A 17-year-old boy presents to the emergency department after a car accident. He drove his car into a pole while speeding at night. He has no past medical history and takes no medications. The patient is unable to offer a history and repetitively asks the nurses what happened. He knows his name and address and is able to remember other information about himself. He is complaining of a headache. His temperature is 97.6°F (36.4°C), blood pressure is 122/74 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 98% of room air. Physical exam reveals a confused young man. Cranial nerves 2-12 are intact and the patient has normal strength and sensation. He demonstrates a stable gait. Throughout the exam, he continuously asks what happened to him. A head CT scan is ordered. Which of the following is the most likely diagnosis?
Diffuse axonal injury
Epidural hematoma
Concussion
Subarachnoid hemorrhage
Concussion
This patient is presenting after a motor vehicle accident with confusion, repeated questioning, and a normal neurologic exam aside from his inability to remember the events that occurred. This constellation of symptoms is concerning for a concussion.

A concussion occurs after blunt trauma to the head and is common in athletics and motor vehicle collisions. Patients may present initially with symptoms including confusion, repeat questioning, repeating themselves, and amnesia surrounding the event. A thorough neurological exam is important as there should be no neurologic deficits in a concussion. Patients with a classic history and reassuring exam require rest from physical and cognitive activity. Post-concussive syndrome may present with chronic headaches, dizziness, trouble sleeping, trouble focusing, nausea, and difficulties with learning and concentrating. Mood changes such as depression and anxiety are common. Any patient with a concerning mechanism or symptoms should have a head CT to rule out other more severe diagnoses.

Pertab et al. review concussion and its presentation. They note that concussion can cause many symptoms including trouble focusing, mood changes, headaches, and also autonomic nervous system anomalies. They recommend reviewing the constellation of symptoms to make the diagnosis.

Incorrect Answers:
Answer A: Cerebral contusions are common after head trauma and may present with confusion, obtundation, neurologic deficits, and amnesia. While a severe concussion and a cerebral contusion have overlap, given this patient’s age, mechanism, and symptoms, concussion is more likely. A head CT would demonstrate contusion (hyperdense intraparenchymal lesion) with a possible contrecoup injury.

Answer C: Diffuse axonal injury occurs after a severe CNS injury with an obtunded patient who is typically unresponsive. CT imaging will show blurring of the gray-white interface with punctate hemorrhages. These patients have a very poor prognosis. They often are obtunded with minimal neurologic function.

Answer D: Epidural hematoma presents with trauma and the classic “talk and die” syndrome including a lucid interval followed by progressive obtundation and fixed, dilated pupils. Symptoms are rapidly progressive as this is an arterial bleed. CT scan would demonstrate a hyperdense lens-shaped lesion (composed of blood). A burr hole may relieve pressure and can be life-saving.

Answer E: Subarachnoid hemorrhage may present after trauma with a severe headache and meningeal signs. Patients may demonstrate focal neurologic deficits in severe cases. CT scan will demonstrate blood in the subarachnoid space and lumbar puncture would demonstrate blood in the CSF. A CTA may also localize the site of bleeding and if any aneurysm is present.

Bullet Summary:
A severe concussion can present with confusion, repeat questioning, and amnesia.