Shrinking lung syndrome with hypercapneic respiratory failure responsive to mycophenolate mofetil and systemic steroids.
Bachert H, Bazan L, and Thavarajah K. Shrinking lung syndrome with hypercapneic respiratory failure responsive to mycophenolate mofetil and systemic steroids. Am J Respir Crit Care Med 2017; 195.
Am J Respir Crit Care Med
Shrinking Lung Syndrome (SLS) is a rare complication of Systemic Lupus Erythematosus (SLE) characterized by progressive dyspnea, pleuritic chest pain, diaphragmatic elevation, and a restrictive defect without parenchymal abnormalities. We present a case of SLS to highlight this rare manifestation of SLE and potential modes of therapy. Case Report A 35 year old woman with SLE with manifestations of Raynaud's syndrome, serositis with prior pericardiocentesis, oral ulcers, lower extremity ulcers, and antiphospholipid antibody syndrome presented to the hospital with severe progressive dyspnea, pleuritic left chest pain, and 1 year of nonproductive cough. Her immunosuppression consisted of Mycophenolate Mofetil (MMF) 1000 mg twice daily and prednisone 20 mg daily for three months. Physical exam was remarkable for tachypnea, tachycardia, exertional hypoxia, bibasilar diminished breath sounds without wheeze or crackles, holosystolic murmur with regular rate and rhythm, and healing lower extremity ulcers. ABG showed CO2 56 and pH 7.34. Laboratory values were notable for C3 84(L), C4 29, Anti-dsDNA negative, sedimentation rate 45 (H), C-reactive protein 6.7(H), and room air arterial blood gas pH 7.34, pCO2 56, pO2 99.1. Chest CT revealed bibasilar atelectasis with pleural thickening without pulmonary artery filling defects. Echocardiogram showed a normal ejection fraction and pulmonary artery pressure. Pulmonary function tests (PFTs) showed severe restriction with impaired gas transfer. She was diagnosed with SLS on the basis of severe restriction without parenchymal abnormalities. Bi-level positive airway pressure (BIPAP) was prescribed for chronic hypercapneic respiratory failure and obstructive sleep apnea (apnea hypopnea index of 10). The MMF dose was increased to 1500 mg BID, and prednisone was later slowly weaned. Her dyspnea, left-sided chest pain, and severity of restriction significantly improved. Her exertional hypoxia and chronic hypercapneic respiratory failure resolved and have not recurred during 3 months off BIPAP. Discussion The proposed mechanism of SLS is diaphragmatic myositis or myopathy causing elevation of the diaphragms and decreasing lung volumes. Chronic pleural inflammation may also impair deep inspiration leading to parenchymal reorganization and decline in lung compliance. While data are limited, immunosuppressive therapy may improve both symptoms and pulmonary function. Noninvasive ventilation (NIV) provides ventilatory support in patients with chronic hypercapneic respiratory failure. In conclusion, we share a presentation of SLS with chronic hypercapneic respiratory failure to raise awareness of potential treatment with MMF and systemic steroids. (Table Presented).