I have suffered with chronic sinusitis for 8 years. Jan 2019 I went to the E.R and found out I had pneumonia. O2 was 63. I found out I had iron deficient anemia, low thyroid and left the hospital after a week with an Inogen (oxygen machine). I have been to a lung doctor, hematologist/oncologist, ENTs. They did a bronchoscopy and found gramulomas..sarcoidosis...