# Non-Accidental Trauma in Children

## Overview

Non-accidental trauma, also termed abusive head trauma, refers to intentional injury inflicted on a child, most often by a caregiver. AHT is the leading cause of death from child abuse and the leading cause of traumatic death in infants. Peak incidence occurs in children under two years of age, especially those younger than six months. Mortality reaches 20 to 30 percent in severe cases, and survivors frequently suffer significant neurological morbidity. The neurosurgeon plays a critical role in recognizing injury patterns, meticulously documenting findings, and understanding medico-legal reporting obligations.

## Terminology

The historical term "shaken baby syndrome" is now considered imprecise. Abusive head trauma is the preferred consensus term adopted by the American Academy of Pediatrics in 2009. This terminology encompasses shaking, impact, shaking-impact, and other mechanisms while avoiding mechanistic assumptions.

## Mechanisms of Injury

### Shaking

Rapid acceleration-deceleration forces applied to the infant's head cause injury through several pathways. The infant's large head-to-body ratio, weak neck muscles, and unmyelinated brain amplify the forces transmitted. Bridging veins are torn by differential motion between the brain and skull, producing subdural hematoma. Retinal hemorrhages result from vitreous traction.

### Impact

Direct blows to the head may leave scalp bruising or skull fractures. Impact can occur in combination with shaking, termed shaking-impact syndrome. Contact injuries produce focal findings including epidural hematoma, skull fracture, and scalp swelling.

### Combined Mechanism

The most common pattern in fatal cases shows evidence of both acceleration-deceleration injury, with subdural hematoma and retinal hemorrhages, and impact injury, with skull fracture and scalp contusion.

## Clinical Presentation

### Classic Triad of AHT

The classic triad consists of subdural hematoma, especially bilateral, interhemispheric, or posterior fossa; retinal hemorrhages, especially multilayered and extending to the periphery; and encephalopathy manifesting as altered consciousness, seizures, or apnea.

### Red Flags Suggesting Abuse

Key warning signs include a history inconsistent with the injury pattern or developmental stage of the child, changing or vague explanations from caregivers, delay in seeking medical attention, multiple injuries of different ages, injuries in non-mobile infants (summarized by the principle "those who don't cruise, rarely bruise"), injury attributed to a minor mechanism that is disproportionate to the severity observed, and previous emergency department visits for reportedly accidental injuries.

### Presentation Patterns

Acute severe presentations include an unresponsive, seizing, or apneic infant with a bulging fontanelle. Subacute presentations feature irritability, poor feeding, vomiting, and lethargy. Chronic presentations show enlarging head circumference, developmental regression, and chronic subdural collections.

## Injury Patterns

### Subdural Hematoma

Subdural hematoma is the most characteristic intracranial finding in AHT. It is typically thin and bilateral, located over the convexities and in the interhemispheric fissure. Mixed-density collections with both acute and chronic components suggest repeated injury. Posterior fossa subdural hematoma is uncommon in accidental trauma, and its presence raises significant concern for abuse. Bilateral subdural hematoma in infants should be considered AHT until proven otherwise. The mechanism is tearing of bridging veins from angular acceleration-deceleration forces.

### Subarachnoid Hemorrhage

Subarachnoid hemorrhage commonly accompanies subdural hematoma in AHT. It is typically thin and diffuse but is less specific than subdural hematoma for abuse.

### Parenchymal Injury

Diffuse axonal injury results from shearing of axons by rotational forces. Contusions are more common with impact mechanisms. Hypoxic-ischemic injury from apnea, seizures, or increased ICP may be the primary cause of devastating outcomes. CT demonstrates bilateral hemispheric edema and loss of gray-white matter differentiation. The reversal sign, where white matter appears denser than edematous gray matter on CT, indicates severe global ischemia and carries a very poor prognosis.

