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A man with arthralgias and skin lesions

Published:January 28, 2021DOI:https://doi.org/10.1016/j.ejim.2021.01.007

      1. Introduction

      A healthy 43-year-old man presented to the Emergency Department with a one-week history of fever, low back pain and arthralgias mainly localized in the right knee. Physical examination revealed painful swelling of the left hand and lower limb (Fig. 1A), non-tender haemorrhagic macular lesions on the soles (Fig. 1B) and signs of right knee arthritis (Fig. 1C). Laboratory tests showed aspecific neutrophilic leukocytosis. A computed tomography of the lumbar region demonstrated a paravertebral mass located at L4-L5 level, which was consistent with spondylodiscitis associated with soft tissue involvement. CT-guided needle aspiration of the paravertebral mass (Fig. 2A) and right knee arthrocentesis were performed, in both cases removing purulent fluid (Fig. 2B).
      Fig 1
      Fig. 1(A) Painful swelling of the left hand. (B) Non-tender haemorrhagic macular lesions on the soles. (C) Left knee swelling.
      Fig 2
      Fig. 2(A) CT-guided needle aspiration of paravertebral mass. (B) Purulent fluid removed from knee joint.
      What is the diagnosis?

      2. Diagnosis

      Staphylococcus aureus community-acquired bacteremia

      3. Discussion

      Cultures of both paravertebral and knee joint fluid, as well as blood cultures, showed methicillin-sensitive Staphylococcus aureus (MSSA). A transesophageal echocardiography was performed in order to rule out infective endocarditis, revealing normal valvular patterns and no vegetations. No identifiable external sources of bacteremia were found. Treatment with oxacillin was started and the patient was transferred to the Infectious Diseases department.
      Staphylococcus aureus is a common cause of community-acquired bacteremia. Bacteremia may be consequent to a local focus of infection, but in about one-third of patients no initial source is identified [
      • Mitchell D.H.
      • Howden B.P.
      Diagnosis and management of Staphylococcus aureus bacteraemia.
      ].
      Patients with community-acquired bacteremia have an increased risk for metastatic seeding with respect to hospital-acquired bacteremia [
      • Lautenschlager S.
      • Herzog C.
      • Zimmerli W.
      Course and outcome of bacteremia due to Staphylococcus aureus: evaluation of different clinical case definitions.
      ]. Metastatic infections are common and may involve virtually any body site. Osteomyelitis commonly affects the vertebral column. Septic arthritis usually affects a single joint and knee appears to be the most common site. Skin manifestations of bacteremia include splinter haemorrhages, subcutaneous nodules (the so-called Osler's nodes) and palmar or solar haemorrhagic lesions (also known as Janeway's lesions) [
      • Mylonakis E.
      • Calderwood S.B.
      Infective endocarditis in adults.
      ]. Staphylococcal bacteremia is a major risk factor for infective endocarditis, especially in patients with abnormal or prosthetic valves; echocardiography is required in all patients in order to rule it out.
      Metastatic infections are critical complications, since they influence the optimal duration of antimicrobial treatment, the prognosis and the possible relapse. There are two key principles guiding the therapeutic strategy: first, identification and removal of all infective foci as soon as possible; second, a targeted antimicrobial therapy that should be long-lasting in patients with persistent bacteremia or with irremovable sources of infection [
      • Thwaites G.E.
      • Edgeworth J.D.
      • Gkrania-Klotsas E.
      • et al.
      Clinical management of Staphylococcus aureus bacteraemia.
      ].

      Declaration of Competing Interest

      The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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