High-Pressure Injection Injury

​HPI:
Otherwise healthy middle-aged male presents to ED with L hand pain.  He is a painter, and while cleaning a high-pressure pneumatic pain gun it accidentally discharged into the palm of his L hand.  He reports only moderate pain at the site.  Denies any other injuries, all vital signs within normal limits.  Event occurred 2 hours prior to ED arrival.

Exam:
Pin-hole size puncture wound on palmar surface of hand w/ moderate tenderness to palpation and minimal surrounding erythema.  Full passive/active ROM of all digits, neuromuscular function completely intact.  Cap refill <2 seconds in all 5 digits.  X-ray is unremarkable.

​Discussion:
High-Pressure Injection Injuries occur when a high-pressure injection device (pneumatic paint gun, grease gun, diesel injector, etc) injects into the operator.  Most common in male laborers in painting and automotive industries, and injury often occurs during cleaning of the device or while attempting to clear the nozzle.  Non-dominant hand involved ~75% of the time, with index finger injury most common, followed by middle finger and palm.

Despite benign outward appearance, there is almost always significant underlying damage, and should be considered a SURGICAL EMERGENCY.  Our job as ED providers is to recognize the seriousness of the injury and involve a hand surgeon as fast as possible!

Pathophysiology involves direct trauma resulting in local tissue damage, acute and chronic inflammation, and foreign body granuloma formation.  Tissue ischemia/necrosis from vascular compression, chemical inflammation, and secondary infection can lead to devastating functional outcomes, including amputation.

Key historical details that impact prognosis:

• Time from injury to treatment
• Force of injection (PSI)
• Volume of substance injected
• Composition of injected material (grease, latex, industrial solvent, oil/water-based paint, etc)

Time from injury to treatment is the most important prognostic factor.  Delay of >10 hours significantly increases risk of amputation.  Higher PSI and larger volume of injected material portend greater direct tissue damage.  Hydrocarbon-based substances (fuel, organic solvents, oil-based paint, paint thinners) cause more severe inflammatory reaction and tissue necrosis, with amputation rates >50%.  Grease, latex, and water-based paints re typically less destructive.

Obtain plain films in the ED to rule out coexistent fracture/dislocation.  Some injected materials may appear radiopaque on x-ray and could aide in pre-operative planning.  Administer broad-spectrum parenteral antibiotics in the ED, and update tetanus status.  Control pain as needed, and arrange for emergent orthopedic/hand surgery evaluation.  Transfer to Trauma Center if necessary.  Patient will need emergent operative irrigation and debridement.

Patient in HPI above had excellent functional outcome due to early presentation.  Below is a time-course representation of patient with a delayed presentation, outlining potential damage that can occur.

​Management Pearls:

• Despite benign appearance, underlying injury can be devastating
• Ask key historical details
• Plain films, antibiotics, tetanus, pain control in the ED
• Emergent orthopedic/hand surgeon consultation, DO NOT DISCHARGE HOME!

By Dr. Blake Johnson


References:
1. Aiyer, A. "High-Pressure Injection Injuries." OrthoBullets, 15 Mar 2014. Web. Retrieved 25 Sept 2015, from http://www.orthobullets.com/hand/12104/high-pressure-injection-injuries.
2. Sanford, S. "High-Pressure Hand Injury." eMedicine/Medscape, 12 Nov 2013. Web. Retrieved 25 Sept 2015, from http://emedicine.medscape.com/article/826620-overview.  (multiple images)
3. http://lifeinthefastlane.com/high-pressure-injection-injury/  (image)