Interstitial lung disease associated with polymyalgia rheumatica during tapered steroid treatment: Case report

Rationale: Polymyalgia rheumatica (PMR) is one of the common inflammatory disorders in elderly population. Although the relationship between PMR and giant cell arteritis is well recognized, lung involvement in PMR are rare. Here, we report a case of interstitial lung disease (ILD) associated with PMR, with the progression of respiratory manifestations during steroid therapy. Patients concerns: A 90-year-old woman was admitted to our hospital with dry cough and abnormal shadows on chest radiography. The patient was in a stable medical state until 4 months earlier, when she recognized bilateral shoulders and pelvic girdles shoulder pain and stiffness. She was diagnosed with PMR and initiated with a daily dose of 15 mg prednisolone, which led to rapid symptom alleviation. During the tapering and discontinuation of prednisolone, a chest radiograph revealed abnormal shadows in both lung fields, and the patient was referred and admitted to our hospital for further examination. Diagnosis: On admission, she was found to have re-elevated levels of C-reactive protein matrix metalloproteinase in addition to the stiffness of proximal extremities. Nonspecific interstitial pneumonia-like ILD was considered to be associated with PMR based on the findings of high-resolution computed tomography. Finally, the diagnosis of PMR complicated with ILD was established. Intervention: Intravenous methylprednisolone (250 mg/day for 3 consecutive days) was administrated and be followed by moderate doses of steroids (prednisolone 0.8 mg/kg). Prednisolone dose was gradually tapered (2 mg reduction every 2 weeks) and the dose was reduced to the maintained dose (12.5 mg/day). Outcomes: Steroid treatments resulted in the improved her PMR-related symptoms and respiratory symptoms as well as the resolutions of the pulmonary interstitial shadows. Lessons: This case report suggests that PMR is one of the causes of concomitant ILD and that both conditions can occur simultaneously. PMR complicated with ILD is rare, however, it should be considered as a possible diagnosis when patients with PMR present with respiratory symptoms during the tapered steroid therapy.