The 64-year-old woman has had three surgeries on her spine and now has an intestinal infection, lawyer Ferdinand Topacio told reporters.
Arroyo has been hospitalized since Tuesday. Her bid to travel to Spain for medical treatment was blocked Friday when the government of Benigno Aquino III denied her exit status and placed her under arrest on charges of electoral corruption, ABS-CBN News reported.
Sunday morning, about 20 protesters rallied around the hospital where Arroyo is staying, calling for her to be jailed rather than hospitalized, Radio dzBB reported.
Apart from the election fraud charge, Arroya also faces allegations of corruption and graft during her tenure from 2001 to 2010.
Senate President Juan Ponce Enrile criticized the government for side-stepping a Supreme Court decision allowing Arroyo to travel for treatment, China's Xinhua news agency reported.
"Once you weaken the Supreme Court, everybody suffers," he said. "We are inviting a revolt and a civil war here."