A 56-year-old man presented with sudden-onset abdominal pain and lightheadedness. He had a history of hypertension, which was well-controlled, and of mechanical mitral valve repair for nonrheumatic mitral...
A 14-year-old boy presented with a 2-week history of diarrhea with bright red rectal bleeding. He had had intermittent diarrhea with bleeding for more than 2 years.
