Endocrine Abstracts

Introduction: Dermatomyositis is a chronic, idiopathic inflammatory myopathy that can overlap with rheumatoid arthritis. The immunostimulatory effect of prolactin is suggested by many authors. Herein we report an original association of hyperprolactinemia with a scarce condition: dermatomyositis-rheumatoid arthritis overlap in a young woman.

Case description: A 26-year-old woman with no significant medical history was referred to our department to investigate deterioration of physical condition with myalgia. She was apyrectic and had clinical features of dermatomyositis including Gottron’s papules, heliotrope rash, proximal nail fold erythema, symmetric weakness affecting predominantly the proximal muscles of the legs and arms. Serum creatinin kinase was elevated at 395 UI/l and lactate deshydrogenase levels were at 546 UI/l. The muscle biopsy and the electromyogram confirmed dermatomyositis diagnosis. Respiratory function tests and CT chest were normal. There were no symptoms of infection. Given possible association with neoplasms, exhaustive investigation was performed and showed no underlying neoplastic disease. Since the patient had polyarthralgia and a biological inflammatory syndrome, we suspected the presence of another connective tissue disease. An overlap of dermatomyositis and rheumatoid arthritis was diagnosed as the patient presented symmetric swelling of small joints, morning stiffness, and a boutonniere deformity in the 4^th and 5^th right fingers. Rheumatoid factor was at 80 UI/l and anti-CCP levels were at 15. Menstrual irregularities were reported, therefore hormone tests were performed. They highlighted a hyperprolactinemia at 1136 UI/l and normal levels of FSH, LH and estrogen. Gynecological examination and pelvic sonography showed no abnormalities. The patient was commenced on prednisone 50 mg/day (1 mg/kg), with satisfying clinical and biological evolution. No prolactin inhibitors were prescribed. Prolactin levels were normalized in follow-up and menstrual cycles of our patient became more regular. Pituitary MRI was not performed as the patient lost to follow up.

Conclusion: The effect of hormones on the immune system has been widely described. Many research reported hyperprolactinemia in patients with autoimmune diseases; it might promote the development of autoimmune diseases, leading some authors to suggest some role of dopamine agonists in the therapy of those diseases. More large-scale studies are needed to establish the exact relationship between hyperprolactinemia and autoimmune diseases and effeciency of dopamine agonists in such conditions.