Story highlights 4-year-old Frankie Delgado inhaled water while swimming on vacation

Dry drowning is the result of water left in the lungs that causes swelling

(CNN) A week after swimming on a family vacation, a 4-year-old boy from Texas took his last breath. The suspected cause of death is "dry drowning," a rare condition in which there is a delayed physical reaction to inhaling water.

Frankie Delgado was playing in knee-deep water during a Memorial Day weekend trip to Texas City Dike when a wave from a distant ship knocked him over and his head went under, said his father, Francisco Delgado Jr. A family friend picked him up, and Frankie said he was OK.

"He had fun the rest of the day," Delgado said. "I never thought nothing of it."

The next night, Frankie began to vomit and have diarrhea. Delgado and his wife had taken the boy to the doctor for similar symptoms before and were told it was a stomach bug, so they decided to treat him at home. Doctors now suspect these symptoms were the result of the water he had inhaled the day before.

Frankie's father said they initially thought their son's symptoms were due to a stomach bug.

The problems continued that week, and after Frankie woke one night complaining of shoulder pain, Delgado decided to take him to the doctor the next morning.

Read More