Co-Infection with Nocardia Terpene and Pneumocystis Jirovecii in a Patient with Anti-Synthetase Syndrome: A Case Report

Background: Pulmonary infection is a common clinical complication associated with glucocorticoid. There have been no reported cases of mixed infections involving Nocardia and Pneumocystis jirovecii combined with anti-synthetase syndrome (ASS) activity. Methods: This study conducted a retrospective analysis of the clinical data from a patient with active ASS, treated for a pulmonary coinfection. Results: The patient exhibited fever, asthma, and cough as initial symptoms. Chest CT scan revealed multiple infiltration shadows, consolidation shadows, nodules, mass shadows, and internal cavities in both lungs. BALF mNGS detected Nocardia terpene and Pneumocystis jiroveci. Treatment with sulfamethoxazole/trimethoprim and corticosteroids led to an improvement. However, the patient experienced recurrent fever and a new rash with the reduction of the glucocorticoid dosage. Further investigation identified positive anti-Jo-1 and anti-Ro-52 antibodies and myogenic lesions on electromyography, which confirmed the diagnosis of ASS. Following treatment with immunoglobulin, methylprednisolone, and cyclosporine, the patient's condition significantly improved. Conclusion: Immunodeficiency patients are susceptible to opportunistic infections. mNGS is valuable for diagnosis and treatment. Although the image of Nocardia terpene and Pneumocystis jiroveci infections lack specificity, they exhibit distinctive features. Should fever and skin lesions reoccur post-effective anti-infective therapy, it is imperative to explore non-infectious causes and expedite autoantibody testing.