Q. Does one have to wash his hands again with a beracha after going to the bathroom in the middle of a seudah?

A. Mishna Berura (164: 12) quotes different opinions whether one should recite a brocho after washing hands (with a keli as in the beginning of the meal) when attending one’s needs during a seuda. He rules that after a bowel movement, soiling one’s hands or abandoning the seuda, a brocho should be recited. However, after only urinating or just touching covered areas of one’s body, netilas yadaim is required but without a brocho. Chaye Odom’s (40: 14) opinion is that washing with a brocho is necessary when touching urine.

Horav Shlomo Miller Shlit’a pointed out that a brocho should only be recited if one is planning to eat an eggs size of bread when continuing the meal (See Mogen Avrohom 170: 2)

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a