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Thanks for uploading the full image set (attachment removed to protect the patient's identity). I have evaluated them completely and summarise that at present, you have right-sided maxillary sinusitis, left maxillary polyp, and hyperpneumatization of paranasal sinuses. Beginning with hyperpneumatization, it is actually a variant of the normal development process, where the formation of air cells extends further than usual. In your case, there is pneumatization extends into the petrous apices on both sides, the root of the pterygoid process on the left side, as well as into the occipital clivus. Hyperpneumatisation is not a disease by itself, but it can predispose to sinus diseases like sinusitis (or, in some cases, cancer). However, at present, you just got sinusitis, which is seen as a fluid collection in the right maxillary sinus. Other than that, there is a small polyp at the left maxillary opening, which may block the opening and produce headaches also. I do not think any of these findings are related to COVID -19, but perhaps the headache and nasal blockage are aggravated during COVID infection (but not that COVID has produced the polyp or the sinusitis). So, at this stage, I think you can follow the advice of your GP or ENT specialist regarding the management of the sinusitis and the polyp.
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