A friend contracted bacterial pneumonia and was hospitalized last month. She is still running a temperature of 102-103 degrees. She is sedated, and they recently did a CT scan of her head because they cannot find what is causing this infection. They operated on her upper back to remove pus from her lungs. Her condition has not improved. She is 50 years old, has diabetes and high blood pressure and is quite obese. I cannot understand why it is so difficult for the doctors to find the source of her infection.

B.

There are several reasons your friend may be having a fever despite a long course of antibiotics. Usually, pneumonia responds well to antibiotics, with temperature returning to normal in just a few days. Sometimes, the patient comes to medical attention too late and, despite aggressive treatment, succumbs to the infection. The case of your friend is different. It sounds as if she initially responded to antibiotics but then stopped improving. When this occurs, one must suspect a secondary infection.

Your friend had a one type of secondary infection, pleural empyema. That is when the pneumonia spreads to the pleura, the tissue surrounding the lungs. Pus collects between the lungs and pleura, causing fever and chest pain. Unless the pus is drained, the bacteria can spread, resulting in blood infection and even death. You stated that the pus was drained from your friend's chest. However, one common problem is inadequate drainage. I have seen many cases in which a pleural empyema is only partly drained, and the patient remains feverish, becoming increasingly more ill. This would be the first thing I would look for. A CT scan of the chest would show if there was any undrained pus.

There are also other possibilities. The infection could have already spread somewhere else in the body. Any bacterial infection can rarely spread to the brain, the bones, the liver and other sites. If these infections are suspected, various scans could diagnose the problem.

Another possibility to consider is a drug fever. Any medication (and antibiotics are common culprits) can cause a fever. This typically occurs several days after the drug is started. There may be clues to this diagnosis in the form of skin rash, liver-function test abnormalities and a excess of white blood cells called eosinophils. The only way to prove the diagnosis is to stop the offending drug and see what happens. Usually a drug fever resolves in just a few days after the drug has been discontinued.

I think that the most likely situation is that there has been inadequate drainage of the pleural empyema. I would do a CT scan of the chest. If there are several areas of undrained pus, she may need surgery to cure the infection. Otherwise, drainage can be attempted without surgery by an interventional radiologist. The radiologist locates the area to be drained using a CT scan, making it easier to get a needle into the fluid.