Pneumonia caused by co-infection with Mycobacterium tuberculosis and Pneumocystis jirovecii leading to acute respiratory distress syndrome in an HIV-negative immunocompromised patient: a case report and literature review

Pulmonary tuberculosis (PTB) and Pneumocystis jirovecii pneumonia (PJP) often occur in immunosuppressed populations, particularly in individuals with human immunodeficiency virus (HIV) infection. However, co-infection with these two pathogens resulting in acute respiratory distress syndrome (ARDS) has been less frequently reported, especially in HIV-negative patients. We report the case of a 68-year-old immunosuppressed male patient with pneumonia caused by co-infection with Mycobacterium tuberculosis and Pneumocystis jirovecii, leading to ARDS, who was successfully treated. Following a definitive diagnosis of pemphigus vulgaris and 3 months of glucocorticoid and immunosuppressive therapy, the patient had a sudden onset of fever and dyspnea. He was admitted to the respiratory department of a general hospital with a diagnosis of severe community-acquired pneumonia. Metagenomic next-generation sequencing of bronchoalveolar lavage fluid detected the presence of M.tuberculosis and P. jirovecii. Owing to the suspected contagious nature of tuberculosis, he was transferred to the tuberculosis department of our hospital. The patient developed severe respiratory distress; chest computed tomography (CT) revealed cavitary lesions and progressive pulmonary exudative changes, and arterial blood gas analysis demonstrated hypoxic respiratory failure. Because of limited respiratory support resources in the tuberculosis department, the patient was then transferred to the Respiratory Intensive Care Unit for endotracheal intubation and invasive mechanical ventilation. The patient received high positive end-expiratory pressure respiratory support therapy and restrictive fluid management strategies. Clindamycin combined with caspofungin was administered for PJP because of a suspected sulfonamide allergy, while standard first-line anti-tuberculosis therapy was initiated concurrently. The patient showed progressive clinical improvement and was successfully extubated on day 7 after intubation. At one-month follow-up, he had recovered well, and chest CT demonstrated substantial resolution of pulmonary lesions. The successful management of this patient was attributed to timely etiological diagnosis, targeted anti-infective therapy, effective supportive respiratory care, and fluid management. This case highlights the importance of heightened vigilance and prompt, comprehensive treatment in immunosuppressed patients with severe pneumonia, particularly in non-HIV individuals.