Also known as: Memory loss
House has lost approximately 4 hours of memory following a bus crash. The episode centers on his attempts to recover these memories through hypnosis, sensory triggers, and drugs to identify a patient he believes is dying.
Also known as: Head laceration
House has a longitudinal fracture of the temporal bone extending to his ear canal, with edema and localized swelling in the temporal lobe controlling short-term memory. He experiences bleeding from the ear, vomiting, and progressive neurological deterioration throughout the episode.
Also known as: Sudden paralysis
The bus driver experiences sudden onset paralysis of his legs following the crash. This symptom drives House's investigation as he works through multiple differential diagnoses.
Also known as: Air bubbles in blood vessels
The bus driver develops an air embolism from recent dental surgery that travels through his system causing paralysis, liver failure, jaundice, and pulmonary obstruction. House eventually realizes the crash dislodged the bubble rather than the bubble causing the crash.
Also known as: Kidney failure
Amber (identified as Jane Doe #2) was on the bus with House and sustained kidney damage in the crash. House realizes at the episode's end that she is the dying patient he's been searching for.
Also known as: Brain infection
House suspects a bus crash victim with fever and stiff neck has meningitis and orders quarantine of the entire ER. The diagnosis is ultimately ruled out but drives the quarantine subplot.
Also known as: Liver failure
The bus driver develops liver failure with jaundice and low albumin as the air embolism affects his hepatic system. This leads the team through various differential diagnoses.