Final answer:
The student is likely showing symptoms of pneumonia, and the next best step would be to get a chest X-ray to confirm the diagnosis and evaluate the extent of lung involvement.
Step-by-step explanation:
The symptoms described in the question, including a productive cough with yellow-green sputum, runny nose, and fever, along with physical examination findings of decreased breath sounds and crackles in the lower left lung lobe (LLL), suggest a diagnosis of pneumonia. The high white blood cell count (WBC) of 16,000 also indicates an infection. Pneumonia is an infection that causes inflammation and accumulation of fluid in the air sacs of the lungs and can be caused by various pathogens.
The next best step would be to obtain a chest X-ray to confirm the diagnosis and evaluate the extent of lung involvement. A chest X-ray can show consolidation or infiltrates in the affected lung lobe. The X-ray findings, along with the clinical presentation and other tests such as sputum culture, will help determine the appropriate treatment for the specific pathogen causing the pneumonia.