Abstract: This article reports the diagnosis and treatment of a rare case involving a patient with advanced AIDS who developed disseminated cryptococcosis complicated by central nervous system (CNS) injury caused by cat-scratch disease (CSD) and tuberculosis. A 49-year-old female patient was initially admitted due to recurrent headache and fever. Laboratory tests revealed a CD4⁺T-lymphocyte count of 19 cells/μl and a positive HIV confirmatory test. Combined with positive cryptococcal culture in cerebrospinal fluid (CSF) and chest CT findings, she was diagnosed with AIDS complicated by disseminated cryptococcosis (including cryptococcal meningitis and pulmonary cryptococcosis). Her condition improved after anti-cryptococcal therapy, and antiretroviral therapy (ART) was subsequently initiated. Due to irregular secondary prophylaxis with fluconazole, the patient experienced a relapse of cryptococcal meningitis, which stabilized after re-treatment. During standard ART and fluconazole secondary prophylaxis, the patient again developed headache and fever, accompanied by new intracranial lesions. Metagenomic next-generation sequencing (mNGS) of CSF detected sequences of Bartonella henselae. Based on this result and a history of multiple cat scratches, a diagnosis of CNS involvement of CSD was made. Treatment with rifampin combined with doxycycline led to symptomatic relief. However, during treatment, the patient’s condition recurred, presenting with meningeal irritation signs, progressively elevated CSF protein levels, and new intracranial lesions. Subsequent mNGS of bronchoalveolar lavage fluid detected Mycobacterium tuberculosis sequences. In accordance with the patient’s clinical manifestations, CSF biochemical characteristics, and international diagnostic criteria and clinical scoring systems for tuberculous meningitis, a clinical diagnosis of tuberculous meningitis was established. The patient showed significant improvement and normalization of CSF parameters after combined anti-tuberculosis therapy with isoniazid, rifampin, ethambutol, pyrazinamide, and levofloxacin, and follow-up indicated a favorable prognosis. This case highlights the complexity and overlapping nature of CNS infections in patients with advanced AIDS. It suggests that when clinical manifestations are inconsistent with a single infection or treatment response is suboptimal, clinicians should move beyond a “single-etiology” mindset. By integrating epidemiological history, multi-site imaging features, and molecular diagnostic techniques, a high suspicion of mixed infections is essential to achieve comprehensive diagnosis and precise treatment.

Key words: Acquired immune deficiency syndrome, Disseminated cryptococcosis, Cryptococcal meningitis, Pulmonary cryptococcosis, Cat scratch disease central nervous system lesions, Bartonella henselae, Tuberculous meningitis, Pulmonary tuberculosis