obstruction of bowels
癥 centers on a blockage or obstruction in the body, specifically in the bowels, causing a hard mass or lump. The idea is something stuck and hardened internally.
癥 combines 疒 (sickness) with 徵, which likely contributes the sound チョウ and may relate to the idea of something accumulating or being summoned, leading to a blockage. The exact historical development is uncertain.
Under the sickness roof 疒, the complex inner part 徵 looks like a tangled, hardened mass. Picture a stubborn lump blocking the bowels, causing illness.
For チョウ, imagine a stubborn blockage named Chou that refuses to move: Chou -> チョウ, and this Chou is the hard obstruction inside the body.