### Retinal Hemorrhages

Retinal hemorrhages are present in 60 to 85 percent of AHT cases. They are most specific for abuse when multilayered, involving preretinal, intraretinal, and subretinal layers, extensive extending to the periphery, bilateral, and numerous. They are less specific when few in number, flame-shaped, limited to the posterior pole, as these can be seen in accidental trauma, coagulopathy, and birth trauma in neonates under six weeks. Traumatic retinoschisis, the splitting of retinal layers, is highly specific for AHT. All children with suspected AHT must receive dilated indirect ophthalmoscopy by an ophthalmologist. Birth-related retinal hemorrhages resolve by six weeks; hemorrhages identified after six weeks of age cannot be attributed to birth.

### Skeletal Injuries

Classic metaphyseal lesions, manifesting as bucket-handle or corner fractures of long bone metaphyses, are highly specific for abuse and result from shearing forces applied by twisting or pulling limbs. Posterior rib fractures in infants from squeezing are highly specific for abuse. Multiple fractures of different ages represent a pathognomonic pattern. Skull fractures that are complex, bilateral, cross suture lines, or are depressed raise concern, though simple linear parietal fractures can occur with accidental falls. A skeletal survey is mandatory in all children under two years with suspected abuse, and a repeat survey at two weeks is recommended to detect healing fractures that become visible as callus forms.

### Spinal Injuries

Cervical spine injuries including ligamentous damage, subdural hematoma, and cord injury can result from violent shaking. These are often overlooked, and MRI of the spine should be considered in severe AHT.

## Diagnostic Workup

### Imaging

Non-contrast CT of the head is the first-line study for acute presentations, identifying subdural and subarachnoid hemorrhage, edema, and fractures. MRI is more sensitive than CT for diffuse axonal injury, parenchymal injury, posterior fossa subdural hematoma, and dating of hemorrhage. Susceptibility-weighted imaging detects microhemorrhages, MR spectroscopy may help assess prognosis, and MRI should be obtained in all suspected AHT cases when feasible. A skeletal survey with AP and lateral views of all long bones, hands, feet, ribs, pelvis, spine, and skull is mandatory, with a follow-up survey at two weeks recommended. Spine MRI is obtained if neurological deficits suggest spinal involvement.

### Laboratory

Complete blood count and coagulation studies including PT, PTT, INR, and fibrinogen rule out coagulopathy. Liver function tests and lipase screen for occult abdominal trauma, which is present in 10 to 20 percent. Urinalysis assesses for renal injury. Metabolic workup with amino acids and organic acids is obtained if a metabolic condition is suspected.

### Ophthalmologic Examination

Dilated indirect ophthalmoscopy by an ophthalmologist is mandatory. Documentation should include the number, type, distribution, and laterality of hemorrhages. Retinal photography with a RetCam system provides medicolegal documentation.

## Differential Diagnosis

Accidental trauma presents with a history consistent with the mechanism and appropriate for the child's developmental stage. Birth trauma may produce subdural hematoma in neonates under six weeks and retinal hemorrhages that resolve by six weeks, but should not explain injury in older infants. Coagulopathy from factor deficiencies or vitamin K deficiency bleeding should be excluded with coagulation studies. Glutaric aciduria type I can produce macrocephaly, subdural hematoma, and retinal hemorrhages; urine organic acids are diagnostic. Osteogenesis imperfecta explains multiple fractures but does not produce subdural hematoma or retinal hemorrhages. Benign external hydrocephalus features enlarged subarachnoid spaces with or without subdural hematoma in developmentally normal, well-appearing children. Arteriovenous malformation is a rare cause of hemorrhage in infants. These differentials should be considered but must not delay child protection measures.

## Neurosurgical Management

### Acute Management

Initial stabilization follows pediatric trauma protocols with attention to airway, breathing, and circulation. Intubation is required for GCS less than 8 or respiratory compromise. Seizures are treated aggressively with lorazepam, levetiracetam, or phenobarbital. ICP management includes head elevation, osmotherapy, and EVD placement if needed. Surgical evacuation of significant subdural or epidural hematoma is performed for mass effect or neurological deterioration, though many thin bilateral subdural hematomas do not require evacuation. Subdural taps through the fontanelle may provide acute decompression in infants. Decompressive craniectomy for refractory ICP elevation is controversial in AHT because outcomes are often poor given the severity of underlying brain injury.

