Polymyalgia Rheumatica Presenting as Nocturnal Pyrexia of Unknown Origin: A Case Report

Background. Polymyalgia rheumatica (PMR) is a rheumatic disorder characterized by musculoskeletal stiffness and pain, primarily affecting the shoulder, neck, and hip areas. It is more common in females, with the peak incidence usually after the age of 70. Case Report. A 74-year-old man presented with a two-month history of low-grade nocturnal fever up to 100oF (37.7oC) which did not respond to multiple courses of antibiotics. There was unintentional weight loss of 5 kg and mild shoulder stiffness. The patient had a history of Type 2 diabetes mellitus treated with 34 units of insulin (Humulin 70/30) daily and active smoking of 40 pack-years. On examination, mild tenderness of both shoulder girdle muscles and discomfort on external rotation were noted. The initial blood work-up revealed raised erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. Serologies for syphilis, human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) were negative. Given the negative results of infective and malignancy screening, along with raised inflammatory markers and mild shoulder stiffness, a diagnosis of PMR was made and a trial of prednisolone was initiated, resulting in the resolution of symptoms. Conclusions. The present case report highlights the importance of thoroughly investigating all differential diagnoses of pyrexia of unknown origin, regardless of the patient's ethnic origin, to facilitate timely diagnosis.