A 4 month old child is brought to the ER by his grandparents because he was difficult to arouse and was vomiting. The child had a upper respiratory infection last week that he picked up from the other kids at the babysitter's. Grandparents report that he did not fall recently. The child has his immunizations up to date. On exam the child is lethargic and responsive only to painful stimuli. Vitals signs are as listed. The cardiorespiratory exam is normal, the abdomen is soft and non-tender.  Skin exam shows no rash. Signs of meningeal irritation are not present. The child has normal tone and reflexes are 3+. Fundoscopic exam shows retinal hemorrhages. Labs shows CBC and differential: normal, glucose normal, lactacte normal. CXR shows healed rib fractures.