Also known as: Thymus tumor
Professional cyclist Jeff Forster is ultimately diagnosed with a thymoma (tumor on the thymus gland), which is the root cause of his respiratory distress and other symptoms. This diagnosis is the episode's medical mystery resolution.
Also known as: PRCA
Jeff's chronic PRCA (causing severe anemia with red blood cell count dropping to 16%) was unknowingly being treated by his blood doping regimen. When he stopped doping for the charity ride, the condition became symptomatic. PRCA is revealed to be caused by the thymoma.
Also known as: Myasthenia
Autoimmune disease causing Jeff's progressive muscle weakness, fatigue, respiratory distress, difficulty swallowing, and drooling. Associated with his thymoma. His hyperbaric chamber use was unknowingly treating this condition.
Also known as: Air bubbles in blood vessels
Initially believed to be causing Jeff's respiratory distress from his frequent self-injections. Chase performs an embolectomy to remove it, but this turns out to be a red herring rather than the primary diagnosis.
Brief clinic patient (flight attendant) presenting with severe diarrhea after quitting smoking, diagnosed as sorbitol poisoning from excessive sugarless gum chewing used as oral fixation replacement.