NQ-043 Answer: (A) Shaken-impact baby syndrome

Pathology: This is a globe with the attached optic nerve. A Bluish discoloration is noted under the optic nerve (white arrow) and in the sclera (black arrow) and are most consistent with subdural and subscleral hemorrhage. These hemorrhages are virtually hallmarks of shaken baby syndrome, also known as shaken-impact baby syndrome. It should be noted that these hemorrhages are primary hemorrhages. Extension of subdural blood from intracranial hemorrhage into the subdural space of the optic nerve from an intracranial hemorrhage should be ruled out. 

Shaken-impact baby syndrome: Shaken baby syndrome (shaken-impact baby syndrome) is usually seen before 3 years of age, most frequently occurred within the first year of life. Extracranial injury suspicious of or consistent with child abuse are seen in many but not all of the cases. A good number of cases are completely free of external injury. The nature of the injury is that of a diffuse injury of the central nervous system resulted from sudden deceleration and rotation of the brain about its center of gravity. Such angular deceleration will increase 50 times in magnitude at the time of impact of the baby on a surface. It is important to note that impact on a relatively soft surface can also cause shaken baby this type of injury. The cause of death is usually uncontrollable increase in intracranial pressure. Detection of hemorrhage in the retina and in the subdural space of optic nerves are highly suggestive of shaken baby syndrome. CT scan is a handy instrument to detect hemorrhage at the early stage. Extensive loss of gray white differentiation and hypodensity are addition features on CT scan that suggest shaken baby syndrome. MRI is very useful as it sees the edema and other features very well in contrast to CT. Pathologically, the findings in the brain are similar to those seen in acceleration-deceleration injury in motor vehicle accidents. Macroscopically, there are gliding (parasagittal) contusions. Histologically, salient feature is diffuse axonal injury characterized by neuroaxonal spheroids. Superficial contusions in the olfactory bulbs and gyrus recturs are also common. Bruising of the scalp, cranial fracture, several subdural hemorrhage can also be seen but uncommon. It is very important to note that the severity of injury to the central nervous system in shaken baby syndrome is often not well reflected by external injury to the scalp and cranial bone. Hemorrhage along the sheath of the optic nerve is typically most obvious at the junction of the neurve and the globe. A point of warning is that subarachnoid hemorrhage in the brain can extend along the subarachnoid space and mimic nerve sheath hemorrhage. Therefore, a large subarachnoid hemorrhage should be ruled out. Retinal hemorrhage is also a common feature. Cervical injury from C1 to C4 is also common. Dissection of the neck and vertebral accompanied by in situ examination of the cervical cord and brain with a posterior approach (i.e., from the back) is a good way to demonstrate injury in these regions.

Although these features are suggestive of a shaken-impact syndrome, they are not entirely sufficient alone to recognize a shaken-impact baby syndrome without doubt. Such recognition is often a clinical, pathologic, and radiologic correlation that may involve further investigation by law enforcement. One of the article that discuss these aspects are here:

Optic nerve glioma characteristically leads to expansion of the optic nerve. Subdural hemorrhage along the optic nerve is not a characteristic feature. 

Methanol intoxication is associated with spongiotic changes of the optic nerve which is a microscopic feature. Subdural and subscleral hemorrhage is not a typical feature.

Osteogenesis imperfecta: A blue hue is often seen in the sclera which is due to increased transparency of the sclera due to the presence of the pigmented choroid in the globe. The choroid layer would not extend to the sheath of the optic nerve. This rule out this answer.

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