Endocrine Abstracts

Polymyalgia Rheumatica (PMR) is a condition of widespread inflammation which mainly affects large muscles manifesting as muscle pain, stiffness and weakness, usually associated with elevated circulating inflammatory markers. Typically PMR responds briskly to the introduction of glucocorticoids but hasty withdrawal can precipitate re-activation of the condition, a message illustrated by our case report in a patient identified with Cushing’s syndrome.

A 52-year-old woman was referred with a year history of lethargy, proximal muscle pain and weakness, poor wound healing, suboptimal BP control and recent weight gain of 10 kg. She appeared clinically Cushingoid and had marked proximal muscle weakness. Cushing’s syndrome was confirmed by biochemical investigation (cortisol 367 nmol/l after high dose dexamethasone suppression test). MRI scanning revealed a left 3.2 cm adrenal adenoma. She received metyrapone prior to left adrenalectomy. There was marked resolution of her symptoms and her blood pressure was more readily controlled. She also lost 7 kg in weight in 2 months.

However, over the forthcoming weeks she experienced reduced energy levels and lassitude associated with progressive neck/shoulder pain. She reported proximal muscle stiffness/weakness and had difficulty combing her hair and getting out of her chair. Recurrence of her Cushing’s syndrome and adrenal insufficiency were both excluded by biochemical testing. A clinical diagnosis of PMR (confirmed by a rheumatologist) was supported by an elevated CRP of 42 mg/l. Prednisolone 20 mg/day was commenced and consistent with PMR, she noticed dramatic improvement within 48 h.

We postulate that the onset of PMR predated the diagnosis of Cushing’s syndrome, but the patients clinical manifestations of the disease were suppressed by endogenous glucocorticoid over-production. Overt clinical presentation with symptoms suggestive of PMR became evident only after surgical resection of the adenoma associated with rapid decline in supraphysiological cortisol levels. The gradual withdrawal of steroids is mandatory in the successful treatment of PMR.