If doctors can't get a good explanation for a baby's internal head injury, they should assume shaken baby syndrome, the American Academy of Paediatrics (AAP) says.
Shaken baby syndrome may be under-recognised and under-diagnosed, the organisation says. Doctors should become familiar with its symptoms and ask parents how they respond to their crying baby, the AAP recommends.
Dr Randell Alexander, a professor at the Morehouse School of Medicine in Atlanta says that while there's no surge in reports of shaken baby syndrome, doctors should be aware of the problem and act to prevent it.
"Doctors are pretty good around the country at diagnosing the problem - there isn't anything that quite looks like shaken baby syndrome," Alexander says. "But a recent article pointed out that when a child has symptoms like not eating well, or is vomiting, or is lethargic and the cause is not some infectious disease, a doctor's first thoughts should be of shaken baby syndrome."
Most cases of shaken baby syndrome result from a parent's frustration at an infant's crying, and the shaking probably lasts about 20 seconds or less, with perhaps as many as 40 to 50 shakes, he says.
"The baby's head is going back and forth about two-and-a-half to three times a second. It's like you shook a pillow so hard that the stuffing is flying around the room; that's the kind of violence we are talking about. That directly damages brain cells, and if enough [cells] are damaged, the brain will swell, putting pressure on vital centres that control breathing and heartbeat," Alexander says.
"Not only are brain cells injured, blood vessels around the brain can be injured, and that's where we get the bleeding between the brain and the skull and behind the eyes," he says.
The National Centre on Shaken Baby Syndrome (NCSBS) says approximately 20 percent of cases of shaken baby syndrome are fatal in the first few days after injury. Survivors often suffer from handicaps ranging from mild learning disorders or behavioural changes to profound mental and developmental retardation, paralysis, blindness or a permanent vegetative state.
Alexander says doctors need to anticipate the problem and suspect all parents if the symptoms are suspicious.
"Doctors are like the rest of us. They have biases. They don't think of shaken baby syndrome as much with people of a higher socioeconomic class as they do with those who are poor. One of the things we wanted to do with this statement was to alert physicians to consider the abuse with everyone," Alexander says.