AAP Voices Blog

The chance to save a life. It sounds a bit dramatic, but when a pediatric provider recognizes that a small and seemingly insignificant injury in an infant can be a sign of physical abuse, the provider truly can save that infant’s life.

I understood what a sentinel injury is before the term was coined. I am a child abuse pediatrician, so my phone rings after someone else, most often a frontline provider in the primary care office or emergency department, suspects possible abuse. By the time my phone rings, the diagnosis often is clear. And sadly, sometimes, when I look back at the medical records of an abused baby, I see that the baby was found to have a superficial injury not understood at the time to be what it was: a sign of physical abuse.

“Sentinel injuries are medically mild, superficial injuries that occur in young and developmentally immature infants who cannot have hurt themselves.”

I remember a 6-month-old I evaluated many years ago, so long ago that I recall reading the handwritten note in a paper chart from the evaluating provider that documented a “small linear bruise” on the infant’s calf when he was seen for a viral illness at 2 months of age. Four months later, the baby had multiple fractures and patterned bruising that was clearly inflicted.

Years later, Dr. Lynn Sheets coined the term “sentinel injury” to describe what that little bruise on the calf was. Sentinel injuries are medically mild, superficial injuries that occur in young and developmentally immature infants who cannot have hurt themselves. They include bruises, oral injuries, and subconjunctival hemorrhages. These injuries do not require medical intervention. Who treats a small bruise or a small lingual frenulum tear that is likely healing rapidly already?

But these injuries constitute a potential emergency. They are frequently a sign of abusive behavior that, if not addressed, can escalate and lead to more serious injury or even death.

Sentinel injuries pose a potent challenge and an even more potent opportunity. If recognized for what they are, life-saving intervention can follow. But even recognizing these injuries can be hard. Caregivers who have become frustrated and handled an infant so roughly that they have left a bruise on a baby’s chest wall do not usually seek help for managing their emotions. Rather, caregivers present the infant with a chief complaint of fussiness or vomiting, each leading to a long list of possible diagnoses. It may not be top of one’s mind even to look for small and subtle injuries as one starts to tick off items in a differential diagnosis list. Making it even harder, abuse can be painful to consider, especially in the setting of the longstanding and trusting relationship between pediatric provider and caregiver.

Keeping in mind the critical link between developmental ability and the power to injure oneself can help. Before infants can pull to stand and move about, they rarely hurt themselves, leading to a useful mnemonic: “Those who don’t cruise rarely bruise.” Be careful when caregivers offer nonsensical explanations for superficial findings. I have been told that a car seat caused bruises on a 2-month-old baby’s chest, and that playing with a toy caused subconjunctival hemorrhages in a 3-month-old. Once I ruled out a possible bleeding diathesis and did a full workup for possible occult injuries, I found that both babies had multiple, definitive signs of physical abuse.

If you identify a sentinel injury, urgent evaluation is warranted. Consider consultation with a child abuse pediatrician like me who can help to plan next steps, as well as a report to child protective services. Don’t wait to rule out another possible explanation for a potential sentinel injury, like a bleeding disorder, to consider abuse. More injury can occur if you delay.

April is Child Abuse Prevention Month. As a child abuse pediatrician who routinely evaluates seriously injured, physically abused infants, I see this month as an opportunity to spread the word about sentinel injuries. If every pediatric provider can recognize that even a minor injury in a small and nonmobile infant can be a possible sign of abuse, more severe injury and death can be prevented.

I hope this knowledge will underscore what I know to be true: if you recognize a sentinel injury for what it is, you can save a child’s life.

*The views expressed in this article are those of the author, and not necessarily those of the American Academy of Pediatrics.