The 2-month-old girl in the hospital emergency room suffered severe seiziures, drifted in and ot of a coma, and was having trouble breathing.

The physicians noticed a slight bulge in her "soft spot," the top portion of the skull that remains soft in early infancy. A spinal tap revealed blood in the baby's spinal fluid and there was evidence of bleeding inside her eyes.

All the medical evidence pointed to severe head injury. But there were no bruises, fractures or other signs that the baby had been slapped or beaten. Questioned by physicians, the baby's mother said her daughter passed out after choking on a piece of food.

Ten months later, the child was permanently blind, paralyzed and mentally retarded.

This account, though not an actual case, is the kind of damage that can occur in infants and young children who are victims of "shaken baby syndrome," doctors say. It is an increasingly recognized form of child abuse that can cause permanent disability, even death. Children who survive rough shaking may suffer blindness, paralysis, mental retardation and learning disabilities.

First described in medical literature in the 1940s, shaken baby syndrome describes brain damage in infants and young children who have been roughly shaken by an adult, usually out of anger or frustration at prolonged crying. It has been called a "secret" form of child abuse because there are usually no outward signs of injury. In many cases, parents who shake their children are unaware of how deadly it can be.

It's hard to judge how common shaken baby syndrome is because many infants escape with minor injuries that go unnoticed. Even in severe cases parents and physicians may fail to make a connection between the child's symptoms and the shaking. But physicians agree that the recognized cases of shaken baby syndrome are just the tip of the iceberg. More cases are likely to be reported as physicians begin to recognize the subtle signs of the syndrome.

Dr. David L. Chadwick, a member of the American Academy of Pediatrics' Task Force on Child Abuse, said: "Shaking is almost always done in a moment of anger or rage. But most people don't think the baby's going to die or be permanently brain damaged by it."

Last January, he saw two 2-month-old boys die on the same day, apparently of injuries suffered as a result of a hard shaking. Both were brought to the emergency room unconscious and with signs of severe brain damage. They died despite vigorous intensive medical care, said Chadwick, who is the director of the Center for Child Protection at Children's Hospital and Health Center in San Diego. Between five and 10 cases of shaken baby syndrome are treated there each year, and about one third of those children die from their injuries, Chadwick said.

Severe damage from shaking is most common in infants under 6 months of age; brain damage has occurred in children over 2, but is rare. Young infants are particularly susceptible because their weak neck muscles are unable to control the motion of their relatively large, heavy heads. A shaken infant's head wobbles rapidly back and forth. The brain strikes against the inside of the skull, causing swelling and bleeding both within and on the surface of the brain.

The severe symptoms of head injury associated with shaking include seizures, coma and difficulty breathing. More subtle signs include irritability, loss of appetite, listlessness and a whiplash-like injury of the neck. Close examination of the eyes can be the key to making the diagnosis because bleeding in and around the retina is very common in children who have been shaken.

Dr. J.M. Whitworth, executive medical director of the Children's Crisis Center in Jacksonville, Fla., a regional referral center for victims of child abuse, sees 10 to 20 cases of shaken baby syndrome each year, usually in infants from 1 to 6 months of age.

"We're finding shaken baby syndrome in milder forms now because we're tending to look for retinal bleeding. When you see retinal bleeding in an infant with seizures, you put two and two together and you've got a diagnosis of shaken baby syndrome," Whitworth said.

Physicians at Children's Hospital in Philadelphia reviewed the medical records of 1,250 cases of child abuse reported from 1977 to 1982 and identified 20 previously unrecognized cases of shaken baby syndrome. The average age of the infants was 5.8 months, and the age range was 1 to 15 months. Three of the infants died; 10 suffered permanent injury, including partial vision loss or blindness, paralysis and seizures. Only seven survived with no apparent damage, said Dr. Stephen Ludwig, one of the researchers who conducted the study, and these children may turn out to have learning disabilities when they get older.

Dr. Frederick Green, who established the child abuse unit at Children's Hospital National Medical Center and is currently vice president of the National Committee to Prevent Child Abuse, said many school-age children with learning problems may have been victims of shaken baby syndrome as infants. In one typical case, a mother brought her 18-month-old son in for treatment because he was complaining of a stiff, painful neck.

"In the course of taking the child's medical history, I asked the mother about the forms of discipline she and her husband used on the child, and she admitted that her husband tended to grab the child by his shoulders and shake him hard," Green said. "Then I examined the child's eyes and saw the retinal hemorrhages." Neck X-rays revealed that the child had a neck injury similar to that seen in an adult who suffers whiplash in an automobile accident.

At Montefiore Hospital and Medical Center in New York, four infants ranging in age from 4 weeks to 4 months were admitted between 1978 and 1981 with puzzling brain and eye abnormalities. Close examination led physicians to conclude that the infants had been injured by rough shaking. All four suffered permanent injury, including severe paralysis, mental retardation and blindness.

"I probably saw particularly severe cases," said Dr. Yitchak Frank, one of the pediatric neurologists who examined the infants. "I'm sure that we miss a respectable number of cases either because the injuries are milder or because the cause of the injuries is never determined.

"But I do think that this particular form of child abuse is very dangerous and is likely to cause brain damage and blindness in a good percentage of cases." The physicians agree that one of the best ways to prevent the damage that can be caused by shaking is to alert parents to its tragic consequences. Unfortunately, they say, many parents use shaking as a disciplinary measure because they don't realize the harm it can cause. If the shaking is mild, the children may simply be a little irritable, or listless, or complain of a stiff neck for a day or two. But if the shaking continues, catastrophe can result.

"It seems to be very common for parents to respond to an infant who won't stop crying by shaking him," Ludwig said. "Luckily, most parents stop before they do any permanent damage."

The physicians' advice for parents: When you feel anger or frustration building up, ask a friendly neighbor or a family member to take over the care of the child while you relax. If such support is not available, simply leave your child crying in his crib until you regain your composure.

"If you fear you will injure your child," Green said, "it's better to move away until you can get yourself calmed down."