Inflammation or physical damage to the phrenic nerve may cause elevation of a diaphragm. The phrenic nerve does not travel near the injection site, so it is unlikely to have been traumatized by the cortisone injection. It is more likely that the injection caused a collapsed lung called a pneumothorax. This should have been noticeable on the chest x-ray. A collapsed lung, especially the lower lobe, can cause an elevated diaphragm.
Since the fever was present before the injection was given this excludes the injection as a cause. The fever suggests an inflammatory problem or infection, possibly a viral infection. Phrenic nerve failure due to a viral infection may spontaneously resolve.
The first step is to determine if the left side of the diaphragm moves. If it does the CT scan may show some lung collapse.
This is a complex situation. You should request consultation by a pulmonary specialist.
I thought you might be curious to know the results of the CT scan. It revealed a very large (16 cm), probably fluid-filled, cyst, possibly connected to the spleen. We saw a surgeon today who thinks my son's 2-week fever has been caused by pneumonia. The surgeon sees no urgency in resolving these issues as the risk of hemorrhage is 1%. He said many people are walking around with these cysts without knowing it. They are usually caused from a blow. In my son's case, while on a hike through the mountains, he slipped on a large, wet rock and fell against it.
This particular surgeon has suggested doing surgery in about two weeks. However, since my son is very anxious to feel better and he is now experiencing shortness of breath with exertion, we will be finding another surgeon.
I'm so glad to have found this website and will be making a donation to help ensure it's continuance.
Thanks again.