CASE REPORT
A 51-year-old female patient with a 10-year history of psoriatic arthritis developed paroxysmal cough and cough with white, sticky sputum after a cold 5 months ago, accompanied by chills, general malaise, chest tightness, shortness of breath, back pain, and hoarseness after exercise. She did not improve after cold treatment. Two months later, shortness of breath after activity and speech worsened, and there was scattered erythema on the neck, some of which merged into a piece, rough skin on the radial side of the right index finger, the distal end of the hands, and white skin after cold; a chest CT was performed at an external hospital. Interstitial infection in the right lobe, lingual segment of the upper lobe of the left lung, and lower lobes of both lungs was observed, and electronic bronchoscopy showed no abnormalities. Pulmonary function tests revealed moderate restrictive ventilatory dysfunction, small airway dysfunction, and moderate diffusion impairment. Electromyography revealed a trend toward myogenic injury in the proximal muscles of the extremities. Bilateral interstitial pneumonia and connective tissue disease were also considered. To combat the infection, methylprednisolone 40 mg once daily and pirfenidone 200 mg three times daily were used for treatment, and the cough and sputum improved, with no improvement in shortness of breath after exercise, without further deterioration. After four months of activity, chest tightness, shortness of breath, cough, and white sputum appeared. She went to the Department of Respiratory Medicine, West China Hospital, Sichuan University, for examination of anti-Mi-2α, anti-MDA5, and anti-PM Scl antibodies (+-). CT scan of the Chest computed tomography revealed vitreous opacities, patchy shadows, and grid-like shadows in both lung membranes, mostly due to interstitial inflammation in both lungs. Biopsy of the left deltoid muscle dermatomyositis skeletal myopathy could not be excluded, followed by methylprednisolone modulation of immunity and no significant relief of symptoms after anti-infection therapy. We considered that our department should check for positive anti-MDA5 antibodies to diagnose DM and to check the finger pulse. Oxygen 89% (no oxygen inhalation), dry and wet rales could be heard, a small amount scattered in the lower lungs, veclro rales could be heard in the bases of both lungs, chest CT showed chronic interstitial changes in both lungs; mixed type in the lower lobes of both lungs Possibility of infection, fungus, procalcitonin(Figure 1) , C-reactive protein, erythrocyte sedimentation rate, muscle enzyme spectrum, electrolytes, thyroid function, tumor markers were normal, excluding other autoimmune diseases and tumors, sputum culture was Lewy persistent bacillus infection, antibiotic anti-infective treatment and methylprednisolone 40 mg qd (reduced by 4 mg per week), cyclosporine 25 mg bid, pirfenidone 200 mg tid treatment, cough, sputum, chest tightness, shortness of breath, muscle pain significantly improved, no skin damage.
After 12 weeks of treatment, the patient visited Peking Union Medical College Hospital and was found to be anti-MDA5 positive. The patient was treated with methylprednisolone (12 mg qd), tacrolimus (2 mg qd), cyclophosphamide (50 mg qd), and pirfenidone (200 mg). No rash was observed after treatment. Muscle pain was present, but chest tightness, shortness of breath, cough, and sputum production were observed.
After 36 weeks of treatment, considering the toxic side effects of cyclophosphamide, after excluding infection, tumor, tuberculosis, and hepatitis, we adjusted the treatment plan to methylprednisolone 6 mg qd, tacrolimus 2 mg qd, tofacitinib 5 mg bid, and pirfenidone 200 mg tid. Chest tightness and shortness of breath, cough, and expectoration continued to be relieved, and hormone levels were successfully reduced after 52 weeks of treatment. Tacrolimus Capsules 1 mg qd remained in remission and underwent multiple follow-ups; the anti-MDA5 antibody was positive many times using the Cytometric Bead Array (CBA) detection method.
At the 132 weeks of follow-up, we comprehensively evaluated the patient’s condition. Pulse oxygen was 95% (without oxygenation), and pulmonary function was normal. After repeated checks, the anti-MDA5 antibody was negative, and the symptoms continued to be relieved. First, we continued to administer tacrolimus division 1 mg qd, tofacitinib 5 mg bid, and pirfenidone 200 mg qd maintenance therapy (Figure 2) . It is worth noting that the patient’s muscle enzyme, immunoglobulin, C-reactive protein, and erythrocyte sedimentation rates were normal from the onset to the 132-week follow-up(Figure 3) .