Acute vs Chronic. The difference between acute and chronic when used for diseases is that acute means extremely severe pain, brief and dangerous disease whereas chronic refers to a medical condition that lasts over a long period.Chronic also means something always present and recurring or something habitual.cute vs Chronic. The difference between acute and chronic when used for diseases is that acute means extremely severe pain, brief and dangerous disease whereas chronic refers to a medical condition that lasts over a long period. Chronic also means something always present and recurring or something habitual.