noun
acute phase; acute stage
Medical term referring to the early, severe stage of a disease or condition, often contrasted with 慢性期 (chronic phase).
See also: 慢性期
急性期の治療が終わったら、リハビリを始めます。
After the acute phase treatment is finished, we will start rehabilitation.
この病気は急性期を過ぎると症状が落ち着くことが多い。
With this illness, symptoms often settle down after the acute stage passes.