Inflicted head trauma constitutes the leading cause of nonaccidental death associated with child abuse (8, 9). When caregivers provide a history that is inadequate to explain the extent of head injury, child abuse must be considered. In a population-based study, Keenan et al. documented an incidence of traumatic brain injury among children younger than 2 as 17 per 100,000 (95% CI, 13–21 per 100,000 year); the incidence was seven times greater for children younger than 1 year of life (10). Perpetrators of nonaccidental head trauma are usually male (in decreasing frequency: father, stepfather, and mother’s boyfriend). Mothers and female baby-sitters have also been implicated (11, 12). Risk factors for AHT are similar to those for child abuse in general. The child may be premature or have a difficult temperament or chronic illness (6). The family may have the stressors of poverty, drug abuse, parental depression, low education level, or other males (stepfathers and boyfriends) living in the home (13).

Shaken baby syndrome (SBS) is classically described as occurring in infants younger than 6 months, with minimal or no external signs of trauma, subdural hematomas, and retinal hemorrhages (6). It usually presents as a spectrum of findings, including intracranial, cervical cord, intraocular, skeletal, and cutaneous injuries. Caretakers may be unaware of the specific injuries that can be caused by shaking, but it is reported that the act of shaking or slamming can be so violent that competent individuals observing the shaking would recognize it as dangerous (14). SBS has also been called shaken impact syndrome, based on the combination of autopsy findings in infants who were fatally abused and of biomechanical studies not performed on humans. The study concluded that severe head injuries require impact, not shaking alone (15). However, most authors claim that impact is not needed. Most also agree that inflicted head trauma encompasses a constellation of findings, with or without impact (6), thereby producing the general terms of nonaccidental head trauma, inflicted head trauma, or AHT.

It is important to distinguish between accidental and inflicted head injuries. Most short vertical falls in infants, usually less than 4 feet (most childhood falls), result in minor injury or no injury at all. Although falls from low heights may cause linear, unilateral skull fractures without intracranial injury, significant force is required to sustain depressed, stellate, complex, bilateral, or basilar skull fractures. Other than the rare reported cases of epidural hemorrhage, falls from low heights do not cause significant intracranial pathology, including subdural or subarachnoid hemorrhage, or retinal hemorrhage (15, 16, 17, 18). Child abuse must be considered in children with intracranial injuries but without a history of motor vehicle trauma, falls from heights greater than 4 feet, or head impact from a moving object.

In AHT there may be an absence of external findings to implicate nonaccidental trauma (19). The degree of injury depends on the force or severity of the shake or impact and the time elapsed from the event. Symptoms may be vague and occur intermittently, which may be misleading to evaluating physicians (20). The range of manifestations includes poor feeding, vomiting, lethargy, irritability, colic, apnea, seizures, and death (6). Children in one study were seen and diagnosed by physicians with other conditions 2.8 times before being diagnosed with inflicted head injury (7).

Intracranial pathology encountered in AHT includes, most commonly, subdural hemorrhages along with parenchymal injuries, including diffuse axonal injury (DAI). During shaking, because the infant’s head is heavy and the neck muscles are weak, intracranial bleeding results from a tearing of cortical bridging veins, which stretch and shear as the head is subjected to rotational forces. These same inertial forces and rotational acceleration forces also permit tearing of axons in the child’s incompletely myelinated brain, resulting in DAI, contusions, parenchymal tears, and cerebral edema (21). Other intracranial pathology includes subarachnoid hemorrhage and cerebral contusions. Contusions and lacerations are proportional to the contact forces applied. Skull fractures are seen in these cases but can also be seen with unintentional trauma. In general,
because there may be similarities in the types of skull fractures in unintentional and intentional injury, abuse should be suspected if the injury does not correlate with the history and the physical examination findings. Multiple bilateral skull fractures should be reviewed carefully as to a possible abusive source but may be explained by some types of unintentional injury (22). Parenchymal injury is also seen secondary to hypoxia and ischemia (23). The incidence of epidural hematoma is low (6, 7, 8). On the basis of a study of head-injured children younger than 3 years of age, Wells et al. (24) reported that 78% of epidural hemorrhages were felt to be unintentional compared with 18% associated with abuse.

Shaken infants are also at risk for cervical cord injury because of the infant’s large head-to-torso ratio and weak neck musculature. Spinal cord contusions and subdural and epidural hematomas at the cervicomedullary junction may lead to morbidity and mortality (6).

Retinal hemorrhages are associated with extraordinary force and are rare occurrences in minor unintentional trauma (25, 26, 27). Unilateral or bilateral retinal hemorrhages are present in 75% to 95% of cases of AHT (20). Retinal hemorrhages do occur with unintentional trauma, birth trauma, bleeding disorders, and glutaric aciduria type I, for example, but diffuse and severe retinal hemorrhages are considered specific for AHT. In AHT, retinal hemorrhages usually involve the multiple layers of the retina and extend outside the posterior pole to the periphery and oro serrata, to the periphery of the retina (28). Retinal folds or detachment may also develop (5). In children with birth trauma, retinal hemorrhages may be seen (in approximately 30% of newborns), but they resolve by the age of 4 weeks (6). Retinal hemorrhage after cardiopulmonary resuscitation (CPR) has been reported (rarely), but not in the absence of previous head trauma or abnormal coagulation and platelet studies. When such hemorrhage is found, it tends to be morphologically different from that associated with AHT (29, 30).

