Let’s go and see your next patient in the pediatric ER: a 4 month baby with a chief complaint of “head injury”.
Mom says that she was playing with the baby yesterday. While playing, the baby kicked and then hit his head against the wall! He cried immediately for 10 minutes and then calmed down. He did not fall, did not pass out, did not vomit, did not seize, has been eating and drinking well with no change in behavior. Today mom noticed a swelling on his head and brought him to the ER to be checked out.
You examine the baby. He keeps smiling at you during the whole exam! He looks totally fine. Vitals are perfect. Exam is also perfect; except for… an area of swelling on the left parietal skull. When you touch it the baby does not even stop smiling! It does not look tender at all.
What do you want to do?! You are trying to convince yourself to send him home, or at least just observe. You hate CTing a 4 month old, both for the radiation exposure and for possible sedation. The event was 24 hours ago, he has had no seizure, no vomiting, no LOC, he is currently well, he was already observed for 24 hours! However you need to find a rational for your thinking. So you quickly search for criteria for imaging in minor head trauma.
You look at the PECARN head trauma rules
Let’s see, GCS is 15, there is no AMS, and there is no palpable skull fracture … what?! Skull fracture?!
You go back to the child. While singing “the wheels of the bus go round and round”, you palpate the skull. Is there a fracture? Am I palpating a step off underneath this boggy swelling? How the heck should I know?!
You want to look at other sources, trying other criteria to find something to get away from CT. You look at Tintinalli (2) which addresses a couple of studies and comes up with a nice practical consensus table 132-2. You pass the left column, patient is not high risk! Second column, let’s see … no vomiting, no LOC, no change in behavior! Now the third column, titling “Intermediate Risk for Skull Fracture”. You read: “Large, non frontal hematoma”. You are stuck in this column. The recommendation is: 6 hours observation or CT or Skull x ray to detect skull fracture! You already observed for 6 hours, right? So … Ah. This skull fracture thing is killing you!
You don’t like unnecessary radiation. Skull X ray is too old fashioned and it misses up to 25% of the fractures. Should you just observe for 6 more hours in addition to 24? You are still not sure if there is a “palpable fracture” or not! Wait a minute … is it possible that ultrasound can help you see a skull fracture?
You get excited and do a brief Google search. It might work! Studies give a sensitivity of 82-100% for ultrasound to detect skull fracture in pediatric head trauma. (3,4)
You want to give it a try. You pick up the linear probe of your ultrasound, and when the baby is in bed, put it on the skull and follow the bright white line of the skull bone to find any gap, and you find these:
Now you cannot get away from the CT, but feel much less bad about unnecessary radiation. The baby has a bottle of formula and falls asleep, you are fortunate that you do not need sedation. These are the pictures from the CT:
There is a depressed skull fracture that you previously discovered with your bedside ultrasound; and an epidural hematoma laying under it. Although you might correctly argue that no intervention is necessary, this is a very significant finding. Thankfully you did not send this child home!
A systematic review published one year ago concluded that although ultrasound is useful to detect skull fracture, based on current studies its sensitivity “is insufficient to recommend it for routine use in the management of pediatric head injury, particularly, given the incidence of intracranial injury without skull fracture”. They recommended that clinical decision rules and CT imaging remain the gold standard. However, given that skull fracture itself is a major criteria in clinical decision rules, when in doubt, using ultrasound can be very useful.
So next time that you have a head trauma, especially with hematoma, look for your ultrasound!
Just as a reminder, in children under 2 years, skull hematoma in places other than the frontal area is a major sign associated with intracranial injury. Search the head carefully for hematoma. The younger the child, the more important is this fining. Frontal hematoma however does not really matter! (2,6)
Finally, don’t forget to investigate child abuse in cases of significant child trauma!
- 1-PECARN head trauma rules, brief and practical:
- 2-Tintinalli on pediatric head trauma: 1,2
- 3-Ultrasound Evaluation of Skull Fractures in Children: A Feasibility Study
- 4-Ability of emergency ultrasonography to detect pediatric skull fractures: a prospective, observational study.
- 5-Is ultrasound scanning as sensitive as CT in detecting skull fractures in children presenting following head injury?
- 6-Minor head trauma in children; a chapter from up to date that puts everything together nicely