Patient presents with acute onset left knee pain, swelling, erythema, and warmth, consistent with suspected septic arthritis.  Symptoms onset reported two days prior to presentation, initially characterized as mild discomfort, progressing rapidly to severe pain limiting weight-bearing and range of motion.  Patient reports associated fever, chills, and malaise.  Medical history significant for type 2 diabetes mellitus and recent dental procedure one week prior.  Physical examination reveals marked tenderness to palpation of the left knee joint, decreased range of motion due to pain, and an effusion.  Laboratory studies ordered including complete blood count with differential, erythrocyte sedimentation rate, C-reactive protein, and blood cultures.  Arthrocentesis of the left knee performed, revealing cloudy synovial fluid.  Synovial fluid analysis sent for cell count, differential, gram stain, and culture.  Preliminary assessment suggests septic arthritis of the left knee.  Differential diagnosis includes gout, pseudogout, and reactive arthritis.  Patient admitted for intravenous antibiotic therapy pending culture results.  Initial treatment with broad-spectrum antibiotics initiated, covering gram-positive and gram-negative organisms.  Orthopedic consultation requested for evaluation and potential joint lavage.  Plan to monitor patient's clinical response to antibiotics, adjust treatment based on culture results, and assess the need for surgical intervention.  Diagnosis codes considered include M00.061 for septic arthritis of the left knee.  ICD-10 codes, medical coding, and billing documentation will be finalized upon completion of diagnostic workup and treatment plan.