Also known as: MS
Dr. Bell is diagnosed with multiple sclerosis, experiencing numbness in his hands, loss of dexterity, and optic neuritis. This diagnosis drives a major subplot as he decides to leave surgery and Chastain permanently, though Kit convinces him to fight the disease and stay.
Also known as: Heart transplant rejection
Hannah, a heart transplant recipient who received Nic's heart, presents with heart failure and apparent rejection. This is the central medical case of the episode and emotionally significant as it involves Conrad's deceased wife's donated heart.
Also known as: Brain AV fistula
The root cause of Hannah's heart failure symptoms is discovered to be a dural arteriovenous fistula causing neurological symptoms including memory loss that made her forget to take her immunosuppressants. Billie performs surgery to repair it.
Also known as: Stage 4 lung cancer
AJ's mother Carol's lung cancer is progressing with new liver metastases. AJ tries to get her into Devon's clinical trial but she doesn't meet criteria. Instead, they transition to palliative care.
Also known as: Heart failure from brain injury
Hannah develops cardiogenic shock from her worsening heart failure, requiring emergency placement of an intra-aortic balloon pump in the cath lab to stabilize her.
Also known as: Brain bleed
Hannah develops a small brain bleed, likely caused by blood thinners needed for her balloon pump, which worsens during surgery requiring urgent intervention.
Also known as: Air bubbles in blood vessels
During Hannah's brain surgery to repair the dural fistula, an air embolism develops that threatens to reach her heart, requiring immediate intervention by AJ to aspirate it.
Also known as: Vision loss from immune response
Bell experiences an episode of optic neuritis (eye pain and vision changes) as a manifestation of his MS, which he views as evidence of rapid disease progression.