Physical Abuse: Cutaneous, Skeletal, and Abusive Head Trauma
Mechanism and development
Physical abuse is diagnosed when the injury pattern, the stated mechanism, and the child's developmental stage cannot be reconciled. The history may be absent, vague, changing, or may blame a minor fall for severe injury. A short fall from standing height rarely causes subdural hemorrhage, retinal hemorrhage, or death.
Abusive head trauma
Consider AHT when an infant presents with encephalopathy, seizures, apnea, or unexplained subdural hemorrhage. Retinal hemorrhage, especially multilayered and extending to the periphery, supports the diagnosis; absence does not exclude it. Birth-related subdural and retinal bleeding resolve over weeks; CPR rarely causes rib fractures. Avoid the term 'triad' as if it were diagnostic - findings are probabilistic.
Skeletal and cutaneous injury
High-specificity fractures include classic metaphyseal lesions, posterior rib fractures, and scapular, sternal, and spinous process fractures. Femur fracture in a nonambulatory infant is concerning. Bruising is the most common sentinel injury: use TEN-4-FACESp (Torso, Ear, Neck bruising in <4 years; any bruise in <4.99 months; Frenulum, Angle of jaw, Cheeks, Eyelids, Subconjunctival hemorrhage in <4.99 years). Patterned burns, loop marks, and bite marks are characteristic.
Evaluation and traps
Obtain a skeletal survey in children under 2 years (repeat in 2 weeks), head imaging, dilated fundoscopy, and screening labs. Traps: over-attributing findings to osteogenesis imperfecta or rickets without testing; missing a sentinel bruise in a precruising infant; accepting 'she bruises easily' without evaluation; and assuming a normal exam excludes abuse.
Rule of thumb
Any bruise in an infant who is not yet cruising is abuse until a credible alternative is established.