Diagnostic Challenges in Adolescent Septic Arthritis: A Case Report and Literature Review

Background Septic arthritis of the hip (SAH) is a severe and potentially disabling infectious condition in pediatric patients. Early diagnosis can be challenging due to atypical presentations, including the absence of classical signs of infection such as fever and leukocytosis. This case report explores the diagnostic challenges and highlights the importance of imaging and joint fluid analysis in diagnosing culture-negative septic arthritis of the hip. Case Presentation A 12-year-old boy presented with progressively worsening right hip pain, initially misdiagnosed as transient synovitis. Laboratory findings included The patient presented with a normal white blood cell count (8.56*10 ⁹ /L), but markedly elevated C-reactive protein (CRP, 167.2 mg/L) and erythrocyte sedimentation rate (ESR, 95 mm/h). The synovial fluid analysis revealed an increase in neutrophils, elevated lactate dehydrogenase levels, and decreased glucose levels, while both blood and synovial fluid cultures were negative. MRI revealed bone marrow edema and joint effusion, raising suspicion for septic arthritis. Despite the absence of a confirmed pathogen, clinical presentation, synovial fluid analysis, and imaging findings led to the diagnosis of septic arthritis. The patient underwent arthroscopic lavage and received empirical antibiotic therapy, resulting in significant clinical improvement. Conclusion This case underscores the diagnostic difficulty in pediatric culture-negative septic arthritis, particularly in the absence of fever and with normal white blood cell counts. MRI plays a pivotal role in early detection and assessment of complications. Prompt surgical intervention and empirical antibiotic therapy remain crucial for successful management. Clinicians should maintain a high index of suspicion for atypical presentations to prevent delays in diagnosis and avoid long-term complications.