This injury is highly indicative of a shaken baby. Other findings such as retinal hemorrhages and a suspicious history add to the strength of this etiology. An experienced physician who has done many lumbar punctures in infants usually knows when to expect bloody CSF due to the difficulty of the procedure. If bloody CSF is unexpectedly encountered, and it does not clear, one should be highly suspicious of intracerebral hemorrhage with blood entering the subarachnoid space. Although blood should not appear in the CSF if the hemorrhage is purely subdural, this injury is not purely subdural in nature.
Blood also enters the subarachnoid space.
Axonal shearing and generalized cerebral cellular injury take place as well. A full fontanelle is not always indicative of meningitis. Intracerebral hemorrhage, cerebral edema, and acute hydrocephalus can all mimic the same clinical features. Trauma specialists have often taught that intracranial hemorrhage alone cannot account for all the blood loss in a patient in hypovolemic shock. In other words, if you have diagnosed an intracerebral hemorrhage in a trauma patient in hypovolemic shock, you must look elsewhere for additional hemorrhaging sites, such as in the abdomen.