Title : Co-infection of Pneumocystis jirovecii and Mycobacterium tuberculosis in a patient with granulomatosis with polyangiitis: A diagnostic and therapeutic challenge
Abstract:
Background: Pneumocystis jirovecii pneumonia (PJP) is a rare but serious opportunistic infection affecting immunocompromised individuals. Although Pneumocystis organisms may colonize healthy lungs, they can cause severe pneumonia in patients with impaired immunity, particularly those with HIV/AIDS or under long-term immunosuppressive therapy. Coinfection with Mycobacterium tuberculosis is uncommon but carries high morbidity and mortality.
Case Description: A 79-year-old woman with granulomatosis with polyangiitis under chronic methylprednisolone and methotrexate presented with fever up to 39 °C, chills, and hypoxemia for 12 hours. Physical examination revealed dyspnea and bibasilar crackles. Laboratory findings showed leukocytosis (WBC 19,360/μL) and mildly elevated CRP (13 mg/L), while blood and urine cultures were negative.
Clinical Hypothesis: Given the acute respiratory deterioration in an immunosuppressed patient, opportunistic or atypical infections were suspected.
Diagnostic Pathway: High-resolution computed tomography (CT) of the chest demonstrated diffuse bilateral ground-glass opacities, patchy consolidations, fibrotic atelectatic areas, and small nodules up to 1 cm. Extensive microbiological workup was performed. Bronchoscopy with bronchoalveolar lavage (BAL) PCR confirmed Pneumocystis jirovecii infection, along with co-existing Mycobacterium tuberculosis.
Discussion and Learning Points: PJP–TB coinfection, though rare, is potentially life-threatening, particularly in immunocompromised patients. Prompt recognition and early treatment initiation are crucial. The patient received intravenous trimethoprim–sulfamethoxazole, dexamethasone, and anti-tubercular therapy (ethambutol, rifampicin, isoniazid) with significant clinical improvement at discharge.
