Evaluation of dystrophic calcinosis in juvenile dermatomyositis and systemic sclerosis

Abstract

Background: Dystrophic calcinosis is associated with juvenile dermatomyositis and systemic sclerosis. Clini- cal diagnosis is performed through the detection of sub- cutaneous, hard nodules. Conventional radiographic studies may demonstrate calcium deposits, however, with very early lesions X-rays may prove insufficient. There are a few studies where scintilliography has been used to identify dystrophic calcinosis. Objectives: To estimate the frequency of dystrophic calcinosis in patients with juvenile dermatomyositis and systemic sclerosis/CREST syndrome. To estimate the concordance between the diagnoses of dystrophic calcinosis obtained by physical examination and scin- tigraphy. Patients and Methods: Observational, transversal and comparative study in which patients of both genders, between 5 and 7 years of age with the diagnoses of juvenile dermatomyositis and systemic sclerosis/CREST syndrome were included in order to detect dystrophic calcinosis by physical examination and scintigraphy. Fisher’s exact test was used to evaluate the association between both diagnostic methods, Kappa test was used to evaluate the level of concordance between both methods and a distribution by group analysis was used to analyze the extent of dystrophic calcinosis with both methods. Sensitivity and specificity for scintigraphic findings in soft tissues, bony protrusions , ribs and vertebrae was also estimated. Results: The frequency of dystrophic calcinosis was 80%. Dystrophic calcinosis was detected through physical examination in 16 patients and through scin- tigraphy in 9 patients. No association or concordance was found between the clinical and the scintigraphic findings. Scintigraphy has a 37.5% sensitivity for the detection of dystrophic calcinosis in soft tissues and 43.8% in bony protrusions, but is ideal for its detec- tion in the ribs. Conclusions: Both, physicial examination and scin- tigraphy are complementary tools for the detection of dystrophic calcinosis.

Keywords

• calcinosis distrófica
• dermatomiosistis juvenil
• esclerosis sistémica progresiva
• centelleografía ósea