Initial Evaluation and Management of Suspected Non-Accidental Trauma in a 4-Month-Old
A 4-month-old infant with suspected non-accidental trauma requires an immediate skeletal survey and non-contrast head CT, regardless of whether neurologic symptoms are present, because significant intracranial injury can occur without clinical signs in infants under 12 months of age. 1
Immediate Imaging Protocol
Mandatory Initial Studies
Skeletal Survey: This is the cornerstone of evaluation for all children ≤24 months with suspected abuse 1. At 4 months, this infant falls well within the age range where skeletal survey is non-negotiable.
Non-Contrast Head CT: Even without obvious neurologic symptoms, head imaging is critical. Studies show that 29% of abused children without clinical suspicion of intracranial injury had positive neuroimaging findings (subdural hematoma, epidural hematoma, or cerebral edema), with most being under 12 months of age 1. Another study found 27% of infants <6 months with apparently isolated bruises had new injury on neuroimaging 1. Clinicians should have a low threshold for head CT in infants under 1 year, as significant traumatic intracranial pathology may occur without skull fractures, signs of head injury, or even retinal hemorrhages 1.
Conditional Imaging Based on Clinical Findings
If any signs of thoracoabdominal injury are present (abdominal bruising, distension, tenderness, vomiting, abnormal liver transaminases, or elevated pancreatic enzymes):
- Contrast-enhanced CT chest/abdomen/pelvis: Non-contrast CT is inadequate for detecting visceral injuries 1. Up to 10% of abused children have intra-abdominal injury, and nearly half require surgical intervention 1. Importantly, child abuse is associated with a 6-fold increase in odds of death compared to accidental trauma 1.
Important caveat: Routine CT screening of chest/abdomen without clinical indicators is NOT recommended 1.
Additional Neuroimaging Considerations
MRI Head
If the initial head CT is abnormal or clinical suspicion remains high, MRI provides additional diagnostic information in approximately 25% of cases 1. MRI is superior for detecting small-volume extra-axial hemorrhage and assessing prognosis 1.
MRI Cervical Spine
This should be strongly considered at the time of brain MRI, as unsuspected spinal injuries (usually ligamentous) are demonstrated in >36% of abused infants with intracranial injury 1. Cervical spine injury at the craniocervical junction is highly associated with bilateral hypoxic-ischemic injury.
Follow-Up Imaging
Repeat skeletal survey at 2 weeks post-initial evaluation is essential 1. This follow-up detects fractures missed on initial survey in 9-12% of infants, with up to one-third of follow-up surveys yielding new information 1. Half to three-fourths of newly detected fractures are rib fractures, followed by classic metaphyseal lesions 1.
Alternative if 2-Week Wait is Not Feasible
Tc-99m bone scan can be considered when immediate follow-up is needed, though it has limitations (less sensitive for skull fractures and metaphyseal injuries near growth plates, higher radiation exposure) 1.
Critical Clinical Pearls
High-Risk Indicators in a 4-Month-Old
- Any bruising in a non-mobile infant is concerning 2. At 4 months, most infants are not yet mobile, making bruising highly suspicious.
- Rib fractures (especially posterior), metaphyseal fractures, and multiple fractures at different stages of healing are classic for abuse
- Subdural hematoma is the most common intracranial finding in abusive head trauma 1
Common Pitfalls to Avoid
- Do not skip head imaging because the infant appears neurologically normal—this is the most dangerous error, as 37% of children <2 years with high-risk criteria but no overt head injury signs had occult head injury on imaging 1
- Do not use ultrasound for acute abdominal trauma evaluation—it is less sensitive than CT for detecting hemoperitoneum and solid organ injuries 1
- Do not forget the 2-week follow-up skeletal survey—initial surveys have only a 90% true negative rate 1
- Do not perform non-contrast CT for suspected visceral injuries—contrast enhancement is essential 1
Documentation and Reporting
While not explicitly detailed in the imaging guidelines provided, any suspicion of NAT requires immediate involvement of child protective services and a multidisciplinary child abuse team, which should be available 24/7 at pediatric centers 3.