San Jose, Costa Rica ? A pre-dawn fire swept the top floors of a hospital in Costa Rica’s capital Tuesday, killing at least 18 people as it engulfed the central staircase of a building without adequate fire exits or a sprinkler system.

Medical personnel smashed their way through windows as they tried to help patients escape, while some of the sick fled on their own. People could be seen on live television climbing onto ledges of the five-story building or tying bed sheets to window frames to lower themselves to safety.

One of the victims was identified as nurse Patricia Fallas, 42, who was helping patients evacuate the fifth floor when she died of smoke inhalation. She was holding a lit flashlight when her body was found, Fire Chief Hector Chavez said.

The fire – the second this year at the 62-year-old Calderon Guardia Hospital – raised questions about safety precautions in other medical facilities throughout the Central American country.

The 2:20 a.m. blaze broke out on the fifth floor and quickly spread, consuming the top three stories until it was brought under control three hours later, the fire chief said. He said least 14 people died on the fifth floor.

Costa Rican firefighters help evacuate patients from a fire Tuesday at the Calderon Guardia Hospital in San Jose, the country's capital.

The fire affected the neurosurgery and men’s surgery departments. Some of the hospital’s 522 patients hid under their beds.

Officials feared the death toll would rise as the search for victims continued, Costa Rican Red Cross official Alexander Poras said. Survivors were taken to other hospitals.

The cause was not immediately known. Costa Rican news media reported that a gas leak was believed to be the source, but Chavez would not confirm that, telling The Associated Press the investigation was ongoing.

Like most other medical facilities in Costa Rica, the Calderon Guardia Hospital lacked an adequate evacuation plan.

The hospital alarm system failed to sound, and two small staircases designed for evacuations reached only to the third floor. Fire fighters and Red Cross rescue workers used hydraulic ladders to evacuate people.

Calderon Guardia is one of Costa Rica’s main hospitals, receiving patients from all over the country.