Shaken baby syndrome (SBS) is a form of brain trauma that occurs when an infant is intentionally and violently shaken. Injury can occur in just five seconds of shaking.

A baby has a very large head (in proportion to his/her body) and weak neck muscles. When an infant is shaken, the head quickly bobs back and forth. The forces cause the soft brain tissue to hit the harder skull, causing bruising and swelling of brain tissue and bleeding (intracerebral hemorrhage). Some of the nerve tissue in the brain may tear. Swelling and bleeding puts more pressure on the brain, leading to further damage. In addition, tiny blood vessels in the retina of the eye can hemorrhage. Sometimes a child will have arm bruises (from tight grasping), rib fractures or limb fractures.

According to the Shaken Baby Task Force, about 50,000 cases of SBS occur every year. About 25 percent of children die and up to 60 percent are left with some type of permanent disability. Brain damage caused by the trauma can lead to vision problems (including blindness), learning disabilities, seizures, hearing loss, paralysis, cerebral palsy and problems with behavior, speech or eating.

Most victims of SBS are under two. The National Shaken Baby Coalition says the average age at the time of the abuse is 4 to 6 months. In half of all cases, the offender is a parent (37 percent are biological fathers and 12 percent are mothers). The majority (81 percent) have no history of child abuse. In many cases, the incident occurs when an adult loses his/her temper over a crying or fussing baby and shakes the child out of anger.

Detecting Shaken Baby Syndrome

Signs of SBS can vary from tiredness, extreme irritability and vomiting to seizures, breathing difficulty and loss of consciousness. When a child is brought to the emergency room, doctors are most concerned with saving the victim's life. In many cases, there are no obvious signs of injury and parents may not be forthcoming in admitting to shaking the infant (or may not be aware the incident occurred at the hands of another caretaker).

Currently, the hallmark clue to SBS is retinal hemorrhage. Stephanie Zimmerman, M.D., an Emergency Medicine Specialist at Phoenix Children's Hospital, says that although retinal hemorrhage can occur along with other types of trauma (such as a fall or head injury), SBS produces very classic patterns of hemorrhage.

Phoenix Children's Hospital has recently acquired a new type of camera that emergency department workers can use to take pictures of the back of the eye. It's called a digital fundus camera. Although other cameras have been developed for this purpose, the newer hand-held camera enables a person to quickly snap a clear picture, with little training, and gain clues about what happened to the child. Zimmerman says the pictures from the camera are also helpful for prosecutors who can use the retinal images to show a jury the extent of a child's injury and potentially gain a conviction for child abuse.

Stephanie Zimmerman, M.D. (featured in story), Emergency Medicine, Phoenix Children's Hospital, 1919 E. Thomas Road, Phoenix, AZ 85016. (Media Contact: Jessica Wheeler, (602) 546-0824.)

For general information on shaken baby syndrome:

American Association of Neurological Surgeons

The Brain Injury Association

National Center on Shaken Baby Syndrome

National Institute of Neurological Disorders and Stroke

National Shaken Baby Coalition

Shaken Baby Task Force