"Mirror Mirror" is the fifth episode of the fourth season of House and the seventy-fifth episode overall. It aired on October 30, 2007.
Plot
Medicine
House's team gets a patient (Frank Whaley) with breathing problems with no apparent cause. He was just robbed and does not have I.D. on him, and they do not have his past medical records. Foreman suggests it might be a result of a vocal cord spasm, and they give him methacholine which would worsen it and thus provide a diagnosis. The patient complains of additional symptoms, and Foreman determines that he is faking them. His alleged symptoms are the same as those of other patients, and the name he gave them was the same as the paramedic. Foreman thinks he might have Munchausens, but House thinks it might be a rare form of anterograde amnesia known as Giovannini mirror syndrome (Named After Giovannina Conchiglia) that causes a patient to mimic those around him. House suggests that they try to convince the patient that he is a doctor, since a mirror syndrome patient would be convinced, but a Munchausens patient would not. They go to one of Wilson's surgeries, and the patient acts like a doctor. Specifically, he acts like Wilson. Wilson later notes that mirror patients always mirror the most dominant person in the room, which means that Wilson was more dominant than House. House explains that as a consequence of the fact that Wilson was in charge of the surgery.
House notices that the patient's blood thickens dangerously when his body temperature drops (cold agglutinin disease), something that cannot be faked. They look for an infection that could have caused it. The patient has his car keys on him, so House sends Cole to look for the patient's car, and Thirteen volunteers to go along. Brennan suggests that the patient might have a fungus, but the cure does not work. They put the patient in a hot tub to keep him warm. House suggests they get a medical history by checking his blood for antibodies. The test reveals that he has had histoplasmosis, a disease common in Ohio, but also coccidioidomycosis, residing in southwestern US, and Chagas disease, pointing to Central America. The patient has heart problems, so Foreman suggests they biopsy the heart. Brennan says that will kill him since the patient just had a heart attack. Foreman then makes a House-like statement, sarcastically saying "We biopsy his toe instead". House tells everyone to biopsy the patient's heart, which reveals nothing.
Cole and Thirteen find the patient's car, which allows them to determine his name, his hometown, and that he carries vaporub. The patient earlier said he liked hot tubs in the presence of Kutner, who later states he hates hot tubs. This evidence shows the patient was capable of thinking for himself, so House pretends to be the patient, so that when the patient mirrored him, he would say more about himself. The patient says he was on the road a lot, and he used the vaporub to block out the smell of dung. House infers that the patient sells farm equipment, and is around pigs a lot, and correctly diagnoses him with eperythrozoon, an infection that occurs in pigs.
Chase takes bets on who will be fired at the end of the case. House does not fire any of the candidates, so Chase wins all the bets. House confirms Foreman's suspicion that he was in the gambling with Chase on the bets and received 50% of the money. As they walk away, "We're Going to Be Friends" by The White Stripes plays, suggesting House and Foreman might begin to get along better, perhaps because they are so similar.
Foreman, Cuddy, and House
House didn't want Cuddy to rehire Foreman, and they get into a power struggle. To waste Cuddy's time, House tells the people in the cafeteria that the food was spoiled, and they should all go to the clinic. Then he orders unnecessary, expensive tests for the uninsured clinic patients. In retaliation, Cuddy replaces House's Vicodin with laxatives. House responds, "I know when my Vicodin isn't Vicodin. Do you know when your birth control pills aren't birth control pills?"
House realizes that no one is going to back down. (His exact quotation is "No one's going to be happy here... and Cuddy's going to end up pregnant.") So House tells Foreman he got him a job somewhere else. At first, Foreman claimed that he was miserable working with House again. But when the patient was mirroring Foreman, he said that he liked being there. Foreman realized he did like being back, and he says he doesn't want House to get him a job somewhere else.