by Stacey Chamberlain
A 20-month-old female was going up some wooden stairs, slipped, fell down four stairs, and hit the back of her head on the wooden landing at the bottom of the stairs. She did not lose consciousness and cried immediately. She was consolable after a couple of minutes and is acting normal per her parents. She has not vomited. On exam, she is well-appearing, alert, and has a normal neurologic exam. She is noted to have a left parietal hematoma measuring approximately 4×4 cm.
Should you get CT imaging of this child to rule out clinically significant head injury?
PECARN Pediatric Head Trauma Algorithm
Age < 2
Age ≥ 2
- GCS < 15, palpable skull fracture, or signs of altered mental status
- Occipital, parietal or temporal scalp hematoma; History of LOC≥5 sec; Not acting normally per parent or Severe Mechanism of Injury?
- GCS < 15, palpable skull fracture, or signs of altered mental status
- History of LOC or history of vomiting or Severe headache or Severe Mechanism of Injury?
The PECARN (Pediatric Emergency Care Applied Research Network) Pediatric Head Trauma Algorithm was developed as a CDR to minimize unnecessary radiation exposure to young children. The estimated risk of lethal malignancy from a single head CT in a 1-year-old is 1 in 1000-1500 and decreases to 1 in 5000 in a 10-year-old. Due to these risks, in addition to costs, length of stay and potential risks of procedural sedation, this CDR is widely employed given the frequency of pediatric head trauma ED visits. This CDR has the practitioner use a prediction tree to determine risk, but unlike some other risk stratification tools, the PECARN group does make recommendations based on what they consider acceptable levels of risk. In the less than 2-year-old group, the rule was found to be 100% sensitive with sensitivities ranging from 96.8%-100% sensitive in the greater than two-year-old group.
This algorithm does have some complexity and ambiguity. It requires the practitioner to know what were considered signs of altered mental status and what were considered severe mechanisms of injury. In addition, certain paths of the decision tree lead to intermediate risk zones. In these cases, the recommendation is “observation versus CT,” allowing for the ED physician to base his/her decision to image or not based on numerous contributory factors including physician experience, multiple versus isolated findings, and parental preference, among others.
Other pediatric head trauma CDRs rules have been derived and validated; however, in comparison trials, PECARN performed better than the other CDRs. Of note, in this study, physician practice (without the use of a specific CDR) performed as well as PECARN with only slightly lower specificity.
Case Discussion
For purposes of the case study, the patient falls into an intermediate risk zone of clinically important brain injury. However, a sub-analysis of patients less than two years old with isolated scalp hematomas suggests that patients were higher risk if they were < 3 months of age, had non-frontal scalp hematomas, large scalp hematomas (> 3cm), and severe mechanism of injury. Given the large hematoma in the case study patient and a severe mechanism of injury (a fall of > 3 feet in the under two age group), one might more strongly consider imaging due to these two additional higher risk factors.
