A 2 year old with stiff neck and back- is is polymyositis?
Author:
Pediatric Oncall
Question
A 2 years old girl presented with progressive swelling over neck and back since 15 days with inability to move neck and back. She had a fall on her occiput 1 month back. She had right sided congenital torticollis since birth due to sternomastoid tumor. On examination, she was pale and had spasm with stiffness of muscles of upper back & neck with no movements. Congenital right sided torticollis was present. Other joints examination was normal. Other muscle groups were normal. Systemic examination was normal. Her hemoglobin was 7.7 gm/dl, with WBC count of 10,700/cumm [46% neutrophils, 48% lymphocytes, 3% monocytes, 3% eosinophils], platelet count was increased (6,10,000/cumm) and ESR was 3 mm at end of 1 hour. MRI spine and neck showed diffuse patchy hyperintensity in neck muscles, paraspinal, trapezius, scalene group of muscles on T2 weighted images. Intermuscular and subcutaneous fat showed hyperintensity on T2 fat saturation images suggestive of inflammation and polymyositis. Vertebral bodies and joints were normal. Her EMG/NCV was normal. Thyroid function tests and autoimmune workup was normal except ANA was positive [1:40 titre]. Autoimmune markers such as RNP-SM Antibody, Centromere Antibody, Scl-70 Antibody, Lupus anticoagulant, Anti dsDNA. Anti phospholipid IgM & IgG were negative. Muscle biopsy showed inflammatory changes in the muscle tissue without localization. In view of polymyositis on MRI and muscle biopsy, she was treated with IV Methyl Prednisolone for 3 days followed by oral steroids. However there was no improvement. A work up for bleeding disorder in view of history of fall was also negative. On follow up after 15 days, her condition has remained the same.
What is the diagnosis? How to proceed further?
Expert Opinion :
She was suspected to have Fibromyositis ossificans progressiva. Parents could not afford to do the genetic test.