The goal of this observational study is to explore the correlation between total sialic acid combined with superoxide dismutase and the diagnosis and prognosis of lipid pneumonia in the patient with lipid pneumonia, cough, bacterial and fungal pneumonia, cryptogenic organizing pneumonia, pulmonary alveolar proteinosis, lung mucinous adenocarcinoma and pulmonary edema. The main question it aims to answer is:

Whether superoxide dismutase (SOD) and total sialic acid (TSA) could be used as diagnostic markers to distinguish lipid pneumonia from patient with cough, and bacterial and fungal pneumonia, cryptogenic organizing pneumonia, pulmonary alveolar proteinosis, lung mucinous adenocarcinoma and pulmonary edema, whether SOD and TSA be associated with the prognosis of patients with lipid pneumonia?

Participants will answer online survey questions about their symptoms, changes in oxygen status, and changes in the most recent CT image of the lung for up to 10 years after treatment. We will count participants' baseline data including: gender, age, smoking history, comorbidities, lung function, imaging findings, hormone use or not, ICU treatment, death or not, the type of cause of lipid pneumonia, how it is diagnosed, and their baseline SOD and TSA.

Inclusion Criteria:

1. Age≥ 18 years old;
2. The diagnosis of lipoid pneumonia must be supported by lung biopsy pathological support or positive oil red O or Sudan staining in bronchoalveolar lavage fluid;
3. Patients with bacterial and fungal pneumonia must be supported by etiological evidence;
4. Patients with cryptogenic organizing pneumonia and pulmonary alveolar proteinosis must be supported by lung biopsy pathology;
5. Patients with lung mucinous adenocarcinoma must be supported by lung tissue biopsy;
6. Lung imaging of patients with pulmonary edema must show paving stone signs;

Exclusion Criteria:

1. Age< 18 years old;
2. The patient only has a history of lipid inhalation and no pathology or positive lipoid staining;
3. Co-infection with the corona virus disease 2019 at the onset of illness;
4. Pregnant

This study includes the lipoid pneumonia patients, patients with cough in the upper respiratory tract only, patients with bacterial and fungal pneumonia, patients with cryptogenic organizing pneumonia and pulmonary alveolar proteinosis, patients with lung mucinous adenocarcinoma and patients with pulmonary edema.

All IPD collected throughout the trial, only IPD used in the results publication