P0909 - Why Did The Chicken Cross The Hip Joint?

INTRODUCTION
The typical pathogens causing osteomyelitis infections in children under 4 years old are Staphylococcus aureus, Streptococcus pyogenes, Streptococcus pneumoniae, and Kingella kingae. This case presents nontyphoidal Salmonella (NTS) right hip osteomyelitis and septic arthritis in a healthy child. Salmonella osteomyelitis constitutes only 0.45% of osteomyelitis cases amongst immunocompetent children without hemoglobinopathies.

CASE REPORT
2-year-old male with history of perirectal abscess presented with three days of fever and right lower extremity pain. History revealed RLQ abdominal pain and emesis one day prior to admission (PTA) and he played in chicken water trough two weeks PTA. Patient was febrile and tachycardic. Labs notable for CRP 10.7 mg/dL and CK 3964 unit(s)/L. His right leg was flexed and externally rotated and ROM was restricted due to pain with refusal to bear weight. Initial right hip I&D revealed purulent fluid. Empiric IV ceftriaxone and clindamycin were initiated. Hip cultures returned positive for salmonella species. Imaging revealed right hip septic arthritis, right femoral and ischial osteomyelitis, and myositis. Despite targeted antibiotic therapy, he had persistent fevers, elevated CRP, and no clinical improvement. His course prompted a total of five hip/pelvis MRIs, four aspirates, seven washouts and an expanded antibiotic regimen. Further debridement revealed a secondary infection with Candida albicans, which was treated with antifungals. Ultimately, intraarticular cefepime and amphotericin B were administered. After six weeks of hospitalization, he was discharged home on IV ceftriaxone and oral fluconazole.

DISCUSSION
This was a complicated course of NTS osteomyelitis and septic arthritis in a child with normal immunologic and hematologic workup. Exposure was most likely water from the chicken trough. He presented with GI symptoms PTA, which is consistent with previous cases indicating that NTS musculoskeletal infections have a higher likelihood of associated GI symptoms compared to Staph aureus musculoskeletal infections. Previous cases the majority of treatment regimens included multiple surgical debridements and IV antibiotics with patients having complete recovery without chronic sequelae. Due to our patient’s prolonged illness, he required a non-traditional treatment approach with intra-articular antimicrobials. At his three month follow up, he presented with an unstable gait with hip subluxation. We expect he will have increased morbidity with orthopedic complications related to this infection.

CONCLUSION
Salmonella osteomyelitis has no distinguishing clinical or radiological features, therefore, it is important to consider salmonella as a possible pathogen in immunocompetent children. Currently, there is no standard practice in treating this condition. Previous cases revealed that duration of treatment ranged from 5 weeks to 6 months and those that combined surgical debridement and IV antimicrobials provided more favorable outcomes. Due to the rarity of NTS causing musculoskeletal infections in healthy children, targeted interventions may be delayed and incomplete duration of treatment may cause poor outcomes.