Chronic seronegative spondyloarthropathy following acute Mycoplasma pneumoniae infection in a human leukocyte antigen B27-positive patient: a case report

BACKGROUND: We report a case of a 30-year-old patient who presented with acute Mycoplasma pneumoniae infection that was complicated by reactive arthritis and asymmetric proximal myopathy and progressed to chronic spondyloarthropathy. Reactive arthritis and sacroiliitis are unusual extrapulmonary manifestations of M. pneumoniae infection, which is a common condition. CASE PRESENTATION: A 30-year-old Greek previously healthy man presented to our emergency department with fever, progressively worsening bilateral lower limb weakness, and asymmetric oligoarthritis. Our diagnosis was based on a positive polymerase chain reaction test for M. pneumoniae using blood and cerebrospinal fluid and magnetic resonance imaging findings that suggested sacroiliitis. Our patient was also found to be human leukocyte antigen B27 positive. His infection was successfully treated with a 14-day course of doxycycline; the arthritis was treated with naproxen and corticosteroids. His arthritis, which restricted his mobility, improved progressively, and he was discharged without any neurological symptoms. CONCLUSIONS: In our case, an acute M. pneumoniae infection eventually progressed to chronic spondyloarthropathy. In our patient, M. pneumoniae infection may represent a random event, or it might be a necessary factor for the development of reactive arthritis, asymmetric proximal myopathy, and sacroiliitis, always in combination with the appropriate genetic background. Extrapulmonary manifestations of M. pneumoniae may occur even in the complete absence of respiratory symptoms, and the diagnosis of unusual complications, such as reactive arthritis, requires high clinical suspicion and extensive investigation.