II. Epidemiology
- Accounts for 1 in 600 hand injuries
- Most common in young male laborers working with paint, automotive grease, solvents, diesel oil
III. Background
- Associated with occupational paint or spray gun use
- Nozzle pressures are very high (up to 10,000 psi, much higher than rated psi)
- Injection substances are delivered at speeds approaching 400 mph
- By comparison, even forces as low as 100 psi are strong enough to break through skin
- Injected materials typically spread broadly
- Spread along planes of least resistance
- Neurovascular bundles
- Tendon sheaths
- Hand compartments
- Results in direct injury, local ischemia, chemical inflammation and Granulomatous reaction
- Risk of vascular necrosis and local soft tissue necrosis
- Also sets the stage for secondary infection
- Spread along planes of least resistance
IV. Risk Factors: Amputation
- High pressure >1000 psi (43% versus 19% with low pressure injections)
- Delay to operating room >6 hours (58% versus 38% with earlier surgery)
- Injected solvents are at highest risk of amputation (50%)
- Organic solvents (paint thinner, paint and oil-based products, diesel fuel, jet fuel, oil)
- Water or air injections are not associated with amputations
- References
V. History
- Time of injury
- Delayed presentation is common (mean 9 hours after injury)
- Delays (esp. >6 to 10 hours) are associated with high amputation and infection rates
- Injected substance
- Clean water and air are considered lower risk injection injuries
- Paint is associated with large inflammatory responses and high amputation rates
- Grease is associated with less inflammatory response and lower amputation rates
VI. Symptoms
- Non-dominant index finger most commonly affected
- Initial injury appears relatively mild
- Patient develops numbness, burning or pain over time
VII. Signs
- Deceptively small entry wound despite severe subcutaneous damage
- With toxic injections, injury site becomes pale, edematous and very tender to palpation
VIII. Labs: Agent injected has risk of hepatotoxicity and nephrotoxicity
IX. Imaging
- XRay
- May demonstrate radiopaque substance
- Subcutaneous Emphysema may be present
X. Management
- Immediate surgical Consultation (e.g. hand surgery)
- Emergent surgical intervention is per surgeon's discretion
- Most injection injuries require surgical management (>50%)
- Early surgical decompression and Debridement of caustic injections
- Injection injuries (water and air only) without Compartment Syndrome may not require surgery
- Poison control Consultation (if indicated by substance injected)
- High risk injury!
-
General measures
- Tetanus Prophylaxis
- Elevate the affected extremity
- Splint and immobilize the affected limb
- Broad-spectrum empiric antibiotics
- Parenteral antibiotics
- Leave wounds open
- Avoid measures that results in decreased perfusion (excessive swelling and vasospasm)
- Avoid Digital Blocks
- Avoid local ice
XI. Complications
- Limb Amputation (approaches 30%)
- Pyogenic Flexor Tensynovitis
- Staphylococcus aureus is most common
- Other rare delayed complications
- Oleogranuloma
- Fibrohistiocytic tumor
- Squamous Cell Carcinoma
XII. Course
- Precaution
- Most high pressure washers provide >2000 psi at the nozzle (which may be >10x higher than rated psi)
- Amputation Incidence
- Amputation rate: 50% if injection psi >2000
- Amputation rate: <40% if injection psi <2000
XIII. References
- Hori (2015) Crit Dec Emerg Med 29(3): 2-7
- Kiel (2023) Crit Dec Emerg Med 37(11): 18-9
- Hogan (2006) J Orthop Trauma 20(7): 503-11 [PubMed]
- Vasilevski (2000) Am J Emerg Med 18:820-4 [PubMed]