(CNN) "Nobody is taking care of us," said Josefina Alvarez, 62, who had been stuck in a shelter outside of San Juan for nearly two weeks.

She is one of many Puerto Ricans who have been displaced -- and put in grave danger -- in the aftermath of Hurricane Maria.

Alvarez is sick and bedridden. A diabetic with breathing issues, she's getting worse by the day. Now, she might have a life-threatening infection -- and no one can get her to a hospital.

Not even Dr. Astrid Morales.

"She's getting more complicated, with fever and all that, and we have nothing here to give her," said Morales, a local doctor who has been visiting patients at a shelter in Loiza. "Time is really limited."

When CNN arrived at the shelter, an ambulance was there but didn't have enough gasoline to get her to the nearest hospital. On another occasion, a medical team said they didn't have "authorization from their bosses" to get an ambulance to take her, according to Morales.

"We're in the middle of a disaster ... and you're waiting for paperwork?," CNN Chief Medical Correspondent Dr. Sanjay Gupta said.

"The hospitals are closed ... not taking any patients," Morales lamented.

Doctors expected hospitals in Puerto Rico to overflow with patients who were desperately seeking care after the storm. But a week after the storm, many have no long lines at all; waiting rooms are unexpectedly sparse.

Instead, many are in shelters. When some hospitals closed temporarily around the storm, people didn't know where else to get help. Many flocked to shelters where they thought they'd be safe.

This included bedridden people and others who have been too sick or disabled to leave the shelters on their own. But shelters lack the power, medications and supplies to treat people like Alvarez.

And some who didn't evacuate are still stuck in their homes, according to Morales.

"They're trapped," she said.

At any moment

A nearby hospital was supposedly up and running -- the Concilio de Salud Integral de Loiza. But the hospital said it wasn't accepting any patients, Morales said. Meanwhile, Alvarez wasn't getting any better.

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Gupta said some facilities are afraid to accept patients because they don't have enough medications, fuel for generators or clean water; they could be forced to shut their doors at any moment.

On Tuesday, Gupta spoke to a doctor at one clinic that only had six hours of diesel left. By Wednesday, they received fuel, but their water supply was now running low.

There are 51 hospitals considered operational out of the island's 69, according to homeland security adviser Tom Bossert.

For a hospital to be considered open, "that generally focuses first on their ability to provide and sustain emergency power -- whether they have diesel fuel. And that's not necessarily an ideal condition," Bossert said. He added that hospitals must also have the staff and medicines required to see, treat and admit patients.

The reported numbers of open facilities don't seem to match the reality on the ground, according to doctors on the island.

Finally, an answer

Doctors outside of San Juan are frustrated -- bewildered, even. Some basic supplies are already on the island, but a fuel shortage, blocked roads and other challenges have hindered their distribution.

Supplies aren't getting to shelters, and patients aren't getting to the hospital.

"We need to find out where we can send patients," Morales said. "The communications are awful."

Her priority was to get help for Alvarez.

"If we can get in touch with the health secretary, maybe he can tell us where we can send patients, which emergency rooms are open," she said. "Or send us IV antibiotics, and we can deal with it here."

Morales was able to reach the health secretary on a CNN satellite phone. She spoke in Spanish about Alvarez: "There's a patient who has had an abscess for a week and a half."

After a brief conversation, she had an answer: Alvarez could go to Centro Medico in San Juan, one of the largest hospitals in the Caribbean.

But she needed to get there.

"We've been to this Centro Medico. We know what the facilities are like," Gupta told her. "We could take the patient ourselves. I know time is of the essence here."

One of many

"That hurts!" Alvarez moaned as she was moved into a wheelchair, and then into a large black van that was hardly equipped to serve as an ambulance. But it was the only option.

Alvarez lay on her right side, with an abscess on her left. Her husband held her hand from the back seat during the ride to San Juan.

When they finally reached the hospital, she was whisked away on a stretcher and into a tent. By the evening, doctors were planning to perform surgery on her abscess and treat the infection.

She got the care she needs, but Alvarez is just one patient.

"There are probably thousands of patients who are in similar shelters -- no power, no water, no medications, no way out. There are probably thousands more who are still in their homes," Gupta said.

There are over 10,000 people in shelters across Puerto Rico, according to FEMA. Like Alvarez, many are only getting sicker.

"These people are going to need help for quite a while," said Dr. Jim Lapkoff, a chief medical officer with the National Disaster Medical System. Lapkoff is one of the doctors treating patients in the tents outside of the hospital where Alvarez is being treated.

Those especially at risk are people like the elderly and those with chronic diseases.

"I anticipate that as people become more mobile ... we're going to start seeing more and more patients," he said.