O steomyelitis and septic arthritis are uncommon infections in neonates. However, because the potential for permanent disability and overwhelming sepsis is significant, complications of bones and joints infections in neonates are important. Group A b-hemolytic Streptococcus is a rare pathogen in the initial month of life. This case illustrates the link between neonatal osteomyelitis, septic arthritis, and bacteremia.
CASE REPORTA 3-week-old immunocompetent female was admitted to the hospital for fever and leg pain/swelling. She was a former 38-week gestation infant with no infectious risk factors at birth. She was discharged from the hospital on day of life 2 and had been gaining weight appropriately at home. On the day of admission, the family noted the patient's right leg was swollen and tender; she was increasingly sleepy and had a rectal temperature of 38.88C. Her parents and half-sister were healthy. The patient presented to the primary care physician who confirmed the findings, and hospital admission was arranged.Vitals signs included rectal temperature 40.38C, respiratory rate 58 breaths/min, heart rate 154 beats/min; blood pressure 90/ 60 mm Hg. Oxygen saturation was 96% on room air. Physical examination revealed a tired appearing infant, who was looking about and acting hungry. Her HEENT, cardiac, genital, and abdominal examinations were unremarkable. Her lungs were clear, but moderate subcostal retractions were appreciated. Distal pulses were intact. The extremity examination revealed a swollen, erythematous, and tender right thigh ( Figs. 1 and 2).Laboratory reported a hemoglobin of 10.8 g/dL, a white blood cell count of 41.5 10 3 /mL (with 69% polymorphonuclear neutrophils, 12% band forms, and 10% lymphocytes), and a platelet count of 700 Â 10 3 /mL. Blood smear was not worrisome. Serum electrolytes and glucose were normal. Urinalysis was negative. Cerebral spinal fluid showed no red blood cells, no white blood cells, and normal glucose and protein. Blood, urine, and cerebral spinal fluid were collected for culture.A right femur film (Fig. 3) demonstrated a defect at the lateral portion of the distal metaphysis. The cortical bone was disrupted, and there was a ragged-edged lesion. No obvious fracture was appreciated. Orthopedics was consulted; the patient was escorted to the operating room for biopsy, culture, and irrigation. Twenty milliliters of frank pus was drained from the knee joint. Initial Gram stain of the knee aspirate confirmed gram-positive cocci in chains and clusters. Intravenous ceftriaxone and vancomycin were initiated.The patient remained stable following antibiotics and surgical drainage. Six hours after the blood culture was collected, it was positive for gram-positive cocci in chains. The blood and the knee aspirate cultures grew group A b-hemolytic Streptococcus, which was sensitive to vancomycin, ceftriaxone, penicillin, chloramphenicol, and clindamycin. Antibiotics were simplified to intravenous ampicillin. A repeat blood culture was negative. The urine and CSF cultures were neg...