Episode 42 of "House"
s02e20 Euphoria (1)

A police officer is admitted in critical condition with a gunshot wound to the head and symptoms that include unexplained giddiness. With no explanation for the odd symptoms, House dispatches Dr. Foreman to the officer's apartment to see if he can gather any clues or possible causes. As the officer's case worsens, Foreman begins to exhibit the same early symptoms and is put in isolation with the patient until House and the team can make a diagnosis. The police officer's condition continues to deteriorate and Forman is forced to watch up-close as the officer descends into unbearable and unmanageable pain. The team races to find the cause of the illness before Foreman's condition takes the same deadly path.