There are many causes of left upper lobe lung nodules, the first and most common and easiest to treat is inflammation causing left upper lobe lung nodules. Inflammation can be due to a variety of causes, including viral infections, bacterial infections, and mycoplasma or chlamydia infections, but the most common is a bacterial infection. If the nodule is indeed a bacterial infection, it is often associated with coughing, coughing up sputum and a high fever, and will require intravenous antibiotics. If antibiotic treatment is ineffective, it is best to have a sputum culture and select a sensitive antibiotic for treatment based on the results of the sputum culture and the results of the drug sensitivity test. Another cause may be tuberculosis, which is more common in lung nodules, and patients often have prolonged night sweats, low-grade fever, and hemoptysis. Another possibility is the development of lung tumors, which can also lead to nodules.