September 2006

A 5-year-old boy was admitted to the hospital for evaluation and treatment of pain, swelling and erythema of his right hand. The history revealed that the problem began as a common paronychia that was noticed about three to four days earlier. There was no history of trauma or insect bites. He was seen in the ED the day prior to admission, where the paronychia was drained (without culture) and 300 mg of Unasyn (ampicillin-sulbactam) was given IV. The next day on follow-up, the area was more erythematous and painful and therefore, he was admitted. His past medical history is unremarkable and immunizations are up to date. Examination revealed normal vital signs and an infected right thumb (figure 1) with erythema extending around to the dorsum of his hand, sparing the palm (figures 2-3). His right axilla was somewhat tender, but no adenopathy was felt. The rest of his exam was normal. Laboratory tests performed included a normal CBC, a culture and Gram stain of the paronychia for bacteria and a culture for herpes simplex.

What’s The Best Treatment?

1. IV Vancomycin
2. IV Nafcillin
3. IV Unasyn
4. IV Clindamycin

Answer

My choice today (2006), pending culture results, is D, clindamycin. He quickly improved and was discharged the next day on oral (PO) clindamycin. The culture revealed methicillin-sensitive Staphylococcus aureus (MSSA) that was penicillin-resistant. The patient was switched to oral cephalexin (Keflex, Advancis) suspension to finish treatment and recovered without complication. Why Keflex? If you have ever tried giving your child an anti-staph penicillin like dicloxacillin or clindamycin suspension, you know how difficult it can be because of the bad taste. Not that Keflex is all that great tasting; but it is much more palatable than the alternatives for children too young to take pills or capsules. If they won’t take the medicine, then it won’t work.

This was one of the few S. aureus isolates from our community that was NOT methicillin-resistant (MRSA). Most paronychial infections are caused by either S. aureus or Streptococcus pyogenes. Considering that most S. aureus isolates are methicillin-resistant, but clindamycin-sensitive, and that clindamycin also treats S. pyogenes, clindamycin is the best choice with which to begin treatment. Also, some are caused by the patient biting the nail and anaerobes may be in the mix, which should be treatable with clindamycin also. Occasionally, the paronychia may be due to gram-negative organisms, especially if the patient’s hands are frequently wet, and the abscess may have a somewhat greenish appearance (figure 4 which grew an Haemophilus species).

Regarding the other choices, if the patient appeared to be septic, or if the infection appeared significantly widespread, then vancomycin (possibly with a second antibiotic, such as ceftriaxone) would be appropriate pending culture results. Let me emphasize the importance of culturing any infection that contains pus. A paronychia is very easy to drain and culture; if it is severe enough to treat with an injection of an antibiotic like Unasyn, then it is especially important to culture. It is as simple as the technique shown in figure 5. Lastly, for the reasons of resistance noted above, neither nafcillin nor Unasyn is appropriate empiric therapy.

All infections involving the hand should be taken very seriously and be treated with intravenous antibiotics and drained by a hand surgeon if suppurative. The nature of the injury that led to the infection should also be taken into account; for example, if it is a closed fist injury (figure 6), one may expect more mouth anaerobes, possibly Eikenella corrodens, to be contributing to the infection. In this case, adding Pfizer’s Unasyn (the drug of choice for Eikenella) to the clindamycin would be appropriate. Unlike most other anaerobes, Eikenella does not respond to clindamycin. If the infection results from a dog or cat bite (figure 7), then Pasteurella multocida should be considered, which is also covered by Unasyn. In fact, Unasyn would be all that’s normally needed for hand infections in the days prior to MRSA ruling the world of S. aureus.

The speed at which the infection progresses may also lend a clue. Hand infections that seem to be getting worse by the hour are more likely to be due to group A streptococcus (GAS), as shown in figures 8–10, which show a 10-year-old whose right index finger was cut by a knife the day before. He presented with a fever of 103.5° F and a 12-hour history of painful swelling of his right hand. The pictures were taken approximately 36 hours after the injury. He had surgical drainage of his hand later that day, and the culture grew group A streptococcus. Pasteurella shares a similar tendency to develop rapidly, whereas Staph infections tend to be slower to develop and progress.

Herpes cultures were obtained because of the similar appearance of Herpes simplex paronychia (Whitlow) and those caused by bacteria (figure 11). Sometime they coexist as shown in figure 12, a boy with a forehead lesion with cellulitis that grew both S. aureus and Herpes simplex.

Commentary

For over 17 years of writing this column, I have often relied on the editorial judgment of Marie Rosenthal. Marie has sought opportunities elsewhere and I will miss her a great deal.

I’m hearing nothing new from my active duty medical colleagues from the war(s). Most military pediatricians have completed more than one tour in either Iraq or Afghanistan. Through their humanitarian service while deployed, these people are doing more to win the hearts and minds of the civilian population in these war-torn areas than all the politicians combined.

As expected, the number of killed and wounded continues to climb. As of this writing (early August), the number of American military killed in Iraq is 2,579, and the number wounded is 18,988. The numbers from Afghanistan are 321 killed and 825 wounded (www.cnn.com).

Please keep in touch at jhbrien@aol.com. For any questions or comments about this column, or to ask about scheduling a speaking engagement, just drop me a note. I will try to answer your letters as quickly as possible.