A severe case of paediatric group A streptococcal osteomyelitis in varicella

We here report an unusual paediatric case of streptococcal osteomyelitis with a severe outcome as a complication of varicella. A 15-month-old girl with a 3-day history of varicella rash was admitted to our Paediatric Department because of high fever, pain and joint immobility of her right elbow and left ankle. Upon admission the patient presented pustules with highly infected lesions on her back, trunk, arms and face. Physical examination revealed marked swelling with diffused tenderness and local warmth at both the right elbow and the left ankle. The patient at admission had a leukocyte count (WBC) of 17,940 ll, C-reactive protein (CRP) of 17.15 mg/dl (normal value \0.5 mg/dl) and erythrocyte sedimentation rate (ERS) of 50 mm/h (normal value \20 mm/h). The humoral immune response was normal [immunoglobulin A (IgA) 107 mg/dl, IgG 925 mg/dl, IgM 182 mg/dl) as were the Tand B-cell subsets (CD3? 74%, CD4? 44%, CD8? 23%, CD19? 18%). Empirical antibiotic therapy with ceftriaxone and amikacin was prescribed. Conventional X-ray revealed swelling at the right elbow, left wrist and feet as well as a fragmented and irregular profile of the right ulna distal metaphysic and the left fibula. Magnetic resonance imaging (MRI) of the elbow revealed massive inflammation of the joint on the left side, with involvement of the surrounding soft tissues (Fig. 1). Bone scintigraphy showed increased activity in the right elbow, left fibula and tibia, consistent with osteomyelitis. Three days after admission, ceftriaxone and amikacin were replaced by ampicillin, owing to a positive blood culture for Group A beta-hemolytic streptococcus(GABSH). Two weeks following the initiation of the ampicillin treatment, laboratory tests revealed the WBC count to be 11,000 ll, CRP 4.63 and ERS 100 mm/h. Due to the lack of improvement in the patient’s clinical condition, ampicillin therapy was changed to treatment with linezolid on the basis of the susceptibility testing. This led to pain relief and a decrease in the swelling. Four weeks after the initiation of linezolid therapy, the patient was discharged with oral administration of linezolid. However, 15 days later, the patient was readmitted due to right elbow pain and swelling. At admission, the WBC was 11,200 ll, CRP 0.08 mg/dl and ERS 10 mm/h. Radiological examinations (X-ray and MRI) revealed bone destruction of the ulna distal metaphysic, compatible with destructive osteomyelitis. The residual proximal stump was diverted externally, and both the lamellar and diaphyseal distal stumps were fragmented (Fig. 2). The orthopaedic physician intraoperatively reduced the anterolateral dislocation of the right radius and put it into a cast. No cultures or other microbiological tests were performed during surgery. One month following the surgery, X-ray examinations showed severe right ulna destructive outcomes, with just a minimal residual proximal and distal fragments. Six months later, an X-ray showed no further radiological modifications. Varicella complications are rare, but in some patients they may be severe, requiring hospitalization [1–3]. The frequency of varicella infection complicated by invasive GABSH disease in children has been documented to be 6–17% [3–5]. Recently, numerous studies have documented an increasing incidence and severity of GABSHS infections [2, 6, 7]. E. Bozzola (&) A. Krzystofiak L. Lancella A. Quondamcarlo A. Villani Department of Paediatrics, Paediatric and Infectious Disease Unit, Children Hospital Bambino Gesu, Rome, Italy e-mail: elenabozzola@libero.it