Introduction: Dermatomyositis is an autoimmune inflammatory process typically presenting with symmetric proximal muscle weakness preceded by skin lesions. We report a case of dermatomyositis initially presenting with pleural effusion before developing rashes and proximal muscle weakness. Case presentation: A 46-year-old female with no known comorbidities presented with four weeks of anorexia. On work-up, she was found to have bilateral pleural effusion. Diagnostic and therapeutic thoracentesis done draining one liter. Pleural fluid analysis showed exudative character with no presence of bacteria or malignant cells. Intravenous piperacillin-tazobactam 4.5g every eight hours was given for one week but effusion persisted. After 10 days of intravenous antibiotic, antibiotic was shifted to oral cefixime 400mg tab once daily and levofloxacin 500mg tab once daily. However patient developed maculopapular rashes over the face, neck and arms two days after starting the oral antibiotics. The antibiotics were withheld and antihistamine was given for possible drug reaction. No improvement thus oral prednisone 20mg/day for six days was given. After 14 days of oral prednisone, rashes persisted, now with proximal muscle weakness in all extremities associated with the ‘V-sign’ and ‘shawl sign’. The patient was readmitted and work-up showed resolution of pleural effusion. ANA was positive and CKMM level was markedly high. Other rheumatologic tests were unremarkable. Patient was started on Intravenous hydrocortisone 200mg/day and methotrexate 7.5mg/ day once a week. Nine days after initiating intravenous glucocorticoid and methotrexate, patient’s symptoms resolved. Patient was advised for malignancy work-up on follow-up but was lost to follow-up. Discussion: Dermatomyositis initially presents with rashes (100%) and proximal myopathy (95.2%). Interstitial lung disease (ILD) may occur (28.6%), but pleural involvement is rare with only three reported cases and all were associated with ILD. There are no reports of pleural effusion as the initial manifestation. Dermatomyositis is confirmed using the Bohan and Peter Criteria and our patient fulfilled a definitive diagnosis. Glucocorticoids and immunosuppressive drugs are mainstay treatment. Pleural effusion involvement was observed to have good response to treatment, in contrast to ILD which was associated with higher mortality thus should be ruled out in patients with pleural effusion. Conclusion Autoimmune diseases are known for classic manifestations, but may rarely mimic common clinical manifestations thus high index of suspicion is warranted to provide prompt management.
Dermatomyositis ; Pleural Effusion ; Autoimmune Diseases