Final answer:
The indication that Greg should be hospitalized for his pneumonia is difficulty breathing, as it suggests a severe condition that requires immediate medical attention.
Step-by-step explanation:
A 67-year-old man named Greg has been diagnosed with pneumonia. Of the symptoms listed, the indication that he should be hospitalized is difficulty breathing. While fever, cough, and mild fatigue are common symptoms of pneumonia, difficulty breathing suggests that Greg may have severe pneumonia or his lung function is compromised, which requires immediate medical attention and potentially inpatient care.
In older adults, especially those potentially with comorbid conditions, pneumonia can lead to serious complications, which justifies hospital admission for close monitoring and treatment. As in the cases described above, chest radiography and other diagnostic tests are typically used to assess the severity of the pneumonia, which in turn can help in making the decision whether to admit a patient to the hospital or not.