Abusive Head Trauma (AHT)
Formerly: Shaken Baby Syndrome / Infantile Whiplash Syndrome
1. Pathophysiology
AHT involves violent shaking of an infant, often with or without impact. The infant’s anatomy—large head-to-body ratio, weak neck musculature, and unmyelinated brain tissue—makes them uniquely susceptible to rapid acceleration-deceleration forces.
2. The Classic “Triad.”
While not present in every case, the presence of these three findings is highly suggestive of AHT:
- Subdural Hemorrhage (SDH): Resulting from the tearing of bridging veins due to rotational forces.
- Retinal Hemorrhages (RH): Often bilateral, extensive, and layered; highly specific for AHT when severe.
- Encephalopathy: Manifesting as an altered level of consciousness, seizures, or respiratory distress due to cerebral edema.
3. Differential Diagnosis & Forensic Pearls
| Diagnostic Consideration | Clinical Note |
|---|---|
| Accidental Trauma | Short-distance falls (e.g., from a couch) rarely cause the severe triad; history must be scrutinized. |
| Metabolic/Genetic | Rule out Glutaric Aciduria Type I or Menkes disease, which can mimic SDH. |
| Skeletal Survey | Mandatory to look for “healing” fractures (ribs, metaphyses), providing evidence of previous abuse. |
4. Investigative Keys
- History vs. Findings: A common forensic red flag is a “story” that does not match the severity of the neurological injury (e.g., “the baby just stopped breathing” without mention of trauma).
- Documentation: Meticulous recording of physical injuries, including the specific locations and ages of bruises (e.g., pinna of the ear, torso).
- Multidisciplinary Input: Requires coordination between ophthalmology, radiology, neurology, and forensic pathology to establish the mechanism of injury.