How To Diagnose And Treat Foreign Body Injuries

Author(s): 
By Tamara D. Fishman, DPM

Puncture wounds caused by foreign bodies can be deceptive in appearance. This is because many show little or no signs of external damage, yet they may have caused a serious internal injury. Some of the more common objects that cause these injuries include nails, pins or tacks, wood, glass and thorns. There is usually little bleeding from puncture wounds and these wounds seem to close almost immediately.

However, this does not mean treatment is not necessary. Puncture wounds do have a risk of becoming infected. The object that caused the wound may carry spores of tetanus or other bacteria, especially if the object was exposed to the soil.
Always ask the patients if they can recall when they received their last tetanus shot. The patient will need a tetanus shot if it has been more than 10 years since the last shot or if the last tetanus shot was more than five years ago and the wound has been contaminated by dirt.
You should obtain a detailed medical history and try to determine what caused the puncture wound and the relative cleanliness of the penetrating object.
Additionally, you should discuss the type of footwear the patient was wearing at the time of the injury. Any pieces of shoe or clothing can be forced into the wound and increase the potential for a retained foreign body.

When you examine the patient, cleanse the surrounding skin and carefully inspect the wound with good light and adequate time. Examine the lower extremity for signs of a deep infection such as swelling and pain with motion of the toes. You should also test for loss of sensory or motor function, although this is unlikely to have been caused by a foreign body-related puncture wound.

Key Pointers On Diagnostic Modalities
If there is a question as to whether the object may have broken off in the tissues, obtain a radiograph. This is usually the first diagnostic option one would use to identify a foreign body. Radiopaque objects such as glass, metal and stone will be detectable via an X-ray. However, be aware that the size of the glass may be a limiting factor for detection.
If the objects are plastic, aluminum or wood, these can be radiolucent and would require an ultrasound, computed tomography (CT) or MRI. Obtaining a CT gives you the ability to identify radiolucent objects and locate the three dimensional position. CT seems to be the modality of choice when it comes to identifying wood although xeroradiography is reportedly an excellent modality for identifying wooden foreign bodies. However, keep in mind that the longer the wood is surrounded in the tissue, the more difficult it may be to detect.

Essential Treatment Considerations
The pathophysiology and management of a foreign body wound is dependent upon the material that has punctured the foot, the location, depth and time of presentation, footwear and underlying medical conditions of the patient.

When splinters penetrate the skin, the patient will usually feel an immediate sensation of pain and can often see the splinter in or right under the skin. Usually, there is only a small amount of bleeding or no bleeding at all.
In some cases, though, the patient may not even notice the splinter until an infection develops. Also keep in mind that some splinter injuries can occur not only when someone steps on the splinter but slides his or her foot forward as well. Doing so may allow the foreign body to become deeply lodged into the tissues. Large splinters that interfere with sensation or movement may have the potential for creating deep puncture wounds that may impact nerves and tendons. Splinters are full of germs. If the splinter is not removed, an infection or an allergic response may occur.
Needles can become embedded under any skin surface, but these injuries generally occur when a patient has stepped on one while he or she was walking or running barefoot on a carpeted floor. These patients will typically complain of pain upon weightbearing. When you do your clinical examination, you may see a small puncture wound at the point of entry and a portion of the needle may be palpable as well.

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