Ophthalmologists positioned to prevent misdiagnosis of shaken baby syndrome

A quarter of all head injuries may be attributed to “non-accidental head injuries” in children. A proper work-up is essential and may prevent other problems.

PHILADELPHIA — Ophthalmologists are in a unique position to recognize shaken baby syndrome and help other treating physicians identify it as part of a traumatic injury.

“Recognition of the condition could potentially save a life. Ophthalmologists need to be aware of the classic findings of the differential diagnosis of retinal hemorrhage in infants. The patient’s history and examination can help support the diagnosis of shaken baby syndrome (SBS),” said Monte D. Mills, MD, director of ophthalmology at Children’s Hospital of Philadelphia.

Dr. Mills believes that SBS is significantly underdiagnosed.

“Pediatricians and others who evaluate children for head injuries and nonspecific symptoms may not recognize the possibility that trauma is involved. Correct diagnosis cannot only improve the patient’s treatment, but may prevent other major problems including recurrent episodes of SBS,” he said.

For example, neonates in the first 1 or 2 weeks of life may have retinal hemorrhages.

“But these are usually gone by week 4 or 5. We know that retinal hemorrhages are actually very rare with other types of trauma, such as car accidents and falls,” he said.

Context and semantics

Dr. Mills believes that it is important that non-accidental head injuries and non-accidental retinal hemorrhages be considered in the context of child abuse.

“The epidemiology is enormous. One quarter of all hospital admissions for head injury are non-accidental head injury in these young kids,” he said.

This entity involving children younger than 2 years old with retinal hemorrhages and intracranial hemorrhages was originally termed battered child or whiplash shaken infant.

“The terminology and semantics have evolved through the years. Today the preferred terminology, at least at our institution, is non-accidental head injury,” he said.

Defining criteria are bleeding in the head and bleeding in the eye. Pre-retinal hemorrhages can also develop into vitreous hemorrhages. In addition, an autopsy may find scleral hemorrhages, optic nerve hemorrhages and orbital hemorrhages.

“As ophthalmologists, we know that the hemorrhages occur at all levels of the retina and throughout the entire retina, from optic nerve to ora serrata. There are also very peculiar and almost pathognomonic circular retinal folds that really only occur among young children,” Dr. Mills said.

Excluding other possibilities

“These are kids with severe closed head injuries,” Dr. Mills said. “There are few or no signs of direct head or eye injury, although this is slightly semantic because some people use the terminology ‘shaken impact syndrome’ to describe children who obviously have signs of impact as well, while excluding all other medical causes of the bleeding.” To call it a non-accidental injury, “you have to exclude the possibility of leukemia or another severe hematologic abnormality that might have caused the bleeding.”

Dr. Mills believes the threshold for retinal hemorrhage is probably higher than the threshold for intracranial hemorrhage.

“There are children who have been shaken or have been injured, who don’t have retinal hemorrhages, [but] it is very uncommon to have children with retinal hemorrhages who don’t have intracranial hemorrhages. The threshold for the eye injuries seems to be higher than the threshold for the brain injuries,” he said.

Specifically, the eye findings are characterized by hemorrhages of all layers of the retina and the vitreous and pre-retinal space. Bleeding in the optic nerve, subretinal space and sclera is also often present.

“Circular retinal folds seem to be related to vitreous attachments to the area of the retinal arcade blood vessels. Papilledema, although not necessarily characteristic, can occur as well,” he said.

Late signs, which are less well understood, include optic atrophy, retinal changes, vitreous opacities, cortical blindness or central visual impairment, amblyopia and myopia.

“We need to study what happens to these kids and what their chance is of developing some of these late signs as opposed to full recovery,” he said.

Controversial diagnoses

Many controversies in the diagnosis of SBS hinge on how certain a practitioner is in describing retinal hemorrhages in the context of non-accidental injury vs. “Could it have happened some other way?” For instance, there may be a child who has received CPR after the initial illness but before an eye exam.

“Particularly when an associated coagulation disorder occurs in the extremeness of resuscitation and CPR, could that have caused the retinal hemorrhages after the initial onset of the illness but before the eye exam occurred?” Dr. Mills asked.

Two syndromes that cause great confusion, especially among non-ophthalmologists, are Terson’s syndrome, which is rare in infants, and Purtscher retinopathy.

“Terson’s syndrome was described originally as an acute, ruptured, intracranial arterial aneurysm where there is intracranial hemorrhage and intraocular hemorrhage,” Dr. Mills said. “I think clinically it can be discriminated from the appearance of the fundus. In Terson’s syndrome, the hemorrhages appear to emanate from the optic disc and in the posterior pole.”

Purtscher retinopathy is also used in a confusing way to describe babies with SBS.

“It is actually a distinct syndrome in which chest compression causes retinal hemorrhages,” Dr. Mills said.

Terson’s syndrome is classically associated with adults, in which there is an arterial bleed in the brain (usually a ruptured aneurysm) that results in hemorrhage in the eye, including the retina and the vitreous.

Dr. Mills believes that in most cases the ocular findings are sufficient to make these various differentials very low.

“Even without a history of abdominal or chest compression or intracranial aneurysms, these ocular findings are enough to exclude the possibility of most of these differentials,” he said.

In suspected cases of child abuse, “your lowest concern is being offensive by raising the issue, while your greatest concern is protecting the child and making sure this doesn’t happen again,” he said. “There are situations where children have gone home and died because nobody did the proper work-up.”

For Your Information:

• Monte D. Mills, MD, can be reached at division of ophthalmology, Wood Center First Floor, 34th St. and Civic Center Blvd., Philadelphia, PA 19104; (215) 590-2791.