Monroe was a clinic patient in the Season 8 episode Parents. He is the husband of Sandy. He was portrayed by actor John Scurti.
Monroe came to the clinic demanding to be tested for diabetes. After his tests were completed, he was seen by Gregory House. Dr. House reviewed the test results and did a quick examination and found no indication that Monroe had diabetes. Monroe insisted he did - he was gaining weight, felt fatigue and was sluggish. Dr. House pointed out that none of those are symptoms of diabetes (diabetics lose large amounts of weight) and that sluggishness and fatigue are, in fact, the same symptom. He also said he would love to give him insulin like he wanted, but it would dangerously lower his blood sugar, resulting in coma and death. He told Monroe he could leave. Monroe demanded more tests and Dr. House seemed to agree. However, after he left the examination room, he told one of the nurses that Monroe was the subject of a sleep study and should not be disturbed for eight hours.
Later, Monroe came back tot he clinic with a urine sample, demanding it be tested. Dr. House took the sample, examined it carefully, opened it, sniffed it, and drank some of it. He pronounced it was apple juice - a trick that patient's use to boost their blood sugar levels. Monroe complained that his ankles were swelling. Dr. House initially thought that Monroe was pulling an insurance scam by submitting someone else's urine, but finally realized that Monroe was a hypochondriac. Monroe insisted that both his father and older brother had developed diabetes at the same age and that he had to stay ahead of it.
Later still, Monroe's wife Sandy came to Dr. House. She told him that Monroe was insisting on only eating diabetic meals. She asked if Dr. House could write a fake prescription so she could inject him with water and then prove to him that he was really fine. Dr. House reminded her that she didn't need help for a fake prescription.
However, while treating another patient, Dr. House realized that there could be another cause of Monroe's swollen ankles that was related to his diet. He called Monroe and Sandy back in. After revealing that the wife's shots were merely a placebo, he asked if Monroe ate a lot of bok choy on his diabetic diet. His wife said he ate about a pound a day. Dr. House then asked why Monroe didn't tell him about his bradycardia. Monroe denied having a slow heart rate, but when Dr. House tested it, it was a very low 52 bpm Monroe was astounded. Dr. House told him that the bok choy contained chemicals that suppressed the function of his thyroid resulting in hypothyroidism. He told him he would be fine if he stopped eating bok choy, but reminded him that if he didn't watch his obesity he could still get diabetes.