Holiday from Hell - S7.E7

The show's fourth Christmas-themed episode, and the second episode of the series that looks back at three past cases, including: a baby whose brain was infected with Cytomegalovirus in utero (All I Got For Christmas Is Brain Surgery); a woman whose eye is infected with the worm Dirofilaria immitis (A Holiday in the Hospital); and a man who has a surgical sponge left in his colon (also A Holiday in the Hospital).