midpalmar Space Abscess: Loss of normal palmar concavity, tenderness over midpalm, pain on flexing middle and ring fingers.

• Mechanism: Fall on an outstretched hand (FOOSH) with wrist in extension and radial deviation.
• Three Physical Exam Maneuvers: (1) Anatomic snuffbox tenderness (dorsal); (2) Scaphoid tubercle tenderness (volar proximal wrist crease); (3) Pain with axial loading of the thumb.
• Occult Fracture Rate: 15-20% of scaphoid fractures are radiographically invisible on initial plain X-rays.
• Blood Supply & Avascular Necrosis (AVN): Blood enters distally via branches of the radial artery and flows retrograde to the proximal pole. Proximal pole fractures carry a 30-50% risk of avascular necrosis and nonunion if not immobilized.
• Management: Any patient with clinical scaphoid tenderness must be immobilized in a Thumb Spica Splint and scheduled for repeat imaging (MRI or CT) in 10-14 days regardless of normal initial X-rays.