House Training
"House Training" is the 20th episode of the third season of House and the 66th episode overall.
Plot
A young female scam artist named Lupe (Monique Gabriela Curnen) collapses while participating (possibly acting as a shill) in a Three-Card Monte scam on the street. She suffers from a lack of blood to the brain which temporarily paralyzed her ability to make decisions or exercise free will ("aboulia," says Foreman, as "part of a […] transient ischemic attack"). Based on her background, Foreman immediately suspects Lupe's condition stems from drug abuse, while Chase looks for other possibilities, such as toxins in her apartment. Lupe senses Foreman's disdain for the decisions she's made in her life, and Foreman grapples with his own humble past when his parents come to visit him.
When Lupe's symptoms worsen and her organs begin to shut down, Foreman and the team suspect autoimmune disease to be the culprit. When treatment does not work (symptoms worsen), the team thinks it must be cancer. Foreman presses for a full-body radiation treatment. However, severe pain after the radiation leads the team to the final, correct diagnosis: an infection. The radiation treatment has destroyed Lupe's immune system and there is nothing anybody can do to save her. Foreman tells her the news and helps her cope with it.