INTRODUCTION: Interstitial lung disease in dermatomyositis has been well established and occurs in up to 30% of patients, but the occurrence of pneumomediastinum is rare. We report a unique case of dermatomyositis with rapidly progressive interstitial lung disease with spontaneous pneumomediastinum.
CASE PRESENTATION: A forty-four-year-old Latin American woman presents to the hospital with progressively worsening dyspnea over the past two weeks. She had been in good health until she developed a rash over her upper extremities after working in her garden eight months ago. Subsequent symptoms included cough, fever, alopecia, joint pain, weight loss, fatigue and dysphagia. On initial evaluation, patient was diagnosed with systemic lupus erythematosus and prescribed non-steroidal anti-inflammatory medication. She did not improve and sought further care in Mexico. She received high dose steroids with transitory improvement in her symptoms. After returning to Texas, her condition deteriorated, and she was admitted to the hospital. Clinical exam was significant for bibasilar crackles, heliotrope rash, oral ulcers, Gottron's papules, mechanic's hands with hyperkeratosis, and proximal muscle weakness. Chest radiograph revealed ill defined bilateral nodular opacities. High resolution computed tomography demonstrated extensive scattered ground glass opacities along with an incidental pneumomediastinum. Laboratory data was significant for elevated creatine kinase, aspartate aminotransferase and aldolase. Serology included a negative anti-nuclear antibody and anti-Jo-1, but positive anti-Smith, anti-RNP, anti-SS-A and anti-SS-B. Bronchoscopy with transbronchial biopsy revealed mild interstitial fibrosis with hemorrhage but without obvious necrosis or vasculitis. Patient subsequently developed respiratory failure and required mechanical ventilation. Therapy initially included empiric antibiotics and pulse dose steroids. Physical exam and radiographs demonstrated gradually worsening subcutaneous emphysema. Bilateral chest tube placement and pressure control ventilation provided little relief for extensive subcutaneous emphysema. Despite treatment with pulse dose steroids and intravenous IgG, patient expired fifteen days after intubation.
DISCUSSIONS: Pulmonary manifestations of dermatomyositis include aspiration, respiratory muscle impairment, and interstitial inflammation. Common patterns of lung involvement include interstitial pneumonitis, diffuse alveolar damage and bronchiolitis obliterans. Although the etiology of pneumomediastinum remains unclear, it has been postulated to occur: due to interstitial fibrosis with degeneration of alveoli with subsequent bleb formation; vasculitis leading to air leaks; the presence of interstitial lung disease; previous corticosteroid use. Interestingly, cases have been reported without evidence of interstitial lung disease or previous corticosteroid use; thus, the precise etiology remains elusive. Reported age ranges from 20 to 65, and no gender prevalence is noted. Patients may present with dyspnea, cough, neck pain, respiratory failure or without symptoms. Imaging often confirms the presence of mediastinal or subcutaneous emphysema. Concomitant pneumothorax is often not present. Prognosis in patients with interstitial lung disease and pneumomediastinum remains divided. In a report of twenty-one patients with dermatomyositis (mostly Japanese) who developed pneumomediastinum, prognosis was poor with eleven patients dying of respiratory failure(1). A series of eighty-one patients with polymyositis/dermatomyositis associated lung disease identified five cases of acute interstitial lung disease with dermatomyositis, pneumomediastinum and the absence of anti-synthethase antibodies (2). All five cases expired within six months despite intensive immunosuppression. Other cases reports describe recurrent or persistent pneumomediastinum with a benign clinical course. Therapy has been based on individual cases, and it has included steroids, methotrexate, cyclophosphamide, cyclosporine A, azathioprine and surgical pleurodesis with variable success. Interestingly, no cases of pneumomediastinum have been reported in polymyositis.
CONCLUSION: Pneumomediastinum in dermatomyositis remains a rare but established phenomenon. Although its' role in prognosis remains unclear, it does not always suggest a fatal outcome. Although major aspects of this entity have been characterized, a complete understanding of etiology, serologic association, prognosis and treatment continues to evolve.
DISCLOSURE: Saadia Faiz, None.