A puncture wound is a break that occurs in the skin from a foreign object. The foreign object may or may not stay embedded in the skin and structures below the skin. A wound of this nature may occur anywhere on the body but as you can well imagine is very common in the foot. This discussion will relate to punctures of the foot.
Assuming the foreign object is removed, most wounds will heal uneventfully, but a certain percent who delay medical care will develop complications, primarily an infection. More severe complications include osteomyelitis which is a bone infection, a septic joint (infected joint) from penetration of the foreign body into a joint, neurological impairment due to damage to a nerve, or vascular impairment as a result of the foreign body damaging a blood vessel, and loss of function in a certain area due to the penetrating trauma inflicted by the foreign body.
This type of wounds are very common in children, people who work outdoors, at construction sites, and people who do a lot of walking in bare feet.
Initially, the presentation of a puncture wound will vary widely between patients. Some people will know they stepped on something, may or may not been able to remove the object, and have no pain. Others will have trouble walking even though they have no overt sign of infection and of course others will have difficulty walking and their foot will be red and swollen.
In addition to the wound, a person’s medical history comes into play as it relates to wounds of the foot. For example, a poorly controlled diabetic or a patient with poor circulation to the foot is at greater risk for infection. One of the problems with a diabetic is that they may not know they stepped on a foreign object because of diabetic neuropathy, or the inability to feel the bottom of their feet. People with immunosuppressive diseases are also at greater risk for infection and exacerbated problems from a puncture wound. The picture below is that of a puncture wound in between the first and second toe in a diabetic.
Pinpointing the wound is usually easy enough but determining the presence of a foreign body in some cases can be very difficult. In superficial wounds like splinters and broken glass, the foreign body is either protruding from the skin or is just below the outer layer of skin. These wounds are easy to clean. Problems may occur when either the patient has tried to remove the foreign body, may or may not had success, but then comes in and the foreign body has been pushed further into the foot, or the partial remnant left over is more difficult to reach. Additionally, in many cases the patient has been walking around with the foreign body in their foot for days and the pressure of walking has pushed the foreign object further into the foot. Depending on the mechanism of injury sometimes the foreign object is fairly far away from the actual site of the puncture wound.
Knowing where the foreign object is located and how deep it is goes a long way in determining how difficult it will be to remove. Most superficial foreign bodies can be removed in the office, many without anesthesia. The problem arises when it is determined that the foreign object is too deep and to remove it will require a fair amount of dissection. These cases are better treated in the hospital under anesthesia and adequate hemostasis (control of bleeding).
When the foreign body is determined to be deeper in the foot there are a number of diagnostic tests that can be performed to determine the location. The simplest is an x-ray with at least two views. X-rays will spot any metallic objects like nails or pins and even glass depending on the lead content of the glass.
For more difficult objects not seen on x-ray an ultrasound or MRI may be indicated. MRI’s are particularly helpful in not only identifying a foreign body, but also for checking to see if there has been any structural disturbance.
In evaluating a foreign body it is important for the doctor to know the type of material that penetrated the foot and where the accident occurred. A piece of metal from a dirty construction site carries a greater chance of infection then a sewing needle stepped on at home.
Not all wounds require antibiotics. Right now there are no significant studies that suggest routine administration of antibiotics for the prevention of infection in foreign bodies will actually improve outcomes. The decision for antibiotics rests with your doctor. If your wound shows signs of infection like drainage, swelling, redness and pain you are probably a candidate for an antibiotic. Duration of the antibiotic will also be at the discretion of your doctor.
Two common organisms found in puncture wounds are Pseudomonas aeruginosa and methicillin resistant Staph aureus (MRSA). Although most infections do not end up in osteomyelitis, when it does it is usually a Pseudomonas infection. When a puncture wound fails to heal MRSA has to be ruled out.
The organism most associated with puncture wounds is Clostridium tetani which is associated with tetanus.
What about tetanus immunization? Generally, clean minor wounds do not require tetanus innoculation. Wounds that are contaminated with dirt, feces or are deep penetrating wounds may require a tetanus shot depending on the patient’s tetanus history.
If you are uncertain or have had less than 3 doses of Td (adult tetanus and diphtheria toxoids) or TIG (tetanus immune globulin) you will probably require immunization. If you have had your three doses but they were over five years ago, then you too will require additional immunization.
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