Paediatric head injury: when to image and when to observe

PECARN application (children ≥2 years):

Predictors of clinically important traumatic brain injury (ciTBI):

1. GCS <15 or other signs of altered mental status - absent (GCS 15, behaving normally).
2. Palpable skull fracture - absent.
3. History of loss of consciousness - absent.
4. Vomiting - absent.
5. Severe mechanism - fall >1.5 m in a child ≥2 years is a criterion; this fall is approximately 1.5 m, which is at the threshold. The mechanism is borderline rather than clearly severe.
6. Severe headache - not reported (child is playful).

Risk category: The child has no PECARN predictors of ciTBI (or at most a borderline mechanism), placing him in the very low risk group (ciTBI risk <0.05%).

Recommendation:

1. CT is not indicated on PECARN grounds. The risk of ciTBI is very low, and the radiation risk from a paediatric head CT (particularly in a 3-year-old) is not negligible (lifetime attributable risk of fatal cancer of the order of 1 in 1,000–10,000 per scan, higher in younger children).
2. Observation for 4–6 hours in the emergency department or a short-stay unit is appropriate, with parental education and written head injury advice.
3. Return precautions: advise the mother to return if the child becomes drowsy, vomits repeatedly, has a seizure, has unequal pupils, or has any focal weakness.
4. Document the PECARN assessment and the discussion with the mother, including the rationale for not scanning.
5. Reassure the mother that the decision is based on a validated clinical rule and that observation is the safer option for her child.

Approach:

1. Acknowledge her anxiety and validate her concern; explain that you understand why she wants reassurance.
2. Explain the reasoning in plain language: the PECARN rule is a validated tool used worldwide; her son has none of the features that predict a serious brain injury; a CT would expose him to radiation that carries a small but real long-term cancer risk, and the scan is unlikely to change management.
3. Offer alternatives: observation in the department with regular neurological checks, written head injury advice, and a clear plan for return. Offer to review him again before discharge.
4. Involve a senior clinician (paediatric emergency consultant or on-call paediatrician) to discuss with the mother if she remains insistent; a second opinion can be helpful and is good practice.
5. Shared decision-making: if, after full discussion, the mother still wishes a CT, consider whether there are any clinical features that would justify scanning (e.g. a change in behaviour, vomiting, or a palpable fracture that was not initially appreciated). If none, it is reasonable to decline the scan while documenting the discussion and offering observation. Coercing a scan against clinical judgement is not appropriate, but nor is dismissing her concerns.
6. Document the discussion, the PECARN assessment, the advice given, and the mother's response.

Medico-legal considerations:

1. Best interests of the child are paramount; the decision should be based on clinical evidence, not parental demand.
2. Record the counselling in detail, including the risks and benefits discussed and the alternatives offered.
3. Escalate if there is conflict; involve a senior clinician and, if necessary, the trust's mediation or patient advice service.
4. Do not document in a way that is disparaging of the mother; remain professional and objective.
5. Follow local safeguarding policy if there are any concerns about the mechanism of injury or the history (e.g. inconsistency, delay in presentation, previous injuries); in this case the history is consistent and there are no safeguarding concerns, but this should be considered.

Approach in an infant <2 years:

1. PECARN criteria differ for children <2 years: predictors include GCS <15 or altered mental status, palpable skull fracture, non-frontal scalp haematoma, loss of consciousness ≥5 seconds, severe mechanism, and not acting normally per parent.
2. Non-frontal scalp haematoma is a predictor in this age group; a parietal haematoma would therefore be a positive predictor, placing the infant at intermediate risk (ciTBI risk ~0.9%).
3. Recommendation: For intermediate-risk infants, PECARN recommends observation versus CT. Observation for 4–6 hours with serial neurological checks is acceptable if the child is otherwise well and the parents are reliable; CT is recommended if there is any deterioration or if observation is not feasible.
4. Lower threshold for imaging in infants because: (i) clinical assessment is harder; (ii) signs of raised intracranial pressure may be subtle; (iii) non-accidental injury must be considered, particularly with a non-frontal haematoma or inconsistent history.
5. Safeguarding: in an 8-month-old, a fall from a slide is unusual; the history should be carefully documented, and if there is any inconsistency, a safeguarding referral should be considered. A skeletal survey and ophthalmological examination may be indicated if non-accidental injury is suspected.
6. Radiation risk is higher in infants, so the decision must balance the increased clinical risk against the higher radiation sensitivity. Observation is often preferred if the child is well.
7. Communication with parents should be clear, empathetic, and documented, explaining the rationale for observation or CT.
8. Follow-up: ensure the infant is reviewed by a paediatrician before discharge and that the parents have clear return instructions.