Also known as: Heart failure
Ryan developed cardiomyopathy secondary to dialysis, leading to heart failure and complete kidney shutdown. This drives the main medical plot involving his need for a kidney transplant from his mentally disabled brother Kevin.
Also known as: Kidney failure
Ryan's kidneys have completely shut down, requiring him to be placed on the transplant waiting list. He receives a kidney from his brother Kevin, but ultimately the transplanted kidney hemorrhages and is rejected by his body, leading to his death.
Also known as: Mental retardation
Kevin has significant intellectual disability that raises ethical concerns about his ability to consent to donating a kidney to his brother. His condition is central to the moral dilemma of whether he truly understands the risks and whether his brother is exploiting him.
Also known as: Bleeding after delivery
Sharon, who wants to be a surrogate for the Walkers, has significant uterine scarring from instrumentation after a previous postpartum hemorrhage. Addison must perform a hysteroscopy to resect the scar tissue before Sharon can carry a pregnancy.
Also known as: Lupus
Kendra's history with lupus prevents her from safely carrying a pregnancy, necessitating the use of a surrogate to have another child after losing their son.
Also known as: Heart transplant rejection
After receiving his brother's kidney, Ryan's body rejects the transplanted organ, causing it to hemorrhage into his abdomen. This rejection is fatal and represents the tragic conclusion of the transplant storyline.
Also known as: GSW to chest
Referenced as having recently occurred - Derek (Amelia's brother) was shot in the chest by a crazed gunman. This is a continuing arc that affects Amelia's emotional state and prompts her to reach out to her brother.