Whether ground glass lung nodule 4.5mm is serious or not needs to be judged according to the nature of the nodule, if it is benign nodule, there is no need to worry too much, malignant nodule is more serious. Ground glass lung nodule 4.5mm belongs to a relatively small lung nodule, the possibility of malignant nodule is low, if the patient has no other clinical symptoms for the time being, the nodule shape is regular, you can follow up and observe, regularly review whether the nodule is enlarged. Ground glass lung nodules are mainly seen in pneumonia, tuberculosis, lung tumors and other diseases, the severity of different diseases is different, and the treatment measures are also different. If the lung nodule is caused by inflammation, there is no need to worry too much, and anti-infection treatment can be carried out against the pathogen. If the nodule is malignant, attention should be paid to it, and surgery should be performed as soon as possible if necessary. It is recommended to go to a regular hospital for timely treatment of ground-glass lung nodules, so as to avoid delaying the condition.