Epidural hematoma: when a “minor” head injury may prove to be fatal
Nitin K Sethi, MD
Assistant Professor of Neurology
New York-Presbyterian Hospital
Weill Cornell Medical Center
New York, NY 10065
Many of you must have read about the tragic demise of actress Natasha Richardson from blunt (closed) head trauma she sustained after falling on a ski slope. While exact details about the extent and nature of her injuries are unclear, it drew attention to blunt (closed) head trauma. I shall discuss about the same here.
Broadly speaking head injuries can be of two types: penetrating head injuries and closed head injuries. An example of a penetrating head injury is a gun shot wound to the head or when a person is involved in a motor vehicle accident with significant polytrauma (including fracture of the skull and bleeding into the brain). Penetrating head injuries are usually easily identified by first responders (emergency medical services such as the ambulance crew responding first to the call). Usually there is an obvious scalp laceration and blood is seen oozing from the site of the injury. Later when the patient is transferred to the hospital, the extent of the injury can be better documented. For this usually a CT scan of the brain is done (at times a MRI brain may be carried out). Penetrating head injuries vary depending upon the mechanism of injury (example velocity, trajectory and size of the bullet in the case of gun shot wounds to the head). Patients with penetrating head trauma are critical and require urgent stabilization usually in an intensive care setting.
It is the closed head injuries though which can be a little deceiving and that is where I shall like to steer this discussion. The mechanism of closed head injuries is usually blunt trauma to the head (example a fall, a blow to the head while boxing and so on). One special type of closed head injury is a concussive injury from an improvised explosive device (IED). These IED related injuries have become the signature injury in the battlefields of Iraq and Afghanistan. But moving away from the battlefield, closed head injuries are frequent. Most of them are mild as the ones sustained while playing contact sports like football or boxing or when you get up in the middle of the night to go get a glass of water only to bump your head against a door. One “sees stars” for a while but is none the worse for wear apart from a bruised head and maybe ego (especially if you are like me and love to box). But can seemingly innocuous looking closed head injuries prove to be fatal? Can a “minor” fall or blow to the head kill you?
Well yes and this brings us to epidural hematomas. Let us assume you suffer a “minor” closed head injury. What you may ask exactly is “minor” closed head injury. Well it usually refers to an injury in which there is no prolonged loss of consciousness (example is a concussion after a blow to the head or a fall). As the scalp is not lacerated there is no obvious external bleeding. The patient may suffer a minor black out (loss of consciousness for a few seconds to minutes) but soon is awake and seems alert and able to answer questions.
Imagine a boxer, who walks into a straight right. BOOM!!! Down he goes. The referee counts him out. It is a KO. The ring side doctor rushes in. The boxer eyes are glazed but he is coming around and slowly is able to get up and walk out of the ring unassisted. Nothing but a bruised ego and a black eye. He shall live to fight another day you may say as a spectator but the next day you read in the papers that the boxer was found dead in his bed. What happened here? Well the answer is simple. Even though the boxer seemed to have a suffered a “minor” closed head injury, a far more sinister injury process started silently in the brain. The blow to the head caused one of the small arteries (usually a branch of the middle meningeal artery) to start leaking blood. This blood starts collecting in the potential space between the brain and the skull (we call this the epidural space and hence a collection of blood in this space is called an epidural hematoma). As the leak is small, the patient seemingly recovers and looks fine. He may answer questions appropriately and hence may decide not to seek further medical attention. This interval where the patient (in our case our boxer) looks fine and seems to have recovered from the head blow is called the LUCID INTERVAL (the patient is lucid, makes sense and looks normal). But things are already starting to go wrong. The small leak from the ruptured blood vessel leads to progressive accumulation of blood in the epidural space. When the epidural hematoma becomes large, it has no place to expand (remember there is a rigid bony skull which prevents the blood from coming out). So the underlying brain starts getting squashed. This leads to a depression in the level of consciousness as the pressure inside the brain increases. If the elevated intracranial pressure is not brought down urgently the patient may die (we call this herniation of brain due to elevated intracranial pressure).
Could our boxer have been saved? Yes by all means. If he had been kept under observation (sometimes we like to observe patients with closed head trauma overnight in the hospital), then the first signs of raised intracranial pressure would have been picked up. Usually this is a change in the level of consciousness (the boxer would have become drowsy or hard to wake up, may have complained of headache). An urgent CT scan would have revealed the epidural collection of blood and neurosurgical evacuation of the blood would have been carried out (the skull is opened and the blood is drained out. The bleeding vessel is identified and cauterized to achieve homeostasis).
So what are the take home points from our boxer’s story?
-some “minor” looking closed head injuries can indeed prove to be fatal.
-patients should be observed after a closed head injury. If the decision is made not to go to the hospital, have a friend or family member check on the patient at multiple points.
-the earliest change in the patient’s level of consciousness warrants a stat transfer to the nearest hospital and further investigations.