No Set Rules Govern Imaging of Head Injuries.
About 5% of children with head injuries and normal neurologic exams turn out to have intracranial pathology But these children typically have associated symptoms suggestive of brain injury, Dr. Martha S. Wright said at a meeting on practical pediatrics sponsored by the American Academy of Pediatrics.
In older children, Dr. Wright watches for signs of more significant injury above and beyond simple concussions--such as prolonged loss of consciousness (more than 5 minutes), retrograde or anterograde amnesia, and an increase in lethargy or headache--to assess whether to order CT scans. She tends to scan patients who are vomiting if they don't improve within 1 hour.
She regularly obtains imaging for infants with head trauma who are asymptomatic but have significant scalp hematomas. She bases this practice on a study that showed intracranial injuries in 14 of 608 (2%) clinically asymptomatic infants under 2 years of age who had a large scalp swelling (Pediatrics 104[4, pt. 1]:861-67, 1999).
There are no hard and fast rules, said Dr. Wright of the division of pediatric emergency medicine at Rainbow Babies and Children's Hospital, Cleveland. Independent predictors for the presence of brain injury are still being determined.
In most patients, a detailed history and physical are all that are needed to rule out brain injury. But in many ways, CT scans provide reassurance and make the diagnosis of intracranial injury. She reviewed the main types of cranial insults that can be visualized with CT scans:
* Linear skull fractures. The "plain vanilla" of the fracture world, these have little to no clinical significance in children over age 2. Nonetheless, always consider the possibility of brain injury. Typically, fractures signify that a substantial amount of force was involved in the impact.
* Diastatic fractures. Children under 2 years old with leptomeningeal cysts from a linear fracture develop these "growing" fractures, which typically occur within 6 months of the injury and widen with time. As the dura becomes pinched and fluid accumulates, parents will tend to notice a "growth" on the side of the child's head.
* Depressed skull fractures. Although these are true neurosurgical emergencies, these children may look fine initially. A substantial scalp contusion may mask a fracture underneath that requires surgery to lift the skull fragment. This is the rare case where Dr. Wright uses skull x-rays. For huge contusions that prevent palpation of the skull, she uses cheaper plain films to determine whether a CT scan is necessary in the otherwise asymptomatic patient.
* Basilar fractures. These may look initially like simple concussions and may not be visible on CT scans, but there may be cranial nerve findings and ophthalmoplegia. There is often hematotympanum on the sides of the fracture. The classic signs of ecchymosis--raccoon eyes and Battle's sign--develop early, within hours of injury.
* Epidural hematomas. These injuries can develop from low-velocity or even seemingly inconsequential circumstances--for example, a fall off a high chair. Only about half involve skull fractures. The injuries can develop slowly if a venous rather than an arterial bleed is involved, up to 72 hours after injury instead of within the standard 48-hour window. Surgery is often required to evacuate the buildup of blood between the skull and the dura mater.
* Subdural hematomas. Occurring under the dura mater and above the cortex, subdural hematomas often result from high-velocity mechanisms such as car accidents or shaken baby syndrome. Despite the significant risk of mortality, the lesions can produce vague, nonspecific findings such as vomiting or crabbiness. Neurosurgical consultants should assess whether to evacuate the fluid.
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|Comment:||No Set Rules Govern Imaging of Head Injuries.|
|Author:||WANG, JENNIFER M.|
|Publication:||Family Practice News|
|Article Type:||Brief Article|
|Date:||Apr 15, 2001|
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