Septic Arthritis and Osteomyelitis Caused by Pasteurella multocida

Discussion

Cat bites often are the source of Pasteurella species infections because the bacteria are carried by more than 90% of cats.¹ These types of infections can cause septic arthritis, osteomyelitis, and deep subcutaneous and myofascial infections because of the sharp and narrow morphology of cat teeth. The infections can progress to necrotizing fasciitis and myositis if not recognized early, as was the case with our patient. Prophylactic antibiotic administration for animal bites is controversial and is not a universal practice.^1,2Pasteurella bacteremia is an atypical progression that occurs more often in patients with pneumonia, septic arthritis, or meningitis. Cases of Pasteurella sepsis, necrotizing fasciitis, and septic arthritis have been reported.^3-7 However, associated progressive septic arthritis and osteomyelitis, despite initial clinical improvement, have not been reported. Severe infection (ie, sepsis and septic shock) can occur in infants, pregnant women, and other immunocompromised patients.⁷ Immune suppression of our patient with steroid medication for poison sumac dermatitis likely contributed to the progression and systemic spread of an initially benign cat bite. Before prescribing steroids, it is imperative to ask about exposures and encourage patients to seek prompt medical attention with worsening or new symptoms. Healthy individuals rarely develop bacteremia; however, in these cases, mortality remains high at approximately 25%.^4,6

The clinical course of this case emphasizes the need for vigilance and thoroughness in obtaining histories from patients presenting with seemingly benign complaints, especially in vulnerable populations, such as infants, pregnant women, and immunocompromised adults. In this case, the progression of symptoms might have been avoided if the patient’s dermatitis had been treated conservatively or with topical rather than systemic steroids.