X-linked agammaglobulinemia combined with juvenile idiopathic arthritis and invasive Klebsiella pneumoniae polyarticular septic arthritis.

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency disease caused by mutations in the Bruton's tyrosine kinase (BTK) gene. XLA can also present in combination with juvenile idiopathic arthritis (JIA), the major chronic rheumatologic disease in children. We report herein the first known case of a juvenile patient diagnosed with XLA combined with JIA that later developed into invasive Klebsiella pneumoniae polyarticular septic polyarthritis. An additional comprehensive review of XLA combined with JIA and invasive K. pneumoniae septic arthritis is also presented. XLA was identified by the detection of BTK mutations while the diagnosis of JIA was established by clinical and laboratory assessments. Septic arthritis caused by invasive K. pneumoniae was confirmed by culturing of the synovia and gene detection of the isolates. Invasive K. pneumoniae infections can not only result in liver abscesses but also septic arthritis, although this is rare. XLA combined with JIA may contribute to invasive K. pneumoniae infection.