The condition of ailing DMK patriarch M Karunanidhi has "declined" and keeping his vital organs functioning remains a "challenge", Kauvery Hospital said on Monday, indicating the next 24 hours could be crucial.The next health bulletin is expected within 15 minutes. The 94-year-old five-time Tamil Nadu chief minister was being continuously monitored and treated with active medical support, a press release issued by the hospital said. "His response to the medical interventions over the next 24 hours will determine the prognosis," Executive Director of the Hospital Dr Aravindan Selvaraj said in the terse two-paragraph release. Soon after the news of a decline in Karunanidhi's condition spread, hundreds of his supporters gathered outside the hospital, including a large number of women, some failing to control their tears, others waving at the TV cameras, preparing for an overnight vigil at the facility in downtown Alwarpet.