Responsa zu Jeschijahu 51:14

They responded to the first question: "Lift your hands to the sacred!" (Psalms 134:2) Namely, wash your hands whenever you want to speak sacred words or study Torah. "And bless God!" (ibid.) - with the blessing instituted for washing hands. As for the second question, they responded: Do you not know that four need to give thanks (Berachot 54b:12), and this includes one who was sick. And none are more sick than such a person [who relieves themself], as it says (Isaiah 51:14): "Quickly the crouching one is freed."²cf. Rashi on Isaiah 51:14