Polymyalgia rheumatica or Lyme disease? How to avoid misdiagnosis in older patients

This case report demonstrates the need to consider Lyme disease in older patients who present with nonspecific signs and symptoms often seen in polymyalgia rheumatica, particularly a markedly elevated erythrocyte sedimentation rate (ESR). ESRs greater than 100 mm/hr are common in polymyalgia rheumatica, but rates higher than 85 mm/hr are also possible in Borrelia infection. Because positive serologic findings for Lyme disease have been noted in patients with polymyalgia rheumatica who have been exposed to endemic areas, differential diagnosis must be based on clinical manifestations. Response to therapy should be monitored closely to confirm the diagnosis and avoid the adverse consequences of inappropriate treatment. The potentially deleterious effect that corticosteroids can have on Lyme disease must be considered in the decision to treat polymyalgia rheumatica.