This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
Why a rule for head CT in children?
Head injuries are a very common reason for children to visit the emergency department. A CT scan finds bleeding quickly, but it exposes the developing brain to radiation, which slightly increases the lifetime risk of cancer. The PECARN rules, from the Pediatric Emergency Care Applied Research Network, were derived and validated by Kuppermann and colleagues in The Lancet in 2009 on more than 42,000 children. They identify children at very low risk who can safely avoid a scan.
Who they apply to
Children under 18 with a Glasgow Coma Scale of 14 or 15, seen within 24 hours of a head injury. There are two rules: one for children under 2 years and one for children 2 years and older.
The items
| Under 2 years | 2 years and older |
|---|---|
| GCS 14 or altered mental status | GCS 14 or altered mental status |
| Palpable skull fracture | Signs of basilar skull fracture |
| Occipital, parietal or temporal scalp hematoma | Any loss of consciousness |
| Loss of consciousness of 5 seconds or more | Vomiting |
| Not acting normally per parent | Severe headache |
| Severe mechanism of injury | Severe mechanism of injury |
Items in bold define the high-risk group: CT is recommended, with about a 4% risk of a clinically important brain injury. Any other item defines the intermediate-risk group, about 1%, in which observation or CT is chosen depending on the number of findings, worsening symptoms, age under 3 months and the parents’ preference. With no item at all, the risk is very low: under 0.02% under 2 years and under 0.05% from 2 years, and CT is not recommended.
What “clinically important” means
The study counted death, neurosurgery, intubation for more than 24 hours, or hospital admission for 2 nights or more because of a brain injury seen on CT. Small findings that needed no treatment were not counted.
Example
A 5-year-old fell off a bike with a helmet, cried right away, vomited once and is now playing normally. Vomiting is an intermediate-risk item, so a period of observation in the department is a common choice.
Limits
The rules do not apply to children with bleeding disorders, shunts, known brain tumors, or suspected abuse, or to penetrating injuries. Any child who gets worse at home, with repeated vomiting, unusual sleepiness or a worsening headache, should come back or call 911.