The interval between head injury and symptom onset may help identify a perpetrator. Determining whether a lucid interval has occurred can be difficult because perpetrators may not be telling the truth (31). Gilliland found that neurologic changes and severe symptoms, such as difficult breathing, unresponsiveness, and respiratory collapse, occurred less than 24 hours after head injury in most of the incidents. Of note, whenever information was supplied by someone other than the perpetrator, the child was not described as normal during the period (32). Starling et al., studying perpetrators, found that 97% of convicted perpetrators who admitted to inflicting head trauma were with the child at the time of onset of symptoms, suggesting that symptoms occur soon after the abuse, as opposed to emerging over hours or days (11). In a more recent study of perpetrator admissions, perpetrators said symptoms appeared immediately after the abuse (33). In a retrospective review of 95 unintentional fatalities involving head injury, only one patient, with an epidural hematoma, had a lucid interval (34).

Another controversy is the theory of rebleeding, after minor or no trauma, into chronic or subacute subdural hemorrhages. This theory has implications in identifying a perpetrator. After reviewing the literature in 1999, Block concluded that “there is no evidence to support the current concept that rebleeding of an organizing subdural hemorrhage can occur from a subsequent trivial injury and cause severe neurologic impairment or death” (29). However, there have been rare reports that led investigators to continue to examine the issue. In 2002, Hymel et al. published two case reports involving indoor, unintentional, and pediatric closed head trauma that resulted in intracranial rebleeding. Both impacts occurred in medical settings and were witnessed by medical personnel (35).

Physicians should be aware that intentional head trauma is often associated with extracranial signs of abuse, although physical findings such as cutaneous bruising may or may not be present (12). Posterior rib fractures can occur because of squeezing the infant’s chest while shaking the infant (36). Long-bone fractures may be present. In one review, 32% of the victims had long-bone fractures because of repetitive abuse (36). The physician should perform a careful search for other physical signs of abuse or neglect.

Both solid and hollow organs are at risk for injury in thoracoabdominal trauma. Abdominal trauma is the second most common cause of child abuse deaths (37, 38). Although motor vehicle crashes (MVCs) are the leading cause of major abdominal trauma in children, child abuse poses a greater risk of subsequent death. In fact, compared with unintentional injuries, including MVC, the mechanism of child abuse increases the likelihood of death from traumatic abdominal injuries sixfold (39). Unfortunately, children who sustain severe abdominal trauma from child abuse often present late for medical attention (39). Generally, their presentation is in response to the pathology that results from abdominal injury rather than to the injury itself (40). Blunt abdominal trauma can result in no external evidence of injury, even if there is severe organ and tissue damage (39, 40, 41). Initial manifestations may be nonspecific and include abdominal pain and distention, nausea, vomiting, and fever. Peritonitis and associated sepsis may become evident within
hours to days after abdominal injury, whereas hematoma and subsequent intestinal obstruction usually take longer, possibly days, to diagnose. Multiple injuries are seen in 18% to 37% of children with inflicted abdominal trauma (37).

Sometimes older children can describe the causative event. In the case of a younger child, diagnosis of abdominal trauma may rest on the history provided by the caretaker or on the suspicion of the physician. As with head trauma, the absence of any history, or the report of a minor injury despite evidence of serious trauma, should raise suspicion that the injury may have been inflicted.

Nonaccidental blunt thoracic trauma can result in rib fractures and injury to underlying structures. Lower rib fractures may lacerate the spleen or liver. Rib fractures can cause pneumothorax or pneumomediastinum. Direct blunt anterior trauma can lead to esophageal perforation, pneumomediastinum, or mediastinitis.

The spleen and the liver can sustain damage when the lower ribs are fractured. Blunt abdominal trauma may cause contusions of these organs as well. Liver injury can range from small, asymptomatic contusions to fractures that lead to significant blood loss and death. Delay in evaluation of severe liver injury increases pediatric mortality. Diagnosis of liver injury may be determined by a history of blunt abdominal trauma, abdominal pain and tenderness, elevated aspartate aminotransferase/alanine aminotransferase, and computed tomography findings. Elevated liver enzymes can be helpful in evaluating occult liver injuries, even when there is no report of abdominal trauma or clinical evidence of abdominal injury (38). The spleen can be injured in both unintentional and intentional trauma scenarios, but inflicted injury should be suspected when the patient is an infant who is not yet able to walk.

In general, pancreatic injury is not common in childhood (38), but when present it may be the result of inflicted trauma. In addition to MVCs, incidents involving impact against seat belts or bicycle handlebars may damage this potentially volatile organ. Injury to the pancreas requires deep abdominal wall indentation (37). In a recent review of pancreatic trauma in children, as with abdominal trauma in general, MVC was the leading cause of pancreatic injury. Child abuse was the third most common cause of injury and the second most common cause of death in children with pancreatic injuries (42).

Injury to either or both kidneys can result from blunt thoracoabdominal trauma. The kidneys are generally well protected by the lower ribs but are not completely protected from blunt or penetrating trauma.

The abdominal viscera are also at risk of injury from blunt trauma associated with child abuse. In general, the small intestine is protected from blunt abdominal trauma, but the fixed retroperitoneal course of the duodenum renders it vulnerable (43). The duodenum is the abdominal structure most frequently injured in MVCs. The second most frequent mechanism is child abuse (44). Most children with duodenal injuries have associated trauma, including bruises, acute and healing rib fractures, and long-bone fractures. The most common form of duodenal injury from blunt trauma is intramural hematoma, resulting in partial obstruction, nausea, and vomiting. In some cases, the duodenum is ruptured and/or transected. Because delay in seeking treatment is common after abdominal trauma resulting from child abuse, peritonitis may be significant when the child is brought to the emergency department.

The ileum and jejunum are less prone to injury from blunt trauma. Ileal and jejunal injuries manifest as hematoma or perforation (37).

The colon and rectum can be injured by blunt mechanisms, usually resulting in bruising or perforation. In addition, pelvic trauma may lead to rectal injury, as can anal penetration. Substantial blunt force is required to injure these organs. Absence of plausible history and delay in seeking treatment are indicators of abuse.