### Chronic Subdural Collections

Chronic collections may require serial subdural taps, subdural-peritoneal shunting, or craniotomy. Recurrence is common, and re-accumulation does not necessarily indicate reinjury.

## Prognosis

Mortality reaches 20 to 30 percent in severe AHT. Among survivors, 60 to 70 percent have significant long-term neurological disability including motor deficits with cerebral palsy, cognitive impairment, seizure disorders, cortical visual impairment, and behavioral problems. Prognostic indicators include GCS at presentation, bilateral hemispheric edema, the reversal sign on CT, and absent cortical activity on EEG.

## Medico-Legal Responsibilities

All healthcare providers are mandatory reporters for suspected child abuse in all jurisdictions. A report to child protective services should be made immediately upon suspicion; definitive proof is not required. Documentation must be meticulous and objective, recording who provided the history, any inconsistencies, direct quotes, physical examination findings with photographs when possible, imaging findings, and the timeline of events. A multidisciplinary child abuse team including social work, child abuse pediatrics, ophthalmology, and radiology should be engaged. The patient must not be discharged to the suspected abuser, and child protection holds should be secured. Neurosurgeons may be called to provide expert testimony and must deliver factual, evidence-based testimony. The neurosurgeon should not serve as the sole diagnostician of abuse but should collaborate with child abuse pediatricians.

<image>Non-contrast axial CT scan of the brain in a 4-month-old infant with abusive head trauma, demonstrating bilateral thin acute subdural hematomas over the cerebral convexities with a hyperdense acute interhemispheric subdural collection, diffuse cerebral edema with loss of gray-white matter differentiation, and effacement of the basal cisterns</image>

<image>Fundoscopic photograph (RetCam image) of the retina of an infant with abusive head trauma, showing extensive multilayered retinal hemorrhages (preretinal, intraretinal, and subretinal) extending from the posterior pole to the far periphery bilaterally, with a dome-shaped preretinal hemorrhage overlying the macula</image>

<image>Anteroposterior radiograph of the lower extremities of an infant as part of a skeletal survey, demonstrating classic metaphyseal lesions (bucket-handle fractures) at the distal femoral and proximal tibial metaphyses bilaterally, consistent with non-accidental injury from twisting or pulling forces on the extremities</image>

## Clinical Pearls

The triad of subdural hematoma, retinal hemorrhages, and encephalopathy in an infant without an adequate accidental explanation is highly concerning for abusive head trauma until proven otherwise. The principle that "those who don't cruise, rarely bruise" means that bruising in a pre-mobile infant under six months is abnormal and should trigger investigation. Retinal hemorrhages extending to the periphery and involving multiple layers are highly specific for AHT, while isolated posterior pole hemorrhages are less specific. Never discharge a child to a suspected abuser; child protective services involvement is mandatory and urgent. A normal skeletal survey does not rule out abuse; the follow-up survey at two weeks is essential because healing fractures become visible as callus forms. Document findings objectively, avoiding conclusory language such as "this is child abuse" in the chart; instead describe findings as "consistent with" or "concerning for" abusive head trauma. The neurosurgeon's primary role is to treat the child's injuries and recognize concerning patterns; definitive determination of abuse is made by the multidisciplinary team and legal system.

## References
1. Christian CW, Block R; Committee on Child Abuse and Neglect. Abusive head trauma in infants and children. Pediatrics. 2009;123(5):1409-1411.
2. Duhaime AC et al. Nonaccidental head injury in infants: the "shaken-baby syndrome." N Engl J Med. 1998;338(25):1822-1829.
3. Kemp AM et al. Neuroimaging: what neuroradiological features distinguish abusive from non-abusive head trauma? A systematic review. Arch Dis Child. 2011;96(12):1103-1112.
4. Maguire SA et al. Retinal haemorrhages and related findings in abusive and non-abusive head trauma: a systematic review. Eye. 2013;27(1):28-36.
5. Choudhary AK et al. Consensus statement on abusive head trauma in infants and young children. Pediatr Radiol. 2018;48(8):1048-1065.