Ostemyelitis is a well-known yet debilitating complication of puncture wounds involving the feet; Pseudomonas aeruginosa is isolated in the majority of cases. The importance of recognizing this entity cannot be overemphasized, given the destructive nature of this infection as well as the strongly recommended role of early surgical intervention. A nail puncturing the foot through a sneaker has been reported so often that it is widely believed that there is something unique to the construction of the sneaker that predisposes to Pseudomonas colonization. There have been no reported cases known to us that have developed after plantar puncture wounds through rubber sandals. We believe that our case is instructive in that it prompts us to reconsider our assumptions regarding osteomyelitis after puncture wounds of the feet.
Case report. AM is an 8½-year-old African-American male who was well until 1 month before presentation when he stepped on a rusty nail embedded in a piece of wood. The nail pierced the rubber sole of his sandal and entered the plantar surface of the patient's left heel to a depth estimated by the mother to be about ½ inch. The mother removed the nail and took him to an urgent care center where they recommended Epsom salts and water soaks two to three times a day. Reportedly no irrigation was done, and the patient was not treated with antibiotics. He had received a tetanus toxoid booster 4 years before this injury.
During the next 2 weeks the child experienced insidious onset of left heel pain. He began to avoid weight bearing on the left heel and there was intermittent swelling. Two weeks before admission he was taken to the Johns Hopkins Hospital Pediatric Emergency Department where he was afebrile and had minimal swelling in the left ankle and foot. No erythema or warmth was present but there was point tenderness with palpation of the left calcaneus. Radiographs revealed no fracture or foreign body, but there was some soft tissue swelling around the calcaneus. A diagnosis of puncture wound with secondary hematoma was made, and the patient was discharged with instructions to clean the puncture wound thoroughly at home. He was not treated with antibiotics.
During the next 2 weeks before admission he had increased pain in the left ankle. Three days before admission he developed warmth and redness in the left ankle. There was no history of fever, left leg pain, rash or other joint pain. He presented to the Johns Hopkins Hospital Pediatric Emergency Department for evaluation.
On examination he was afebrile and looked well. He had mild to moderate left ankle swelling with decreased range of motion. Tenderness was elicited with deep palpation of the left heel, and erythema was noted posterior to the medial malleolus. There was no discharge in the area. No inguinal lymphadenopathy was noted. Laboratory results included a white blood cell count of 6700/mm3 and an erythrocyte sedimentation rate of 90 mm/h. Radiographs of the left foot were interpreted as showing soft tissue swelling over the calcaneus and around the calcaneal apophysis. He was subsequently admitted with a diagnosis of osteomyelitis.
In the hospital oxacillin was started intravenously and a bone scan showed increased blood flow and blood pooling, as well as increased isotope uptake by bone in the left calcaneus. Comparison films of the right foot were then obtained, and it became obvious that there was extensive periosteal reaction in the left posterior calcaneus. On Hospital Day 3 the patient underwent debridement of the left calcaneus. Extensive destruction of the growth plate was noted. Cultures of bone grew P. aeruginosa. Antibiotics were changed postoperatively to treat Pseudomonas infection and continued for 6 weeks because of the extensive bone destruction observed at the time of surgery.
Discussion. Osteomyelitis is a relatively common complication of plantar puncture wounds in children, with an incidence ranging from 0.6 to 1.8%.1 The most common pathogen is P aeruginosa, accounting for 93% of isolates in one large series.1 The usual scenario in children involves a nail that punctures a shoe, almost always a sneaker. Within 2 to 3 weeks there is onset of heel, foot, or ankle pain, often associated with weight bearing. Most patients are afebrile and nontoxic appearing. Tenderness and swelling are present, and laboratory results reveal an elevated erythrocyte sedimentation rate, but usually a normal white blood cell count.2
A number of studies have been done to elucidate the source of P. aeruginosa.3-5 According to one study Pseudomonas grows well in the moist inner layers of the sole of an actively used tennis shoe, whereas it does not grow in new, unused shoes or in old, discarded sneakers.5 The microbiology of the plantar surface of the foot as well as the inner surface of the sneaker is much less consistent; one study reported a 1% incidence of Pseudomonas on the surface of the foot and no organisms on the inner surface of the sneaker.3 It has been hypothesized that the unique construction of the sneaker provides a good growth medium for Pseudomonas. During active use the inner layers of the sole become moist and allow for the growth of the organism; the microbe is then inoculated into the foot by the nail puncture.
Other studies have not shown a high incidence of Pseudomonas colonization in leather-soled or other non-sneaker shoes.4 Despite this and the fact that there has been little recovery of this organism from the plantar surfaces of children's feet, Pseudomonas osteomyelitis has been reported after plantar puncture wounds to bare feet as well as through non-sneaker type shoes.6 Whether our case occurred because of Pseudomonas colonization of the foot, of the rubber sole of the sandal or of the nail cannot be determined. We present this case of Pseudomonas osteomyelitis after a plantar puncture wound through a rubber sandal as an illustration that sneakers are not unique in the development of this infection. Surgical debridement of affected bone and cartilage has been shown to prevent debilitating complications from this infection. Appropriate antipseudomonal antibiotic therapy should be given and surgical consultation should be sought for children presenting with symptoms and signs of osteomyelitis after a puncture wound through any type of footwear.
Prantik Saha, M.D.; Catherine A. Parrish, M.D.; Julia A. McMillan, M.D.
Children's Medical and Surgical Center
Johns Hopkins Hospital
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