Boy’s foot develops eschar following blunt trauma
What’s your diagnosis?
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A previously healthy 8-year-old boy dropped a 5-pound dumbbell on his right foot. After the accident, there was immediate pain, followed by swelling and erythema.
With ongoing concerns 3 days later, he was taken to the local ED, where his exam was consistent with blunt trauma (Figure 1). He had normal plain radiographs. No lab tests were done, but the ED physician instructed the family to follow up with the primary care physician. Over the course of the next 3 days, a blister had formed, which was debrided by his primary.
Ten days after the injury (4 days later), he was seen again for progressive development of a dark, adherent scablike covering over the area with a rim of erythema (Figure 2). He was prescribed oral cephalexin plus topical mupirocin. Complete blood count (CBC) was normal, and interventional radiology saw the patient the next day for a needle aspiration, revealing blood-tinged fluid. A Gram stain was negative, with cultures pending.
Further history shows that the patient’s immunizations are up to date, with no travel, no fever and no animal exposure. He is in the 2nd grade, and his only outside activity is taking drum lessons for 2 hours per week. The family history is unremarkable, with no unusual infections or illnesses and no pets.
Summary:
1. A healthy, afebrile 8-year-old boy with blunt trauma to the dorsum of the right foot was taken to the ED 3 days later with persistent ecchymosis; X-rays were normal.
2. A blister subsequently formed and was debrided, followed by the development of a black, hard covering about 10 days after the injury, at which time antimicrobial therapy was begun.
3. Lab revealed a normal CBC, and needle aspiration of fluid from under the lesion revealed a negative Gram stain with culture pending.
4. The patient reported no travel, no sick family members, was up to date on immunizations and attends the 2nd grade, spending 2 hours per week taking drum lessons.
What’s your diagnosis?
A. Cutaneous anthrax
B. Ecthyma gangrenosum
C. Staphylococcus aureus ecthyma
D. Vascular injury
Answer and discussion:
The correct answer is D, vascular injury, which was obviously caused by the blunt trauma of dropping a 5-pound weight on a firm body part, ie, the dorsum of the foot. The demarcation of the discoloration and subsequent eschar formation on the foot outlines an area consistent with crushing the underlying fourth metatarsal artery, and likely other smaller vessels between the object and the underlying bone, causing at least partial disruption of blood flow to the overlying skin, resulting in necrosis (Figure 3).
Trauma with eschar formation virtually always implies dead tissue due to vascular disruption. In this case, antibiotics were reasonably given but ultimately unneeded, since there was no evidence of a secondary infection, which should have been accompanied by some drainage, spreading erythema or a positive Gram stain and/or culture on sampling. The eschar gradually was replaced with new tissue 3 months after the injury (Figure 4).
Another clue to a vascular injury is the sharp line of demarcation. The neonate shown in Figure 5 suffered an intrauterine vascular accident, causing the discoloration shown, with sharp lines of demarcation. (Columnist note: You can read more about this neonatal injury in the April 2018 column).
Ecthyma gangrenosum is a term that describes necrotic injury to the skin of an immunodeficient patient, often with cancer, caused by septic emboli and perivascular inflammation. While numerous bacteria can cause this injury, it is most commonly due to Pseudomonas aeruginosa sepsis (Figure 6). The patient in this case vignette was otherwise well, easily ruling out this choice.
Staphylococcus aureus ecthyma (Figure 7) is an uncommon complication of S. aureus bacteremia but can look the same as in this case, with similar resolution and healing, leaving a similar scar. The patient with a S. aureus bacteremia complication should have a history of fever, possible abnormal screening lab tests (CBC) and possibly a source. There are several case reports of S. aureus ecthyma in patients with transient neutropenia (Pechter and colleagues). The patient in this case had a normal CBC. The patient in Figure 7 appeared in the January 2020 column.
Cutaneous anthrax is caused by Bacillus anthracis, a gram-positive anaerobic rod, and is very uncommon in this country. When seen, there is usually a known potential exposure. The most common exposures are occupational, including working with cattle, particularly treating cow hides — such as making drumheads — or shearing sheep or handling wool. At the site of infection, an inflammatory papular lesion develops with underlying coagulation necrosis, followed by blistering and eschar formation over the course of a few weeks. Unlike an injury, anthrax lesions are generally painless. The more dangerous form of anthrax is when it causes a pulmonary infection (inhaled anthrax), which is often fatal if not diagnosed and treated in a timely fashion. Drugs used to treat anthrax are usually penicillin, doxycycline or a quinolone, along with a drug to limit toxin production, such as clindamycin. Antitoxin or anthrax immunoglobulin should be added for pulmonary or other systemic forms (see the CDC’s website for more information). The person making the drumheads out of contaminated cow hide is much more likely to get pulmonary or cutaneous anthrax than the student using the drum. Those at risk of exposure may be given the anthrax vaccine, including veterinarians, or military personnel who are deployed to areas where anthrax spores could be used as a biological weapon. Public health should be notified to investigate the source of any patient with any form of anthrax. For pictures of anthrax, go to DermnetNZ.org, a free site for educational use with hundreds of excellent pictures of dermatologic conditions.
Columnist comments:
I would like to thank future podiatrist Emily McAllister for contributing this case material, documenting the follow - up, researching the subject matter and writing the case, which she did with minimal editing. To accomplish this as an undergraduate implies that she, no doubt, has a very bright future.
The end of the year usually means it’s time for another resolution to be healthier, happier, nicer and do more to help others, etc., etc. As more vaccine-preventable infections are rising, perhaps a good resolution might be to resolve to not offend or run off anti-vaccine - minded parents with stern advice, especially if they are still somewhat “on the fence” — to do so will ensure failure in accomplishing the goal of protecting their child. Perhaps a better approach is to simply say in a kind and understanding voice that you are available and happy to answer any questions they may have should they ever want more information. Our tendency is to “strike” a hard line against such foolishness. However, to them, it’s not foolish at all, and ultimately, the child is the one who may get less quality care in the long run if they end up “doctor shopping” for a like-minded physician. Just something to think about.
My personal resolution is to try to preserve as much memory as possible by living healthier with less stress. As such, over the last year, I chose to end my participation in all CME meetings, such as the IDC Symposium (after 30 consecutive years). I have always found it to be a pleasure to present live versions of this column (and still do). However, the “grind” of preparing cases has increasingly become a struggle. I can still type fast enough, but I frequently cannot remember where I filed pictures. Also, researching and staying focused on a topic has become increasingly difficult. However, because of excellent editing, I can still write this column without too many mistakes in the final format. But in the next year or so, this will also likely come to an end. In the meantime, I welcome anyone with good, publishable pictures to send them to me with a case summary if you would like to see it appear in this column. As in this month’s case, I still enjoy featuring guest columnists from time to time, and welcome anyone interested to get in touch with me to find out how we can make it happen.
In the meantime, please keep in touch.
References:
Pechter PM, et al. Pediatr Dermatol. 2012;doi:10.1111/j.1525-1470.2011.01427.x.
CDC. Anthrax information for healthcare professionals. https://www.cdc.gov/anthrax/healthcare/index.html. Accessed Dec. 16, 2022.
For more information:
Brien is a member of the Healio Pediatrics Peer Perspective Board and an adjunct professor of pediatric infectious diseases at McLane Children's Hospital, Baylor Scott & White Health, in Temple, Texas. He can be reached at jhbrien@aol.com.