Misdiagnosis of pulmonary paragonimiasis as tuberculosis: A case report

Rationale Pulmonary paragonimiasis and pulmonary tuberculosis exhibit overlapping clinical and imaging manifestations, resulting in frequent misdiagnosis in endemic areas. This case underscores the value of metagenomic next-generation sequencing (mNGS) in correcting such misdiagnoses and emphasizes the importance of managing drug-drug interactions between antituberculosis agents and praziquantel. Patient concerns An 18-year-old female from Yunnan, a paragonimiasis-endemic region, presented with recurrent cough, expectoration, and hemoptysis for 4 years. She was initially diagnosed with pulmonary tuberculosis based on a positive tuberculin pure protein derivative test and chest computed tomography findings but failed to respond to antituberculosis therapy. Diagnoses Pulmonary paragonimiasis (initially misdiagnosed as pulmonary tuberculosis). Interventions In-hospital tuberculosis-related tests (GeneXpert MTB/RIF, sputum/bronchoalveolar lavage fluid culture, bronchoscopic biopsy) were negative. Bronchoalveolar lavage fluid mNGS identified 87 Paragonimus sequences, and Paragonimus antibody enzyme-linked immunosorbent assay was positive. A history of raw crab ingestion was confirmed. Antituberculosis treatment was discontinued for 4 weeks (due to drug interaction), followed by oral praziquantel (1.2 g, 3 times daily for 3 consecutive days). Outcomes Hemoptysis resolved within 15 days of treatment initiation, and peripheral blood parameters returned to normal ranges. Chest computed tomography at 2 months posttreatment showed marked reduction in lesion size, and complete resolution of pulmonary cavities was observed at the 6-month follow-up, with no recurrence of symptoms. Lessons For chronic respiratory symptoms unresponsive to antituberculosis treatment in endemic regions, proactive inquiry of raw freshwater crustacean consumption history and combined use of serology/mNGS can improve diagnostic accuracy. A 4-week washout period after rifampicin discontinuation is critical before praziquantel administration.