By: Chase Hamilton, PGY3
Reviewed by: Brian Ault, DO
High-pressure injection injuries are rare injuries that are typically characterized by small puncture wounds whose severity is easily underestimated by physicians and patients. These injuries result from equipment malfunction or misuse that eject a pressurized material with enough force to penetrate human skin. The force is typically generated by the machinery is 3,000 to 10,000 pounds per square inch (PSI). A force of 100 PSI is sufficient to break the skin.
Most commonly high-injection injuries occur to the non-dominant hand. These injuries are uncommon yet have high morbidity. The rate of injury is related to the material injected. Studies have shown amputation rates of the affected limb as high as 50% for organic solvents 1. Even if debridement occurs within 6 hours for paint thinner, jet fuel, petrol, or oil the amputation rate is still 38%, compared to 58% amputation rate when treatment occurs over 6 hours. High caustic agents like turpentine and paint solvents, along with higher injection pressures have an amputation rate of about 80% even with appropriate care 2. Organic solvents include paint, paint thinner, diesel fuel, jet fuel, oils, etc.
The most commonly injected substances in order of commonality are paints, grease, paint solvents, fuel oils, air and water 3. Even small amounts of injected material may be sufficient to cause compartment syndrome. Literature supports that air and water-based solvents have low risk for poor outcomes or need for surgical debridement or washing. Grease results in inflammatory responses but has a low risk for amputation. Paints cause severe inflammation and high amputation rates 4. Diagnosis requires careful history and wound inspection. Treatment will always necessitate surgical consultation and frequently surgical debridement.
The pathophysiology of the injuries include four main components; initial injury, chemical irritation, inflammation and secondary inflammation. The tissue damage may be chemical or mechanical in the initial injury. The nature of the chemical or substance injected will dictate the severity of edema and inflammation. The injected material creates a small open wound and passes through the tissue and neurovascular structures. It causes traumatic tissue dissection that can lead to compartment syndrome due to the volume of secondary edema and inflammation 5. Clinical condition can rapidly deteriorate secondary to the aforementioned factors impairing circulation, destroying tissue and leading to increased susceptibility to infection.
There are 3 phases of symptoms 6. The Acute phase occurs within 4-6 hours. Symptoms include swelling, anesthesia and vascular insufficiency. The intermediate phase is characterized by the development of oleomas (lipogranulomas) at the injection site and throughout the affected tissues. These are the body’s natural response to the foreign material. The late phase is characterized by skin breakdown over the oleomas leading to ulceration and sinus formation causing secondary infection. Within 12 hours the limb can develop tissue ischemia and necrosis.
Management of high-pressure injection-injuries can involve plain film x-rays of the effected limb. The radiographs may be useful to detect spread of radio-opaque dyes or paints as well as tissue dissection plains caused by the foreign material. The affected area may be splinted in a neutral position and elevated to prevent further spread of injected material. Orthopedics or hand surgery must be emergently consulted. Nonoperative therapy may be an option for air and water injection. Operative therapy is required in the majority of patients, however. Immediate debridement is associated with improved outcomes 5. A delay of 10 hours from time of injection is associated with higher rates of amputation.
It is also recommended to update tetanus status and provide broad-spectrum antibiotics. Necrotic tissue of the affected limb is a nidus for infection and acts as a culture medium for bacterial growth. The antibiotics should include gram positive and negative coverage. Importantly, the physician should provide systemic analgesia but avoid digital blocks and ice due to high pressure in the extremity and already diminished perfusion 7.
Delayed treatment increased risk of postoperative infection. It is advised to push for early surgical intervention. Injection injuries are a true surgical emergency.
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