Clinical analysis of 16 cases of pulmonary cryptococcosis in patients with normal immune function

BACKGROUND: Pulmonary cryptococcosis (PC) is an invasive pulmonary fungal disease caused by Cryptococcus neoformans or Cryptococcus gattii. Cryptococcus is the opportunistic pathogen. Immune damage and chronic consumptive diseases are the high risk. The prevalence of cryptococcus infection is 5% to 10% in individuals with weakened immune function. In recent years, with the application of glucocorticoids, antitumor drugs, and broad-spectrum antibiotics, the prevalence of cryptococcal infection has increased yearly. Cryptococcus infection can also occur in normal people without underlying diseases. One in every 100,000 individuals with normal immune function is also affected, but these cases are often misdiagnosed due to inadequate understanding and low awareness of PC in individuals with normal immune function. In this study, we investigated the clinical characteristics of PC in patients with normal immune function to improve the diagnosis and treatment of these cases. METHODS: We retrospectively analyzed the clinical, imaging and pathological data of 16 patients with pulmonary cryptococcosis treated at Beijing Shijitan Hospital between 2010 and 2017. RESULTS: Of the 16 patients with disseminated cryptococcosis, 6 were men, and 10 were women; their ages were 35 to 76 years (median: 53 years). Initial symptoms were cough, sputum, chest pain, and fever. Thirteen patients had a history of chronic disease or tumor, including diabetes and bronchial asthma (n=2), simple hypertension (n=2), chronic bronchitis (n=2), diabetes and hypertension (n=5), previous tuberculosis (n=1), and previous lung cancer surgery (n=1). Chest computed tomography (CT) in these 16 patients showed single or multiple nodules and masses (n=14), lobar consolidation (n=1), and diffuse mixed lesions (n =1). Lung biopsy showed granulomatous lesions in these 16 patients. Cryptococcus neoformans was identified with Grocott's methenamine silver and Grocott's methenamine silver (GMS) stains. Fourteen patients received fluconazole alone; two patients with intracranial infection received fluconazole combined with amphotericin B. Five patients improved significantly, and nine patients improved with significant lesion absorption. CONCLUSIONS: The clinical manifestations of PC are nonspecific in patients with normal immune function. Lung biopsy and cryptococcus antigen tests of cerebrospinal fluid are valuable diagnostic aids. Fluconazole is an effective treatment for disseminated cryptococcal infection.