Elevated Procalcitonin in Acute Pseudogout Flare: A Case Report

An 86-year-old male presented to the emergency department with fevers and tachycardia. Given concern for sepsis, a broad infectious workup was pursued. Though no source of infection was identified, the patient was found to have an elevated procalcitonin level. The patient subsequently developed painful joint effusions of the knees, which on arthrocentesis were consistent with calcium pyrophosphate deposition (CPPD) or “pseudogout”. His symptoms of fevers and arthralgias resolved with anti-inflammatory agents. CPPD is a known cause of systemic inflammatory response syndrome (SIRS) in elderly patients. Procalcitonin has been studied as a biomarker for distinguishing infectious from non-infectious causes of SIRS, although its use in CPPD and other crystal arthropathies is not well-defined. The current case is the first to describe elevated procalcitonin specifically attributable to acute pseudogout flare and highlights the need for further study of this biomarker in non-infectious, pro-inflammatory states.