A case of severe psittacosis in a hemodialysis patient-the critical role of detailed medical history and next-generation sequencing.

An 80-year-old male patient on maintenance hemodialysis was admitted with "high fever and cough." Pulmonary imaging suggested pneumonia, but his condition deteriorated rapidly despite empirical broad-spectrum antimicrobial therapy (covering bacteria, atypical pathogens, and fungi), progressing to respiratory failure and delirium. He was transferred to the intensive care unit for continuous renal replacement therapy. Routine microbiological tests (blood culture, sputum culture, respiratory pathogen PCR) were all negative. Detailed history revealed that the patient had kept a parrot for over a month prior to illness onset. Metagenomic next-generation sequencing of blood and sputum specimens detected abundant Chlamydia psittaci sequences. Following confirmation, treatment was adjusted to oral minocycline combined with intravenous azithromycin. The patient's temperature gradually normalized, neuropsychiatric symptoms resolved, and pulmonary imaging showed marked improvement, ultimately leading to successful discharge. This case highlights the importance of considering zoonotic pathogens in immunocompromised patients with refractory pneumonia. Detailed history-taking and metagenomic next-generation sequencing (mNGS) technology are crucial for early diagnosis. Early use of mNGS should be strongly considered in immunocompromised patients with severe pneumonia unresponsive to empiric therapy and negative routine workup, particularly when epidemiological clues such as bird exposure are present.