An 86-Year-Old man with Septic Arthritis of The Knee

Department of Medicine/Infectious Disease, State University of New York Upstate University, Syracuse, New York, USA Correspondence: Dr Tasaduq Fazili, Department of Medicine/Infectious Disease, State University of New York Upstate Medical University, 725 Irving Avenue, Syracuse, New York 13104, USA. Telephone 315-464-9360, fax 315-464-9361, e-mail fazilit@upstate.edu Case presentation An 86-year-old man with a medical history significant for an aortic valve replacement and pacemaker insertion >20 years previously developed a stress fracture of the left leg, which was placed in an immobilizer cast. One week later, he developed progressive left knee swelling and was admitted to the hospital. A physical examination was significant only for a grade 2 (of 6) systolic murmur over the aortic area, and mild swelling and tenderness of the left knee. The surrounding skin was not erythematous. He exhibited leukocytosis with a white blood cell count of 15.1×109/L. An aspirate of joint fluid from the left knee revealed a white blood cell count of 12.9×109/L with 82% neutrophils. A Gram-stained smear of the joint fluid revealed many white blood cells with no bacteria. Culture of this aspirate for bacteria and fungi was negative. A bone scan showed increasing uptake in the left tibia, suggestive of osteomyelitis. The patient was discharged on four weeks of ceftriaxone (2 g intravenously once per day) for presumed bacterial septic arthritis/osteomyelitis. He presented three weeks later with increasing left knee pain and swelling. A joint washout of the knee and surgical debridement of the proximal tibia was performed. A Gram stain (Figure 1) and modified acid-fast stain (Figure 2) of the joint fluid are shown.