House Season 1 Episode 3: Occam's Razor
Full Recap
Brandon, a 22-year old male, passed out after having sex with his fiancée. He had been complaining about a cough and a rash beforehand. Now he is suffering severe abdominal pain, nausea, fever and low blood pressure.
A quick scan and exam reveal nothing, so House and team look for alternate answers. Dr. Cameron points out that no condition accounts for this many symptoms. House realizes they need to control the patient's blood pressure first, and they run a core stem test and an EKG test among others.
The tests don't reveal much, but Dr. Foreman sees a result that signifies that the antibiotic treatment is shutting down Brandon's kidneys. Foreman theorizes that Brandon has a heart infection, not a stomach infection, which explains each symptom. Yet this is a 10 million to 1 shot. House, looking at a list of Brandon's symptoms, offers that two possible conditions combined -- a sinus infection and hypothyroidism -- account for all of Brandon's symptoms. And that's only a million to 1 shot. Since there's no time to wait for test results, he wants to start treating the sinus and thyroid immediately.
Foreman checks in on Brandon. The patient is feeling better but is still stuck with a cough. Foreman reports that Brandon tested negative for hypothyroidism. He insists that it can't be two illnesses and House's treatment regimen will only harm Brandon's liver. It could even kill him. House offers Foreman a $50 bet. If Brandon's white blood count goes up, Foreman is correct in presuming that he's actually fighting off an infection.
Brandon's white blood cell count drops. Both of their hypotheses were wrong. If Brandon gets so much as a cold, his body won't be able to fight it off and he will die. House has a revelation. He asks Dr. Wilson which of Brandon's symptoms came first. It was the coughing.
After a little research, House knows the answer. Brandon had visited a doctor for his cough and his prescription for cough medicine was accidentally filled with gout medicine. That medicine stops mytosis, the process in which cells divide and replace dead cells. This is not occurring, which explains each of the symptoms. But Dr. Cameron points out that Brandon did improve, but then worsen after checking into the hospital and stopping the gout medicine.
House meets with Brandon's parents and demands to know who prescribed the cough medicine which led to their son's deterioration. His mother gave it to him. She produces the pill bottle, which validates House's thinking. Chase and Brandon's mother visit the pharmacy. Brandon was indeed taking cough medicine and not gout medicine, disproving House's theory. House is incredibly annoyed that his elegant, thoughtful hypothesis wasn't proven right.
Dr. Wilson suggests exploratory surgery to find out what's in Brandon's blood. During the prep for surgery, Brandon's heart stops beating and the doctors shock him back to life. Cameron tells House about the surgery emergency and also mentions that Brandon is experiencing pain in his fingers. House has another revelation. He barges into Brandon's clean room and announces his diagnosis of colchicine poisoning. The order of Brandon's symptoms fits perfectly, which means that Brandon is doing drugs. Brandon admits that he's done ecstasy twice, which House notes is cut with colchicine. A quick fix and Brandon will be just fine.
House is still not ready to give up his theory about the wrong cough medicine and is looking through all the bottles in the hospital pharmacy. In the meantime, though Brandon is improving, his cough still persists. When Cameron gives him his cough pills he notices that they don't have a letter on them as the earlier pills had. At the same time we see a very relieved House who has plain cough pills in one hand and the pills with the letter in the other.

Not written by me. Credit to Tv.com